VII.

THEORISTS OF THE EIGHTEENTH CENTURY.

"I have read 'Frank,'" said Will Withers, "and 'Harry and Lucy,' and the 'Parents' Assistant,' and 'Sandford and Merton,' and 'Henry Milner.' In fact, there are few of those books, all kindred volumes, which I have not read. They have had an important effect upon my later life."

"Hinc illae lachrymae," in a low tone from Clem Waters.

For Colonel Ingham, the turn taken by the conversation had a peculiar charm. He was of the generation before the rest, and what were to them but ghostly ideals were to him glad memories of a happy past.

"Good!" said he. "'Frank' was, in a sense, the greatest book ever written. Do you remember that part where Frank lifted up the skirts of his coat when passing through the greenhouse?" he asked of Mabel.

"I should think I did," said Mabel and Will. As for Bedford, he had only a vague recollection of it. The others considered the conversation to be trembling upon the verge of insanity.

"Perhaps," said Florence, gently, "I might be allowed to suggest that although you have heard of 'Frank' and those other persons mentioned, we have not. I do not think that I ever heard of an inventor named Frank,—did he have any other name?—and I am usually considered," she went on modestly, "tolerably well informed. Therefore the present conversation, though probably edifying in a high degree to those who have read 'Frank,' or who have some interest in horticulture and greenhouses, can hardly fail to be very stupid to those of us who have not."

"My dear child," said the Colonel, "you are right. Mabel and I, and Will and Bedford here, are of the generation that is passing off the stage. We look back to the things of our youth, hardly considering that there are those to whom that period suggests Noah and his ark."

"But who is the inventor?" asked some one who thought that the conversation was gradually leaving the trodden path.

"Oh, we had almost forgotten him," said Bedford.

"The inventor," said Mabel, producing two volumes from under her arm, "is Mr. Richard Lovell Edgeworth, the father of Maria Edgeworth."

"What did he invent?" asked many of the company.

"He invented the telegraph."

"Well, I never knew that before."

"I thought Morse invented the telegraph."

"Didn't Dr. Franklin invent the telegraph?"

"I thought Edison—"

Other remarks were also made, showing a certain amount of incredulity.

"You mistake," said Bedford, placidly; "you are all of you under a misapprehension. I think that you all of you allude to the electric telegraph,—an invention of a later date than that of Mr. Edgeworth, and one of more value, as far as practical affairs are concerned. No; Mr. Edgeworth invented, or thinks he invented, the telegraph as it was used in the eighteenth century and the early part of the nineteenth, sometimes named the Semaphore. It wasn't a difficult invention, and I don't believe it ever came to any very practical use as constructed by Edgeworth, though French telegraphs were very useful."

"What kind of a telegraph was it?"

"Well, it was just the kind of a telegraph that the conductor of a railroad train is when he waves his arms to the engineer to go ahead. There's an account of it by Edgeworth in one of these books, with pictures to it."

"But my chief interest about Edgeworth," said Mabel, "is in his memoirs, which are written partly by himself and partly by his daughter. They are really very amusing. He was married five times,—once with a door-key when he was only fourteen."

This startling intelligence roused even Colonel Ingham to demand particulars. Was he married to all five at once? to all of them when he was only fourteen?

"No," admitted Mabel, with some regret; "he was married to them, all at different times, and he was divorced from the one he married at fourteen with the door-key."

"They were only married for fun," said Bedford. "It was all a joke. They were at a wedding, and they thought it would be funny after the real marriage to have a mock one. So they did, and married Edgeworth to a girl who was there. It was a real marriage, for they were afterwards divorced."

"Well," said Sam Edmeston, "I shall be glad to hear about this gentleman, I'm sure, though I never did hear of him before. But may I ask why it was necessary to introduce him by means of an allusion to 'Frank' and other works which we have few of us ever read, though it is very possible that we may some of us have heard of them?"

"I see why Mabel spoke first of 'Frank,'" said Colonel Ingham. "And I think that she did very well to bring Edgeworth in as she has done. And Edgeworth, though I had not thought of him before, is very fit to be one of our inventors, not so much for his individual accomplishments, which were little more than curious,—telegraph and all,—as for being a good representative of his age. Those of you who know a little of the century between 1750 and 1850 know that it was an age to which many of the secrets of physical science were being opened for the first time. Everybody was going back to Nature to see what he could learn from her. This movement swept all over France and England. Every gentleman dabbled in the sciences, and made his experiments and inventions. Voltaire in France had a great laboratory made for him in which he passed some years in chemical experiments. It was the age, too, of great inventions,—of the application of physical forces to the life of man. The invention of the steam-engine by Watt, and the applications of it to the locomotive and the steamboat, came along toward the end of this period, and marked the work of the greatest men. But every one could not invent a steam-engine. So, by the hundreds of country gentlemen who studied science, chemistry, and astronomy, and the rest, there were constructed hundreds of orreries, globes, carriages, model-telegraphs, and such things; and it is of these men that Edgeworth is the best, or at least the most available, representative, on account of his very interesting memoirs.

"Such books as 'Harry and Lucy' and 'Frank' are the mirror of this movement. But to this is joined something more, which John Morley speaks of in saying, 'An age touched by the spirit of hope turns naturally to the education of the young.' Then people knew that their own times were about as worthless as times could well be; but as they learned more, they began to hope that things were improving, and that the children might see better times than those in which the fathers lived. And as physical science was to them an all-important factor in this approaching millennium, they took pains to teach these things to the young. Any of you who have read 'Frank' or 'Sandford and Merton' will see what I mean. It was the hope that the children might be able to take the work where the fathers left it, and carry it on. And the children did. But I do not believe that any one of these eighteenth-century theorists had the first or vaguest idea of the point to which his children and grandchildren would carry his work.

"So much for Mr. Edgeworth from my point of view," concluded the Colonel. "You will hear what he thought of himself from Bedford."

EDGEWORTH'S TELEGRAPH.

[DESCRIBED BY HIMSELF.]

Bets of a rash or ingenious sort were in fashion in those days, and one proposal of what was difficult and uncommon led to another. A famous match was at that time pending at Newmarket between two horses that were in every respect as nearly equal as possible. Lord March, one evening at Ranelagh, expressed his regret to Sir Francis Delaval that he was not able to attend Newmarket at the next meeting. "I am obliged," said he, "to stay in London. I shall, however, be at the Turf Coffee House. I shall station fleet horses on the road to bring me the earliest intelligence of the event of the race, and shall manage my bets accordingly."

I asked at what time in the evening he expected to know who was winner. He said about nine in the evening. I asserted that I should be able to name the winning horse at four o'clock in the afternoon. Lord March heard my assertion with so much incredulity as to urge me to defend myself; and at length I offered to lay five hundred pounds, that I would in London name the winning horse at Newmarket at five o'clock in the evening of the day when the great match in question was to be run. Sir Francis, having looked at me for encouragement, offered to lay five hundred pounds on my side; Lord Eglintoun did the same; Shaftoe and somebody else took up their bets; and the next day we were to meet at the Turf Coffee House, to put our bets in writing. After we went home, I explained to Sir Francis Delaval the means that I proposed to use. I had early been acquainted with Wilkins's "Secret and Swift Messenger;" I had also read in Hooke's Works of a scheme of this sort, and I had determined to employ a telegraph nearly resembling that which I have since published. The machinery I knew could be prepared in a few days.

Sir Francis immediately perceived the feasibility of my scheme, and indeed its certainty of success. It was summer-time; and by employing a sufficient number of persons, we could place our machines so near as to be almost out of the power of the weather. When we all met at the Turf Coffee House, I offered to double my bet; so did Sir Francis. The gentlemen on the opposite side were willing to accept my offer; but before I would conclude my wager, I thought it fair to state to Lord March that I did not depend upon the fleetness or strength of horses to carry the desired intelligence, but upon other means, which I had, of being informed in London which horse had actually won at Newmarket, between the time when the race should be concluded and five o 'clock in the evening. My opponents thanked me for my candor and declined the bet. My friends blamed me extremely for giving up such an advantageous speculation. None of them, except Sir Francis, knew the means which I had intended to employ; and he kept them a profound secret, with a view to use them afterwards for his own purposes. With that energy which characterized everything in which he engaged, he immediately erected, under my directions, an apparatus between his house and part of Piccadilly,—an apparatus which was never suspected to be telegraphic. I also set up a night telegraph between a house which Sir F. Delaval occupied at Hampstead, and one to which I had access in Great Russell Street, Bloomsbury. This nocturnal telegraph answered well, but was too expensive for common use.

Upon my return home to Hare Hatch, I tried many experiments on different modes of telegraphic communication. My object was to combine secrecy with expedition. For this purpose I intended to employ windmills, which might be erected for common economical uses, and which might at the same time afford easy means of communication from place to place upon extraordinary occasions. There is a windmill at Nettlebed, which can be distinctly seen with a good glass from Assy Hill, between Maidenhead and Henly, the highest ground in England south of the Trent. With the assistance of Mr. Perrot, of Hare Hatch, I ascertained the practicability of my scheme between these places, which are nearly sixteen miles asunder.

I have had occasion to show my claim to the revival of this invention in modern times, and in particular to prove that I had practised telegraphic communication in the year 1767, long before it was ever attempted in France. To establish these truths, I obtained from Mr. Perrot, a Berkshire gentleman, who resided in the neighborhood of Hare Hatch, and who was witness to my experiments, his testimony to the facts which I have just related. I have his letter; and before its contents were published in the Memoirs of the Irish Academy for the year 1796, I showed it to Lord Charlemont, President of the Royal Irish Academy.

MR. EDGEWORTH'S TELEGRAPH IN IRELAND.

[DESCRIBED BY HIS DAUGHTER.]

In August, 1794, my father made a trial of his telegraph between Pakenham Hall and Edgeworth Town, a distance of twelve miles. He found it to succeed beyond his expectations; and in November following he made another trial of it at Collon, at Mr. Foster's, in the county of Louth. The telegraphs were on two hills, at fifteen miles' distance from each other. A communication of intelligence was made, and an answer received, in the space of five minutes. Mr. Foster—my father's friend, and the friend of everything useful to Ireland—was well convinced of the advantage and security this country would derive from a system of quick and certain communication; and, being satisfied of the sufficiency of this telegraph, advised that a memorial on the subject should be drawn up for Government. Accordingly, under his auspices, a memorial was presented, in 1795, to Lord Camden, then Lord Lieutenant. His Excellency glanced his eye over the paper, and said that he did not think such an establishment necessary, but desired to reserve the matter for further consideration. My father waited in Dublin for some time. The suspense and doubt in which courtiers are obliged to live is very different from that state of philosophical doubt which the wise recommend, and to which they are willing to submit. My father's patience was soon exhausted. The county in which he resided was then in a disturbed state; and he was eager to return to his family, who required his protection. Besides, to state things exactly as they were, his was not the sort of temper suited to attendance upon the great.

The disturbances in the County of Longford were quieted for a time by the military; but again, in the autumn of the ensuing year (September, 1796), rumors of an invasion prevailed, and spread with redoubled force through Ireland, disturbing commerce, and alarming all ranks of well-disposed subjects. My father wrote to Lord Carhampton, then Commander-in-Chief, and to Mr. Pelham (now Lord Chichester), who was then Secretary in Ireland, offering his services. The Secretary requested Mr. Edgeworth would furnish him with a memorial. Aware of the natural antipathy that public men feel at the sight of long memorials, this was made short enough to give it a chance of being read.

(Presented, Oct. 6, 1796.)

Mr. Edgeworth will undertake to convey intelligence from Dublin to Cork, and back to Dublin, by means of fourteen or fifteen different stations, at the rate of one hundred pounds per annum for each station, as long as Government shall think proper; and from Dublin to any other place, at the same rate, in proportion to the distance: provided that when Government chooses to discontinue the business, they shall pay one year's contract over and above the current expense, as some compensation for the prime cost of the apparatus, and the trouble of the first establishment.

In a letter of a single page, accompanying this memorial, it was stated, that to establish a telegraphic corps of men sufficient to convey intelligence to every part of the kingdom where it should be necessary, stations tenable against a mob and against musketry might be effected for the sum of six or seven thousand pounds. It was further observed, that of course there must be a considerable difference between a partial and a general plan of telegraphic communication; that Mr. Edgeworth was perfectly willing to pursue either, or to adopt without reserve any better plan that Government should approve. Thanks were returned, and approbation expressed.

Nothing now appeared in suspense except the mode of the establishment, whether it should be civil or military. Meantime Mr. Pelham spoke of the Duke of York's wish to have a reconnoitring telegraph, and observed that Mr. Edgeworth's would be exactly what his Royal Highness wanted. Mr. Edgeworth in a few days constructed a portable telegraph, and offered it to Mr. Pelham. He accepted it, and at his request my brother Lovell carried it to England, and presented it to the Duke from Mr. Pelham.

During the interval of my brother's absence in England, my father had no doubt that arrangements were making for a telegraphic establishment in Ireland. But the next time he went to the castle, he saw signs of a change in the Secretary's countenance, who seemed much hurried,—promised he would write,—wrote, and conveyed, in diplomatic form, a final refusal. Mr. Pelham indeed endeavored to make it as civil as he could, concluding his letter with these words:—

The utility of a telegraph may hereafter be considered greater; but I trust that at all events those talents which have been directed to this pursuit will be turned to some other object, and that the public will have the benefit of that extraordinary activity and zeal which I have witnessed on this occasion in some other institution which I am sure that the ingenuity of the author will not require much time to suggest.

I have the honor to be, with great respect, &c.,

T. Pelham.

Dublin Castle, Nov. 17, 1796.

Of his offer to establish a communication from the coast of Cork to Dublin, at his own expense, no notice was taken. "He had, as was known to Government, expended £500 of his own money; as much more would have erected a temporary establishment for a year to Cork. Thus the utility of this invention might have been tried, and the most prudent government upon earth could not have accused itself of extravagance in being partner with a private gentleman in an experiment which had, with inferior apparatus, and at four times the expense, been tried in France and England, and approved." The most favorable supposition by which we can account for the conduct of the Irish Government in this business is that a superior influence in England forbade them to proceed. "It must," said my father, "be mortifying to a viceroy who comes over to Ireland with enlarged views and benevolent intentions, to discover, when he attempts to act for himself, that he is peremptorily checked; that a circle is chalked round him, beyond which he cannot move."

No personal feelings of pique or disgust prevented my father from renewing his efforts to be of service to his country. Two months after the rejection of his telegraph, on Friday the 30th of December, 1796, the French were on the Irish coasts. Of this he received intelligence late at night. Immediately he sent a servant express to the Secretary, with a letter offering to erect telegraphs, which he had in Dublin, on any line that Government should direct, and proposing to bring his own men with him; or to join the army with his portable telegraphs, to reconnoitre. His servant was sent back with a note from the Secretary, containing compliments and the promise of a speedy answer; no further answer ever reached him. Upon this emergency he could, with the assistance of his friends, have established an immediate communication between Dublin and the coast, which should not have cost the country one shilling. My father showed no mortification at the neglect with which he was treated, but acknowledged that he felt much "concern in losing an opportunity of saving an enormous expense to the public, and of alleviating the anxiety and distress of thousands." A telegraph was most earnestly wished for at this time by the best-informed people in Ireland, as well as by those whose perceptions had suddenly quickened at the view of immediate danger. Great distress, bankruptcies, and ruin to many families, were the consequences of this attempted invasion. The troops were harassed with contrary orders and forced marches, for want of intelligence, and from that indecision which must always be the consequence of insufficient information. Many days were spent in terror and in fruitless wishes for the English fleet. One fact may mark the hurry and confusion of the time; the cannon and the ball sent to Bantry Bay were of different calibre. At last Ireland was providentially saved by the change of wind, which prevented the enemy from effecting a landing on her coast.

That the public will feel little interest in the danger of an invasion of Ireland which might have happened in the last century; that it can be of little consequence to the public to hear how or why, twenty years ago, this or that man's telegraph was not established,—I am aware; and I am sensible that few will care how cheaply it might have been obtained, or will be greatly interested in hearing of generous offers which were not accepted, and patriotic exertions which were not permitted to be of any national utility. I know that as a biographer I am expected to put private feelings out of the question; and this duty, as far as human nature will permit, I hope I have performed.

The facts are stated from my own knowledge, and from a more detailed account in his own "Letter to Lord Charlemont on the Telegraph,"—a political pamphlet, uncommon at least for its temperate and good-humored tone.

Though all his exertions to establish a telegraph in Ireland were at this time unsuccessful, yet he persevered in the belief that in future modes of telegraphic communication would be generally adopted; and instead of his hopes being depressed, they were raised and expanded by new consideration of the subject in a scientific light. In the sixth volume of the "Transactions of the Royal Irish Academy," he published an "Essay on the Art of Conveying Swift and Secret Intelligence," in which he gives a comprehensive view of the uses to which the system may be applied, and a description, with plates, of his own machinery. Accounts of his apparatus and specimens of his vocabulary have been copied into various popular publications, therefore it is sufficient here to refer to them. The peculiar advantages of his machinery consist, in the first place, in being as free from friction as possible, consequently in its being easily moved, and not easily destroyed by use; in the next place, on its being simple, consequently easy to make and to repair. The superior advantage of his vocabulary arises from its being undecipherable. This depends on his employing the numerical figures instead of the alphabet. With a power of almost infinite change, and consequently with defiance of detection, he applies the combination of numerical figures to the words of a common dictionary, or to any length of phrase in any given vocabulary. He was the first who made this application of figures to telegraphic communication.

Much has been urged by various modern claimants for the honor of the invention of the telegraph. In England the claims of Dr. Hooke and of the Marquis of Worcester to the original idea are incontestable. But the invention long lay dormant, till wakened into active service by the French. Long before the French telegraph appeared, my father had tried his first telegraphic experiments. As he mentions in his own narrative, he tried the use of windmill sails in 1767 in Berkshire; and also a nocturnal telegraph with lamps and illuminated letters, between London and Hampstead. He refers for the confirmation of the facts to a letter of Mr. Perrot's, a Berkshire gentleman who was with him at the time. The original of this letter is now in my possession. It was shown in 1795 to the President of the Royal Irish Academy. The following is a copy of it:—

Dear Sir,—I perfectly recollect having several conversations with you in 1767 on the subject of a speedy and secret conveyance of intelligence. I recollect your going up the hills to see how far and how distinctly the arms (and the position of them) of Nettlebed Windmill sails were to be discovered with ease.

As to the experiments from Highgate to London by means of lamps, I was not present at the time, but I remember your mentioning the circumstance to me in the same year. All these particulars were brought very strongly to my memory when the French, some years ago, conveyed intelligence by signals; and I then thought and declared that the merit of the invention undoubtedly belonged to you. I am very glad that I have it in my power to send you this confirmation, because I imagine there is no other person now living who can bear witness to your observations in Berkshire.

I remain, dear Sir,

Your affectionate friend,

James L. Perrot.

Bath, Dec. 9, 1795.

Claims of priority of invention are always listened to with doubt, or, at best, with impatience. To those who bring the invention to perfection, who actually adapt it to use, mankind are justly most grateful, and to these, rather than to the original inventors, grant the honors of a triumph. Sensible of this, the matter is urged no farther, but left to the justice of posterity.

I am happy to state, however, one plain fact, which stands independent of all controversy, that my father's was the first, and I believe the only, telegraph which ever spoke across the Channel from Ireland to Scotland. He was, as he says in his essay on this subject, "ambitious of being the first person who should connect the islands more closely by facilitating their mutual intercourse;" and on the 24th of August, 1794, my brothers had the satisfaction of sending by my father's telegraph four messages across the Channel, and of receiving immediate answers, before a vast concourse of spectators.

Edgeworth to Dr. Darwin.

Edgeworthtown, Dec. 11, 1794.    

I have been employed for two months in experiments upon a telegraph of my own invention. I tried it partially twenty-six years ago. It differs from the French in distinctness and expedition, as the intelligence is not conveyed alphabetically....

I intended to detail my telegraphs (in the plural), but I find that I have not room at present. If you think it worth while, you shall have the whole scheme before you, which I know you will improve for me. Suffice it, that by day, at eighteen or twenty miles' distance, I show, by four pointers, isosceles triangles, twenty feet high, on four imaginary circles, eight imaginary points, which correspond with the figures

0, 1, 2, 3, 4, 5, 6, 7.

So that seven thousand different combinations are formed, of four figures each, which refer to a dictionary of words that are referred to,—of lists of the navy, army, militia, lords, commons, geographical and technical terms, &c., besides an alphabet. So that everything one wishes may be transmitted with expedition.

By night, white lights are used.

Dr. Darwin to Mr. Edgeworth.

Derby, March 15, 1795.    

Dear Sir,—I beg your pardon for not immediately answering your last favor, which was owing to the great influence the evil demon has at present in all affairs on this earth. That is, I lost your letter, and have in vain looked over some scores of papers, and cannot find it. Secondly, having lost your letter, I daily hoped to find it again—without success.

The telegraph you described I dare say would answer the purpose. It would be like a giant wielding his long arms and talking with his fingers; and those long arms might be covered with lamps in the night. You would place four or six such gigantic figures in a line, so that they should spell a whole word at once; and other such figures in sight of each other, all round the coast of Ireland; and thus fortify yourselves, instead of Friar Bacon's wall of brass round England, with the brazen head, which spoke, "Time is! Time was! Time is past!"

MR. EDGEWORTH'S MACHINE.

Having slightly mentioned the contrivances made use of by the ancients for conveying intelligence swiftly, and having pointed out some of the various important uses to which this art may be applied, I shall endeavor to give a clear view of my attempts on this subject.

Models of the French telegraph have been so often exhibited, and the machine itself is so well known, that it is not necessary to describe it minutely in this place. It is sufficient to say that it consists of a tall pole, with three movable arms, which may be seen at a considerable distance through telescopes; these arms may be set in as many different positions as are requisite to express all the different letters of the alphabet. By a successive combination of letters shown in this manner, words and sentences are formed and intelligence communicated. No doubt can be made of the utility of this machine, as it has been applied to the most important purposes. It is obviously liable to mistakes, from the number of changes requisite for each word, and from the velocity with which it must be moved to convey intelligence with any tolerable expedition.

The name, however, which is well chosen, has become so familiar, that I shall, with a slight alteration, adopt it for the apparatus which I am going to describe. Telegraph is a proper name for a machine which describes at a distance. Telelograph, or contractedly Tellograph, is a proper name for a machine that describes words at a distance.

Dr. Hooke, to whom every mechanic philosopher must recur, has written an essay upon the subject of conveying swift intelligence, in which he proposes to use large wooden letters in succession. The siege of Vienna turned his attention to the business. His method is more cumbrous than the French telegraph, but far less liable to error.

I tried it before I had seen Hooke's work, in the year 1767 in London, and I could distinctly read letters illuminated with lamps in Hampstead Churchyard, from the house of Mr. Elers in Great Russell Street, Bloomsbury, to whom I refer for date and circumstance. To him and to Mr. E. Delaval, F.R.S., to Mr. Perrot, of Hare Hatch, and to Mr Woulfe the chemist, I refer for the precedency which I claim in this invention. In that year I invented the idea of my present tellograph, proposing to make use of windmill sails instead of the hands or pointers which I now employ. Mr. Perrot was so good as to accompany me more than once to a hill near his house to observe with a telescope the windmill at Nettlebed, which places are, I think, sixteen miles asunder. My intention at that time was to convey not only a swift but an unsuspected mode of intelligence. By means of common windmills this might have been effected, before an account of the French telegraph was made public.

My machinery consists of four triangular pointers or hands [each upon a separate pedestal, ranged along in a row], each of which points like the hand of a clock to different situations in the circles which they describe. It is easy to distinguish whether a hand moving vertically points perpendicularly downwards or upwards, horizontally to the right or left, or to any of the four intermediate positions.

The eye can readily perceive the eight different positions in which one of the pointers is represented [on the plate attached to the article in the "Transactions," but here omitted]. Of these eight positions seven only are employed to denote figures, the upright position of the hand or pointer being reserved to represent o, or zero. The figures thus denoted refer to a vocabulary in which all the words are numbered. Of the four pointers, that which appears to the left hand of the observer represents thousands; the others hundreds, tens, and units, in succession, as in common numeration.

[By these means, as Mr. Edgeworth showed, numbers from 1 up to 7,777, omitting those having a digit above 7, could be displayed to the distant observer, who on referring to his vocabulary discovered that they meant such expressions as it might seem convenient to transmit by this excellent invention.]

Although the electric telegraphs have long since superseded telegraphs of this class in public use, the young people of Colonel Ingham's class took great pleasure in the next summer in using Mr. Edgeworth's telegraph to communicate with each other, by plans easily made in their different country homes.

It may interest the casual reader to know that the first words in the first message transmitted on the telegraph between Scotland and Ireland, alluded to above, were represented by the numbers 2,645, 2,331, 573, 1,113 244, 2,411, 6,336, which being interpreted are,—

"Hark from basaltic rocks and giant walls,"

and so on with the other lines, seven in number. This is Mr. Edgeworth's concise history of telegraphy before his time.

The art of conveying intelligence by sounds and signals is of the highest antiquity. It was practised by Theseus in the Argonautic expedition, by Agamemnon at the siege of Troy, and by Mardonius in the time of Xerxes. It is mentioned frequently in Thucydides. It was used by Tamerlane, who had probably never heard of the black sails of Theseus; by the Moors in Spain; by the Welsh in Britain; by the Irish; and by the Chinese on that famous wall by which they separated themselves from Tartary.

All this detail about Mr. Edgeworth's telegraph resulted in much search in the older encyclopædias. Quite full accounts were found, by the young people, of his system, and of the French system afterwards employed, and worked in France until the electric telegraph made all such inventions unnecessary.

Before the next meeting, Bedford Long, who lived on Highland Street in Roxbury, and Hugh, who lived on the side of Corey Hill, were able to communicate with each other by semaphore; and at the next meeting they arranged two farther stations, so that John, at Cambridge, and Jane Fortescue, at Lexington, were in the series.

There being some half an hour left that afternoon, the children amused themselves by looking up some other of Mr. Edgeworth's curious experiments and vagaries.

MORE OF MR. EDGEWORTH'S FANCIES.

During my residence at Hare Hatch another wager was proposed by me among our acquaintance, the purport of which was that I undertook to find a man who should, with the assistance of machinery, walk faster than any other person that could be produced. The machinery which I intended to employ was a huge hollow wheel, made very light, withinside of which, in a barrel of six feet diameter, a man should walk. Whilst he stepped thirty inches, the circumference of the large wheel, or rather wheels, would revolve five feet on the ground; and as the machinery was to roll on planks and on a plane somewhat inclined, when once the vis inertiæ of the machine should be overcome, it would carry on the man within it as fast as he could possibly walk. I had provided means of regulating the motion, so that the wheel should not run away with its master. I had the wheel made; and when it was so nearly completed as to require but a few hours' work to finish it, I went to London for Lord Effingham, to whom I had promised that he should be present at the first experiment made with it. But the bulk and extraordinary appearance of my machine had attracted the notice of the country neighborhood; and, taking advantage of my absence, some idle curious persons went to the carpenter I employed, who lived on Hare Hatch Common. From him they obtained the great wheel which had been left by me in his care. It was not finished. I had not yet furnished it with the means of stopping or moderating its motion. A young lad got into it; his companions launched it on a path which led gently down hill towards a very steep chalk-pit. This pit was at such a distance as to be out of their thoughts when they set the wheel in motion. On it ran. The lad withinside plied his legs with all his might. The spectators, who at first stood still to behold the operation, were soon alarmed by the shouts of their companion, who perceived his danger. The vehicle became quite ungovernable; the velocity increased as it ran down hill. Fortunately the boy contrived to jump from his rolling prison before it reached the chalk-pit; but the wheel went on with such velocity as to outstrip its pursuers, and, rolling over the edge of the precipice, it was dashed to pieces.

The next day, when I came to look for my machine, intending to try it on some planks which had been laid for it, I found, to my no small disappointment, that the object of all my labors and my hopes was lying at the bottom of a chalk-pit, broken into a thousand pieces. I could not at that time afford to construct another wheel of this sort, and I cannot therefore determine what might have been the success of my scheme.

As I am on the subject of carriages, I shall mention a sailing-carriage that I tried on this common. The carriage was light, steady, and ran with amazing velocity. One day, when I was preparing for a sail in it with my friend and schoolfellow Mr. William Foster, my wheel-boat escaped from its moorings just as we were going to step on board. With the utmost difficulty I overtook it; and as I saw three or four stage-coaches on the road, and feared that this sailing-chariot might frighten their horses, I, at the hazard of my life, got into my carriage while it was under full sail, and then, at a favorable part of the road, I used the means I had of guiding it easily out of the way. But the sense of the mischief which must have ensued if I had not succeeded in getting into the machine at the proper place and stopping it at the right moment was so strong as to deter me from trying any more experiments on this carriage in such a dangerous place.

Such should never be attempted except on a large common, at a distance from a high road. It may not, however, be amiss to suggest that upon a long extent of iron railway in an open country carriages properly constructed might make profitable voyages, from time to time, with sails instead of horses; for though a constant or regular intercourse could not be thus carried on, yet goods of a certain sort, that are salable at any time, might be stored till wind and weather were favorable.

When Bedford had read this passage, John Fordyce said he had travelled hundreds of miles on the Western railways where Mr. Edgeworth's sails could have been applied without a "stage-coach" to be afraid of them.

JACK THE DARTER.

In one of my journeys from Hare Hatch to Birmingham, I accidentally met with a person whom I, as a mechanic, had a curiosity to see. This was a sailor, who had amused London with a singular exhibition of dexterity. He was called Jack the Darter. He threw his darts, which consisted of thin rods of deal of about half an inch in diameter and of a yard long, to an amazing height and distance; for instance, he threw them over what was then called the New Church in the Strand. Of this feat I had heard, but I entertained some doubts upon the subject. I had inquired from my friends where this man could be found, but had not been able to discover him. As I was driving towards Birmingham in an open carriage of a singular construction, I overtook a man who walked remarkably fast, but who stopped as I passed him, and eyed my equipage with uncommon curiosity. There was something in his manner that made me speak to him; and from the sort of questions he asked about my carriage, I found that he was a clever fellow. I soon learned that he had walked over the greatest part of England, and that he was perfectly acquainted with London. It came into my head to inquire whether he had ever seen the exhibition about which I was so desirous to be informed.

"Lord! sir," said he, "I am myself Jack the Darter." He had a roll of brown paper in his hand, which he unfolded, and soon produced a bundle of the light deal sticks which he had the power of darting to such a distance. He readily consented to gratify my curiosity; and after he had thrown some of them to a prodigious height, I asked him to throw some of them horizontally. At the first trial he threw one of them eighty yards with great ease. I observed that he coiled a small string round the stick, by which he gave it a rotary motion that preserved it from altering its course; and at the same time it allowed the arm which threw it time to exercise its whole force.

If anything be simply thrown from the hand, it is clear that it can acquire no greater velocity than that of the hand that throws it; but if the body that is thrown passes through a greater space than the hand, whilst the hand continues to communicate motion to the body to be impelled, the body will acquire a velocity nearly double to that of the hand which throws it. The ancients were aware of this; and they wrapped a thong of leather round their javelins, by which they could throw them with additional violence. This invention did not, I believe, belong to the Greeks; nor do I remember its being mentioned by Homer or Xenophon. It was in use among the Romans, but at what time it was introduced or laid aside I know not. Whoever is acquainted with the science of projectiles will perceive that this invention is well worthy of their attention.

A ONE-WHEELED CHAISE.

After having satisfied my curiosity about Jack the Darter, I proceeded to Birmingham. I mentioned that I travelled in a carriage of a singular construction. It was a one-wheeled chaise, which I had had made for the purpose of going conveniently in narrow roads. It was made fast by shafts to the horse's sides, and was furnished with two weights or counterpoises, that hung below the shafts. The seat was not more than eight and twenty or thirty inches from the ground, in order to bring the centre of gravity of the whole as low as possible. The footboard turned upon hinges fastened to the shafts, so that when it met with any obstacle it gave way, and my legs were warned to lift themselves up. In going through water my legs were secured by leathers, which folded up like the sides of bellows; by this means I was pretty safe from wet. On my road to Birmingham I passed through Long Compton, in Warwickshire, on a Sunday. The people were returning from church, and numbers stopped to gaze at me. There is, or was, a shallow ford near the town, over which there was a very narrow bridge for horse and foot passengers, but not sufficiently wide for wagons or chaises. Towards this bridge I drove. The people, not perceiving the structure of my one-wheeled vehicle, called to me with great eagerness to warn me that the bridge was too narrow for carriages. I had an excellent horse, which went so fast as to give but little time for examination. The louder they called, the faster I drove; and when I had passed the bridge, they shouted after me with surprise. I got on to Shipstone upon Stone; but before I had dined there I found that my fame had overtaken me. My carriage was put into a coach-house, so that those who came from Long Compton, not seeing it, did not recognize me. I therefore had an opportunity of hearing all the exaggerations and strange conjectures which were made by those who related my passage over the narrow bridge. There were posts on the bridge, to prevent, as I suppose, more than one horseman from passing at once. Some of the spectators asserted that my carriage had gone over these posts; others said that it had not wheels, which was indeed literally true; but they meant to say that it was without any wheel. Some were sure that no carriage ever went so fast; and all agreed that at the end of the bridge, where the floods had laid the road for some way under water, my carriage swam on the surface of the water.

VIII.

JAMES WATT.

"Mabel, my child," said Uncle Fritz, "you talk like a book, and a very interesting one at that; but I think, as the youngest of us would say, that you are just a little off in your remarks. And as I observe that Clem, who is going to read this afternoon, desires to deliver a sermon of which your conversation seems to be the text, I will request all to listen to him before we consider seriously vacating this apartment, however poor it may be,"—and he glanced fondly around at the comfortable arrangements that everywhere pervaded the study,—"and seek the regions below."

"I only wanted to say," began Clem, "that although Watt did on one occasion (in his extreme youth) look at a teakettle with some interest, he was not in the habit, at the time when he devoted most thought to the steam-engine, of having a teakettle continually before him that he might gain inspiration from observing the steam issue from its nose. And, as Watt dispensed with this aid, I have no doubt that we may do so as well, contenting ourselves with the results of the experiments in the vaporization of water, which Ellen is now conducting in the form of tea. Besides all this, however, I do want to say some things, before we read aloud this afternoon (I hope this isn't really too much like a sermon), about the steam-engine and the part that Watt had in perfecting it."

At this point the irrepressible Mabel was heard to whisper to Bedford, who sat next her: "Wasn't it curious that the same mind which grasped the immense capabilities of the steam-engine should have been able also to construct such a delicate lyric as

'How doth the little busy bee
Improve each shining hour'?"

"Mabel," said Colonel Ingham, "you are absolutely unbearable. If you do not keep in better order I shall be sorry that I dissuaded you from descending to the kitchen. I see nothing incongruous myself in indulging in mechanical experiments, and in throwing one's thoughts into the form of verse,"—here the old gentleman colored slightly, as though he recollected something of the sort,—"but it may be well to counteract the impression your conversation may have made by stating that Isaac Watts did not invent the steam-engine, nor did James Watt write the beautiful words you have just quoted.—Now, Clem, I believe you have the floor."

"Well," said Clem, "I only want the floor for a short time in order to explain about Watt and the steam-engine, and how much he was the inventor of it, before we begin to read.

"There are various points about the steam-engine which are really Watt's invention,—the separate condenser, for instance,—but the idea of the steam-engine was not original with him; that is, when he saw the steam in the teakettle raise the lid and drop it again, he was not the first to speculate on the power of steam."

"Are you going to read us that part in the book, Clem?" asked Bedford, with some interest.

"Yes, if you like," said Clem. "I guess it tells about it in Mr. Smiles's 'Life of Watt.'" So he began to overhaul the book he had brought, and shortly discovered the anecdote referred to by Mabel with such interest, and read it.

"On one occasion he [James Watt] was reproved by Mrs. Muirhead, his aunt, for his indolence at the tea-table. 'James Watt,' said the worthy lady, 'I never saw such an idle boy as you are. Take a book, or employ yourself usefully; for the last hour you have not spoken one word, but taken off the lid of that kettle and put it on again, holding now a cup and now a silver spoon over the steam, watching how it rises from the spout, catching and counting the drops it falls into.' In the view of M. Arago, the little James before the teakettle, becomes the great engineer, preparing the discoveries which were soon to immortalize him. In our opinion, the judgment of the aunt was the truest. There is no reason to suppose that the mind of the boy was occupied with philosophical theories on the condensation of steam, which he compassed with so much difficulty in his maturer years. This is more probably an afterthought borrowed from his subsequent discoveries. Nothing is commoner than for children to be amused with such phenomena in the same way that they will form air-bubbles in a cup of tea, and watch them sailing over the surface till they burst. The probability is that little James was quite as idle as he seemed."

"That is very interesting," remarked Mabel. "Don't you think now, Uncle Fritz, we had better go into the kitchen?" And she looked appealingly at the old gentleman, who merely held up his finger for silence as Clem continued his lecture.

"What I meant to say," Clem went on, "was that other people before Watt had found out the power of steam, and had used it too. There was one Hero of Alexandria, who lived about two thousand years ago, who used steam for many interesting purposes, notably for animating various figures that took part in the idolatrous worship of his time, and thus in deceiving the common people. But his contrivances, though engines which went by steam, would hardly be called steam-engines. Between Hero of Alexandria, of 160 b. c., and the Marquis of Worcester, of 1650 a. d., there does not seem to have been much doing in the way of inventing the steam-engine. But the Marquis of Worcester in Charles II.'s time was a great philosopher, and did nobody knows exactly what with steam. But though he did great things, he did not produce a particularly capable engine, though he seems to have known more about steam than anybody else did at his time. After the Marquis of Worcester and before Watt, there were three men who did much towards inventing and improving the steam-engine. Their names were Savery, Papin, and Newcomen. I don't propose to tell you about the inventions of each one; but it's well enough to remember that each one did important service in getting the steam-engine to the point where Watt took hold of it. As it was on Newcomen's engine that Watt made his first serious experiments, I think we should all like to know something about it."

THE NEWCOMEN ENGINE.

Newcomen's engine may be thus briefly described: The steam was generated in a separate boiler, as in Savery's engine, from which it was conveyed into a vertical cylinder underneath a piston fitting it closely, but movable upwards and downwards through its whole length. The piston was fixed to a rod, which was attached by a joint or chain to the end of a lever vibrating upon an axis, the other end being attached to a rod working a pump. When the piston in the cylinder was raised, steam was let into the vacated space through a tube fitted into the top of the boiler, and mounted with a stopcock. The pump-rod at the further end of the lever being thus depressed, cold water was applied to the sides of the cylinder, on which the steam within it was condensed, a vacuum was produced, and the external air, pressing upon the top of the piston, forced it down into the empty cylinder. The pump-rod was thereby raised; and, the operation of depressing it being repeated, a power was thus produced which kept the pump continuously at work. Such, in a few words, was the construction and action of Newcomen's first engine.[8]

While the engine was still in its trial state, a curious accident occurred which led to a change in the mode of condensation, and proved of essential importance in establishing Newcomen's engine as a practical working power. The accident was this: in order to keep the cylinder as free from air as possible, great pains were taken to prevent it passing down by the side of the piston, which was carefully wrapped with cloth or leather; and, still further to keep the cylinder air-tight, a quantity of water was kept constantly on the upper side of the piston. At one of the early trials the inventors were surprised to see the engine make several strokes in unusually quick succession; and on searching for the cause, they found it to consist in a hole in the piston, which had let the cold water in a jet into the inside of the cylinder, and thereby produced a rapid vacuum by the condensation of the continued steam. A new light suddenly broke upon Newcomen. The idea of condensing by injection of cold water directly into the cylinder, instead of applying it on the outside, at once occurred to him; and he proceeded to embody the expedient which had thus been accidentally suggested as part of his machine. The result was the addition of the injection pipe, through which, when the piston was raised and the cylinder full of steam, a jet of cold water was thrown in, and, the steam being suddenly condensed, the piston was at once driven down by the pressure of the atmosphere.

An accident of a different kind shortly after led to the improvement of Newcomen's engine in another respect. To keep it at work, one man was required to attend the fire, and another to turn alternately the two cocks, one admitting the steam into the cylinder, the other admitting the jet of cold water to condense it. The turning of these cocks was easy work, usually performed by a boy. It was, however, a very monotonous duty, though requiring constant attention. To escape the drudgery and obtain an interval for rest or perhaps for play, a boy named Humphrey Potter, who turned the cocks, set himself to discover some method of evading his task. He must have been an ingenious boy, as is clear from the arrangement he contrived with this object. Observing the alternate ascent and descent of the beam above his head, he bethought him of applying the movement to the alternate raising and lowering of the levers which governed the cocks. The result was the contrivance of what he called the scoggan (meaning presumably the loafer or lazy boy), consisting of a catch worked by strings from the beam of the engine. This arrangement, when tried, was found to answer the purpose intended. The action of the engine was thus made automatic; and the arrangement, though rude, not only enabled Potter to enjoy his play, but it had the effect of improving the working power of the engine itself; the number of strokes which it made being increased from six or eight to fifteen or sixteen in the minute. This invention was afterward greatly improved by Mr. Henry Beighton, of Newcastle-on-Tyne, who added the plug-rod and hand-gear. He did away with the catches and strings of the boy Potter's rude apparatus, and substituted a rod suspended from the beam, which alternately opened and shut the tappets attached to the steam and injection cocks.

Thus, step by step, Newcomen's engine grew in power and efficiency, and became more and more complete as a self-acting machine. It will be observed that, like all other inventions, it was not the product of any one man's ingenuity, but of many. One contributed one improvement, and another another. The essential features of the atmospheric engine were not new. The piston and cylinder had been known as long ago as the time of Hero. The expansive force of steam and the creation of a vacuum by its condensation had been known to the Marquis of Worcester, Savery, Papin, and many more. Newcomen merely combined in his machine the result of their varied experience; and, assisted by the persons who worked with him, down to the engine-boy Potter, he advanced the invention several important stages; so that the steam-engine was no longer a toy or a scientific curiosity, but had become a powerful machine capable of doing useful work.

JAMES WATT AND THE STEAM-ENGINE.

It was in the year 1759 that Robison[9] first called the attention of his friend Watt to the subject of the steam-engine. Robison was then only in his twentieth, and Watt in his twenty-third year. Robison's idea was that the power of steam might be advantageously applied to the driving of wheel-carriages; and he suggested that it would be the most convenient for the purpose to place the cylinder with its open end downwards to avoid the necessity of using a working-beam. Watt admits that he was very ignorant of the steam-engine at the time; nevertheless, he began making a model with two cylinders of tin plate, intending that the pistons and their connecting-rods should act alternately on two pinions attached to the axles of the carriage-wheels. But the model, being slightly and inaccurately made, did not answer his expectations. Other difficulties presented themselves, and the scheme was laid aside because Robison left Glasgow to go to sea. Indeed, mechanical science was not yet ripe for the locomotive. Robison's idea had, however, dropped silently into the mind of his friend, where it grew from day to day, slowly and at length fruitfully.

At his intervals of leisure and in the quiet of his evenings, Watt continued to prosecute his various studies. He was shortly attracted by the science of chemistry, then in its infancy. Dr. Black was at that time occupied with the investigations which led to his discovery of the theory of latent heat, and it is probable that his familiar conversations with Watt on the subject induced the latter to enter upon a series of experiments with the view of giving the theory some practical direction. His attention again and again reverted to the steam-engine, though he had not yet seen even a model of one. Steam was as yet almost unknown in Scotland as a working power. The first engine was erected at Elphinstone Colliery, in Stirlingshire, about the year 1750; and the second more than ten years later, at Govan Colliery, near Glasgow, where it was known by the startling name of "The Firework." This had not, however, been set up at the time Watt had begun to inquire into the subject. But he found that the college possessed the model of a Newcomen engine for the use of the Natural Philosophy class, which had been sent to London for repair. On hearing of its existence, he suggested to his friend Dr. Anderson, Professor of Natural Philosophy, the propriety of getting back the model; and a sum of money was placed by the Senatus at the professor's disposal, "to recover the steam-engine from Mr. Sisson, instrument-maker in London."

In the mean time Watt sought to learn all that had been written on the subject of the steam-engine. He ascertained from Desaguliers, Switzer, and other writers, what had been accomplished by Savery, Newcomen, Beighton, and others; and he went on with his own independent experiments. His first apparatus was of the simplest possible kind. He used common apothecaries' phials for his steam reservoirs, and canes hollowed out for his steam-pipes. In 1761 he proceeded to experiment on the force of steam by means of a small Papin's digester and a syringe. The syringe was only the third of an inch in diameter, fitted with a solid piston; and it was connected with the digester by a pipe furnished with a stopcock, by which the steam was admitted or shut off at will. It was also itself provided with a stopcock, enabling a communication to be opened between the syringe and the outer air to permit the steam in the syringe to escape. The apparatus, though rude, enabled the experimenter to ascertain some important facts. When the steam in the digester was raised and the cock turned, enabling it to rush against the lower side of the piston, he found that the expansive force of the steam raised a weight of fifteen pounds, with which the piston was loaded. Then on turning on the cock and shutting off the connection with the digester at the same time that a passage was opened to the air, the steam was allowed to escape, when the weight upon the piston, being no longer counteracted, immediately forced it to descend.

Watt saw that it would be easy to contrive that the cocks should be turned by the machinery itself with perfect regularity. But there was an objection to this method. Water is converted into vapor as soon as its elasticity is sufficient to overcome the weight of the air which keeps it down. Under the ordinary pressure of the atmosphere water acquires this necessary elasticity at 212°; but as the steam in the digester was prevented from escaping, it acquired increased heat, and by consequence increased elasticity. Hence it was that the steam which issued from the digester was not only able to support the piston and the air which pressed upon its upper surface, but the additional load with which the piston was weighted. With the imperfect mechanical construction, however, of those days, there was a risk lest the boiler should be burst by the steam, which was apt to force its way through the ill-made joints of the machine. This, conjoined with the great expenditure of steam on the high-pressure system, led Watt to abandon the plan; and the exigencies of his business for a time prevented him from pursuing his experiments.

At length the Newcomen model arrived from London; and in 1763 the little engine, which was destined to become so famous, was put into the hands of Watt. The boiler was somewhat smaller than an ordinary teakettle. The cylinder of the engine was only of two inches diameter and six inches stroke. Watt at first regarded it as merely "a fine plaything." It was, however, enough to set him upon a track of thinking which led to the most important results. When he had repaired the model and set it to work, he found that the boiler, though apparently large enough, could not supply steam in sufficient quantity, and only a few strokes of the piston could be obtained, when the engine stopped. The fire was urged by blowing, and more steam was produced; but still it would not work properly. Exactly at the point at which another man would have abandoned the task in despair, the mind of Watt became thoroughly roused. "Everything," says Professor Robison, "was to him the beginning of a new and serious study; and I knew that he would not quit it till he had either discovered its insignificance or had made something of it." Thus it happened with the phenomena presented by the model of the steam-engine. Watt referred to his books, and endeavored to ascertain from them by what means he might remedy the defects which he found in the model; but they could tell him nothing. He then proceeded with an independent course of experiments, resolved to work out the problem for himself. In the course of his inquiries he came upon a fact which, more than any other, led his mind into the train of thought which at last conducted him to the invention of which the results were destined to prove so stupendous. This fact was the existence of latent heat.

In order to follow the track of investigation pursued by Watt, it is necessary for a moment to revert to the action of the Newcomen pumping-engine. A beam, moving upon a centre, had affixed to one end of it a chain attached to the piston of the pump, and at the other a chain attached to a piston that fitted into the steam-cylinder. It was by driving this latter piston up and down the cylinder that the pump was worked. To communicate the necessary movement to the piston, the steam generated in a boiler was admitted to the bottom of the cylinder, forcing out the air through a valve, where its pressure on the under side of the piston counterbalanced the pressure of the atmosphere on its upper side. The piston, thus placed between two equal forces, was drawn up to the top of the cylinder by the greater weight of the pump-gear at the opposite extremity of the beam. The steam, so far, only discharged the office of the air it displaced; but if the air had been allowed to remain, the piston once at the top of the cylinder could not have returned, being pressed as much by the atmosphere underneath as by the atmosphere above it. The steam, on the contrary, which was admitted by the exclusion of air, could be condensed, and a vacuum created, by injecting cold water through the bottom of the cylinder. The piston, being now unsupported, was forced down by the pressure of the atmosphere on its upper surface. When the piston reached the bottom, the steam was again let in, and the process was repeated. Such was the engine in ordinary use for pumping water at the time that Watt began his investigations.

Among his other experiments, he constructed a boiler which showed by inspection the quantity of water evaporated in any given time, and the quantity of steam used in every stroke of the engine. He was astonished to discover that a small quantity of water in the form of steam heated a large quantity of cold water injected into the cylinder for the purpose of cooling it; and upon further examination he ascertained that steam heated six times its weight of cold water to 212°, which was the temperature of the steam itself. "Being struck with this remarkable fact," says Watt, "and not understanding the reason of it, I mentioned it to my friend Dr. Black, who then explained to me his doctrine of latent heat, which he had taught for some time before this period (the summer of 1764); but having myself been occupied by the pursuits of business, if I had heard of it I had not attended to it, when I thus stumbled upon one of the material facts by which that beautiful theory is supported."

When Watt found that water in its conversion into vapor became such a reservoir of heat, he was more than ever bent on economizing it; for the great waste of heat involving so heavy a consumption of fuel was felt to be the principal obstacle to the extended employment of steam as a motive power. He accordingly endeavored, with the same quantity of fuel, at once to increase the production of steam and to diminish its waste. He increased the heating surface of the boiler by making flues through it; he even made his boiler of wood, as being a worse conductor of heat than the brickwork which surrounds common furnaces; and he cased the cylinders and all the conducting pipes in materials which conducted heat very slowly. But none of these contrivances were effectual; for it turned out that the chief expenditure of steam, and consequently of fuel, in the Newcomen engine, was occasioned by the reheating of the cylinder after the steam had been condensed, and the cylinder was consequently cooled by the injection into it of the cold water. Nearly four fifths of the whole steam employed was condensed on its first admission, before the surplus could act upon the piston. Watt therefore came to the conclusion that to make a perfect steam-engine it was necessary that the cylinder should be always as hot as the steam that entered it; but it was equally necessary that the steam should be condensed when the piston descended, nay, that it should be cooled down below 100°, or a considerable amount of vapor would be given off, which would resist the descent of the piston, and diminish the power of the engine. Thus the cylinder was never to be at a less temperature than 212°, and yet at each descent of the piston it was to be less than 100°,—conditions which, on the very face of them, seemed to be wholly incompatible.

Though still occupied with his inquiries and experiments as to steam, Watt did not neglect his proper business, but was constantly on the look-out for improvements in instrument-making. A machine which he invented for drawing in perspective proved a success; and he made a considerable number of them to order, for customers in London as well as abroad. He was also an indefatigable reader, and continued to extend his knowledge of chemistry and mechanics by perusal of the best books on these sciences.

Above all subjects, however, the improvement of the steam-engine continued to keep the fastest hold upon his mind. He still brooded over his experiments with the Newcomen model, but did not seem to make much way in introducing any practical improvement in its mode of working. His friend Robison says he struggled long to condense with sufficient rapidity without injection, trying one experiment after another, finding out what would not do, and exhibiting many beautiful specimens of ingenuity and fertility of resource. He continued, to use his own words, "to grope in the dark, misled by many an ignis fatuus." It was a favorite saying of his that "Nature has a weak side, if we can only find it out;" and he went on groping and feeling for it, but as yet in vain. At length light burst upon him, and all at once the problem over which he had been brooding was solved.