The principal men of business in Glasgow at the time of which we speak were the tobacco lords—importers of that article from the plantations in Virginia,[60]—who were often to be seen strutting along the Plainstanes, dressed in scarlet cloaks, cocked hats, and powdered wigs; the “boddies” who kept the adjoining shops eying them over their half-closed doors, and humbly watching for a nod of recognition from the mighty potentates. Yet even the greatest of the tobacco lords only lived in flats, entering from a common stair; and the domestic accommodation was so scanty and so primitive, that visitors were of necessity received in the bedrooms. This circumstance seems to have had some influence in the formation of the Clubs,[61] which then formed a curious feature of society in most Scotch towns. They consisted of knots of men of like tastes and pursuits, who met in the evenings at public-houses for purposes of gossip and social drinking. There they made new and cultivated old acquaintanceships, and exchanged news with each other. The Club combined the uses of the newspaper and the newsroom, which now accomplish the same objects without the drinking. But Glasgow had then no newspaper; and a London news-sheet of a week old was looked upon as a novelty. There was no coffee-room nor public library in the town; no theatre[62] nor place of resort open, except the “Change-house;” so that the Club was regarded as a social necessity. The drinking was sometimes moderate, and sometimes “hard.” The better class confined themselves to claret and other French wines, which were then cheap, being free from duty. Those disposed to indulge in more frugal fare confined themselves to oat-cake and small-beer. It was not until heavy taxes were laid on foreign wines and malt that the hard whisky-drinking of Scotland set in. Whisky was introduced from the Highlands shortly after the “Forty-five;” and it soon became the popular drink. By 1780 the drinking of raw whisky in Glasgow at midday had become general.[63]

When young Watt arrived in Glasgow he carried with him but a small quantity of baggage; the articles in his trunk including amongst other things a quadrant,—probably a specimen of his own handiwork,—a leather apron, about a score of carpenters’ and other tools, and “a pair of bibels.” On making inquiry for a proper master, under whom to learn the business of mathematical instrument making, it was found that there was no such person in Glasgow. There was, however, a mechanic in the town, who dignified himself with the name of “optician,” under whom Watt was placed for a time. He was a sort of Jack-of-all-trades, who sold and mended spectacles, repaired fiddles, tuned spinets, made and repaired the simpler instruments used in mechanical drawing, and eked out a slender living by making and selling fishing-rods and fishing-tackle. Watt was as handy at dressing trout and salmon flies as at most other things, and his master, no doubt, found him useful enough; but there was nothing to be learnt in return for his services. Though his master was an ingenious workman, in a small way, and could turn his ready hand to anything, it soon became clear to Watt’s relations, the Muirheads, with whom he lived during his stay, that the instructions of such an artist were little likely to advance him in mathematical instrument making. Among the gentlemen to whom Watt was introduced by his relatives was Dr. Dick, Professor of Natural Philosophy in Glasgow College, who strongly recommended him to proceed to London, and there place himself under the instruction of some competent master. Watt consulted his father on the subject, who readily gave his sanction to the proposal; and, with a letter of introduction from Dr. Dick in his pocket, he set out for the great city accordingly.

No stage-coach then ran between Glasgow and London; so it was determined that young Watt should proceed on horseback, then the most convenient and speedy mode of travelling. His chest was sent by sea. Old Mr. Watt’s memorandum-book at Heathfield contains the following entry, under date the 6th June, 1755:—

The “plaster and pomet” may possibly have been provided in view of the long journey on horseback and its contingencies. It was arranged that the youth should travel in the company of a relative, Mr. Marr, a sea-captain, who was on his way to join his ship, then lying in the Thames. They set out on the 7th of June, travelling by way of Coldstream and Newcastle, where they joined the great north road, then comparatively practicable to the south of Durham. They reached London safely on the 19th, having been about a fortnight on the road.

Mr. Marr immediately proceeded to make inquiries for a mathematical instrument maker with whom to place his young friend. But it was found that a serious obstacle presented itself in the rules of the trade, which prescribed that those employed must either be apprentices serving under a seven years’ apprenticeship, or, if journeymen, that they should have served for that term. Watt, however, had no intention of binding himself to serve for so long a period, and he had no pretensions to rank as a journeyman. His object was to learn the business in the shortest possible time, and then return to Glasgow and set up for himself. The two went about from shop to shop, but only met with rebuffs. “I have not yet got a master,” Watt wrote to his father about a fortnight after his arrival; “we have tried several, but they all made some objection or other. I find that, if any of them agree with me at all, it will not be for less than a year; and even for that time they will be expecting some money.”

Mr. Marr continued to exert himself on behalf of the youth. Anxious to be employed in any way rather than not at all, Watt offered his services gratuitously to a watchmaker named Neale, with whom Mr. Marr did business, and he was allowed to occupy himself in his shop for a time, cutting letters and figures in metal. At length a situation of a more permanent character was obtained for him; and he entered the shop of Mr. John Morgan, a respectable mathematical instrument maker in Cornhill, on the terms of receiving a year’s instruction in return for a fee of twenty guineas and the proceeds of his labour during that time. He soon proved himself a ready learner and skilful workman. That division of labour, the result of an extensive trade, which causes the best London carriages to be superior to any of provincial construction, was even then applied to mathematical instruments. “Very few here,” wrote Watt, “know any more than how to make a rule, others a pair of dividers, and such like.” His first employment was in making brass scales, rules, parallels, and the brass-work of quadrants; and by the end of a month he was able to finish a Hadley’s quadrant in better style than any apprentice in the shop. From rule and quadrant making he proceeded to azimuth compasses, brass sectors, theodolites, and the more delicate kinds of instruments. At the end of the year he wrote home to his father that he had made “a brass sector with a French joint, which is reckoned as nice a piece of framing-work as is in the trade;” and he expressed the hope that he would soon be able to work for himself, and earn his bread by his own industry.

Up to this time he had necessarily been maintained by his father, on whom he drew from time to time. Mr. Watt’s memorandum-books show that on the 27th of June he remitted him 10l.; on the 24th of August following he enters: “Sent George Anderson by post 8l. to buy a bill of 7l. or 8l. to send Wheytbread and Gifferd, and ballance of my son’s bill, 2l. 2s. 3d., for which ame to remite him more;” and on the 11th September following, the balance was forwarded through the same channel. On the 24th October, 4l. 10s. was in like manner sent to George Anderson “on son James’s second bill;” and on the 31st December, 10l. was remitted, “to be put to the credit of son James’s last bill.” To relieve his father as much as possible for the cost of his maintenance in London, Watt lived in a very frugal style, avoiding all unnecessary expenses. His living cost him only eight shillings a week; and he could not reduce it below that, he wrote to his father, “without pinching his belly.” He also sought for some remunerative work on his own account; and when he could obtain it he sat up at night to execute it.

During Watt’s stay in London he was in a great measure prevented from stirring abroad by the hot press for sailors which was then going on. As many as forty pressgangs were at work, seizing all able-bodied men they could lay hands on. In one night they took not fewer than a thousand men. Nor were the kidnappers idle. These were the agents of the East India Company, who had crimping-houses in different parts of the city for receiving the men whom they had seized upon for service in the Indian army. Even when the demand for soldiers abated, the kidnappers continued their trade, and sold their unhappy victims to the planters in Pennsylvania and other North American colonies. Sometimes severe fights took place between the pressgangs and the kidnappers for possession of those who had been seized, the law and police being apparently powerless to protect them. “They now press anybody they can get,” Watt wrote in the spring of 1756, “landsmen as well as seamen, except it be in the liberties of the city, where they are obliged to carry them before the Lord Mayor first; and unless one be either a prentice or a creditable tradesman, there is scarce any getting off again. And if I was carried before my Lord Mayor, I durst not avow that I wrought in the city, it being against their laws for any unfreeman to work even as a journeyman within the liberties.”[64] What a curious glimpse does this give us into the practice of man-hunting in London in the eighteenth century!

Watt’s enforced confinement, together with his sedentary habits and unremitting labour, soon told upon his weak frame. When he hurried to his lodgings at night, his body was wearied, and his nerves exhausted, so that his hands shook like those of an old man; yet he persevered with the extra work which he imposed upon himself, in order to earn a little honest money to help to pay for his living. His seat in Mr. Morgan’s shop being placed close to the door, which was often opened and shut in the course of the day, he caught a severe cold in the course of the winter; and he was afflicted by a racking cough and severe rheumatic pains, from the effects of which he long continued to suffer. Distressed by a gnawing pain in his back, and greatly depressed in spirits, he at length, with his father’s sanction, determined to return to Greenock, to seek for renewal of health in his native air. His father made him a further remittance to enable him to purchase some of the tools required for his trade, together with materials for making others, and a copy of Bion’s work on the construction and use of Mathematical Instruments. Having secured these, he set out on his return journey for Scotland, and reached Greenock in safety in the autumn of 1756. There his health soon became sufficiently restored to enable him to return to work; and with the concurrence and help of his father, he shortly after proceeded to Glasgow, in his twentieth year, to begin business on his own account.

In endeavouring to establish himself in his trade, Watt encountered the same obstacle which in London had almost prevented his learning it. Although there were no mathematical instrument makers in Glasgow, and it must have been a public advantage to have so skilled a mechanic settled in the place, Watt was opposed by the corporation of hammermen on the ground that he was neither the son of a burgess nor had served an apprenticeship within the borough.[65] Failing in his endeavours to open a place of business, he next tried to prevail on the corporation to allow him to make use of a small workshop wherein to make experiments; but this also was peremptorily refused. The hammermen were doubtless acting in a very narrow spirit, in thus excluding the young mechanic from the privileges of citizenship; but such was the custom of the times,—those who were within the favoured circles usually putting their shoulders together to exclude those who were without. Watt had, however, already been employed by Dr. Dick, Professor of Natural Philosophy, to repair some mathematical instruments which had been bequeathed to the University by a gentleman in the West Indies; and the professors, having an absolute authority within the area occupied by the college buildings, determined to give him an asylum there, and thus free him from the incubus of the guilds.

In the heart of old Glasgow city, not far from the cathedral of St. Mungo, which Knox with difficulty preserved from the fury of the Scotch iconoclasts, stands the venerable University, a curiously black and sombre building, more than 400 years old. Inside the entrance, on the right-hand side, is a stone staircase, guarded by fabulous beasts in stone. The buildings consist of several quadrangles; but there is not much regularity in their design, each part seeming to stand towards the other parts, in a state of independent crookedness and irregularity. There are turrets in the corners of the quadrangles,—turrets with peaked tops, like witches’ caps. In the inner quadrangle, entered from the left-hand side of the outer court, a workshop was found for our mechanician, in which he was securely established by the midsummer of 1757. The apartment appropriated to Watt by the professors is still to be seen in nearly the same rude state in which he left it. It is situated on the first floor of the range of building forming the north-west side of the inner quadrangle, immediately under the gallery of the Natural Philosophy class, with which it communicates. It is lighted by three windows, two of which open into the quadrangle, and the third, at the back, into the Professors’ court. There is a small closet in the corner of the room, where some students have cut their names in the plaster,—date “1713.” The access to the room used to be from the court by a spiral stone staircase; but that entrance is now closed. The apartment is only about twenty feet square; but it served Watt, as it has since served others, for high thinking and noble working.[66]

In addition to his workshop under the Natural Philosophy class, a shop for the sale of his instruments was also appropriated to Watt by the Professors. It formed the ground-floor of the house situated next to the Principal’s Gate, being part of the University Buildings, and was entered directly from the pavement of the High Street. It has been described to us, on the authority of Professor Fleming, as an old house, with a sort of arcade in front, supported on pillars. In making some alterations in the building the pillars were too much weakened, and the house, excepting the basement, had to be taken down. The shop occupied by Watt is the little tenement shown on the right hand of the following engraving; but the lower story of the building has since been altered and repaired, and is now totally different from what it was in Watt’s time.

Though his wants were few, and he lived on humble fare, Watt found it very difficult to earn a subsistence by his trade. His father sent him remittances from time to time; but the old man had suffered serious losses in his own business, and had become much less able to help his son with money. After a year’s trial, Watt wrote to his father, that “unless it be the Hadley’s instruments there is little to be got by it, as at most other jobs I am obliged to do the most of them myself; and, as it is impossible for one person to be expert at everything, they often cost me more time than they should do.” Of the quadrants, he could make three in a week, with the help of a lad; but the profit upon the three was not more than 40s. The customers for these were very few in number, as seagoing ships with their captains could not yet reach Glasgow.[68]

Failing sufficient customers for his instruments, Watt sent those which he had made to Port Glasgow and Greenock, where his father helped him to dispose of them. He also bethought him of taking a journey to Liverpool and London, for the purpose of obtaining orders for instruments; though, for some reason or other—most probably because he was averse to “pushing,” and detested the chaffering of trade—his contemplated journey was not undertaken. He therefore continued to execute only such orders as came to him, so that his business remained very small. He began to fear that he must give up the trade that would not keep him, and he wrote to his father: “If this business does not succeed, I must fall into some other.” To eke out his income, he took to map and chart selling, and, amongst other things, offered for sale the Map of the River Clyde,[69] originally surveyed by his uncle John.

It is well for the world at large that Watt’s maps and quadrants remained on his hands unsold. The most untoward circumstances in life have often the happiest results. It is not Fortune that is blind, but man. Had his instrument-making business prospered, Watt might have become known as a first-class maker of quadrants, but not as the inventor of the condensing steam-engine. It was because his own special business failed that he was driven to betake himself to other pursuits, and eventually to prosecute the invention on which his fame mainly rests. At first he employed part of his leisure in making chemical and other experiments; but as these yielded him no returns in the shape of money, he was under the necessity of making some sort of article that was in demand, and for which he could find customers. Although he had no ear for music, and scarcely knew one note from another, he followed the example of the old spectacle-maker, his first master, in making fiddles, flutes, and guitars, which met with a readier sale than his quadrants. These articles were what artists call “pot-boilers,” and kept him in funds until a maintenance could be earned by higher-class work. We are informed, through a lady at Glasgow, that her father bought a flute from Watt, who said to him, in selling it: “Woe be to ye, Tam, if you’re no guid luck; for this is the first I’ve sold!”

His friend Dr. Black, probably to furnish him with some profitable employment, asked Watt to make a barrel-organ for him, which he at once proceeded to construct. Watt was not the man to refuse work of any kind requiring the exercise of constructive skill. He first carefully studied the principles of harmony,—making science, in a measure, the substitute for want of ear,[70] and took for his guide the profound but obscure work on ‘Harmonics,’ published by Dr. R. Smith of Cambridge. He next made a model of the instrument; after which he constructed the organ, which, when finished, was considered a great success. About the same time the office-bearers of a Mason’s Lodge in Glasgow sent to ask him if he would undertake to build for them a finger-organ. As he had successfully repaired an instrument of the same kind, besides making the barrel-organ, he readily accepted the order. Watt was always, as he said, dissatisfied with other people’s work, as well as his own; and this habit of his mind made him study to improve upon whatever came before him. Thus, in the process of building this organ, he devised a number of novel expedients, such as a sustained monochord, indicators and regulators of the strength of the blast, means of tuning the instrument according to any system of temperament, with sundry contrivances for improving the efficiency of the stops. The qualities of the organ when finished are said to have elicited the surprise and admiration of musicians.[71]

The leisure time which Watt did not occupy with miscellaneous work of this sort, he spent in reading. He did not want for books, as the College library was near at hand; and the professors as well as students were willing to lend him from their stores. He was not afraid of solid, heavy, dry books, provided he could learn something from them. All were alike welcome; and one of his greatest pleasures was in devouring a novel, when it fell in his way. He is even said to have occupied himself in writing tales and verses when he had nothing else to do. As none of his attempts have been preserved, we cannot offer an opinion upon them; but it is doubtful whether Watt’s poetry and fiction would display the same originality and power of invention as his steam-engine. The only youthful exercises of his which have been preserved are anything but poetical. One of them, at Heathfield, is a ‘Treatise on Practical Megethometry;’ and another is a ‘Compendium of Definitions,’ in Latin, by Gerard de Vries, both written in a neat round hand.

Like most of the Glasgow citizens of that time, Watt occasionally visited his club, where he cultivated the society of men of greater culture and experience than himself.[72] As he afterwards observed to a friend, “Our conversations then, besides the usual subjects with young men, turned principally on literary topics, religion, morality, belles-lettres, &c.; and to those conversations my mind owed its first bias towards such subjects, in which they were all much my superiors, I never having attended a college, and being then but a mechanic.”

There was another circumstance connected with his situation at this time which must have been peculiarly agreeable to a young man of his character, aspirations, and thirst for knowledge. His shop, being conveniently situated within the College, was a favourite resort of the professors and the students. They were attracted by the ingenious instruments and models which the shop contained, and the pleasure always felt in witnessing the proceedings of a skilful mechanic at his work, but more particularly by the easy, unaffected, and original conversation of Watt himself. Though a comparative youth, the professors were usually glad to consult him on points of mechanical knowledge and practice; and the acuteness of his observation, the accuracy of his knowledge, and the readiness with which he communicated what he knew, soon rendered him a general favourite. Among his most frequent visitors were Dr. Joseph Black, the distinguished professor of chemistry, who there contracted a friendship with Watt which lasted, uninterrupted, for a period of forty years, until the Doctor’s death; Professor Simson, one of the most eminent men of his day, whom Lord Brougham has described as the restorer of the science of geometry; Dr. Dick, the Professor of Natural Philosophy; and Professor Anderson.[73] Dr. Moor and Dr. Adam Smith were also frequent callers. But of all Watt’s associates, none is more closely connected with his name and history than John Robison, then a student at Glasgow College, and afterwards Professor of Natural Philosophy at Edinburgh.

Robison was nearer Watt’s age than the rest, and stood in the intimate relation to him of bosom friend, as well as fellow inquirer in science. He was handsome and prepossessing in appearance, frank and lively, full of fancy and humour, and a general favourite in the College. He was a capital talker, an accomplished linguist, and a good musician; yet, with all his versatility, he was a profound thinker and a diligent student, especially in mathematical and mechanical science, as he afterwards proved in his elaborate ‘System of Mechanical Philosophy,’ edited by Sir David Brewster, and his many able contributions to the ‘Encyclopædia Britannica,’ of which he was the designer and editor.

Robison’s introduction to Watt has been described by himself. After feasting his eyes on the beautifully-finished instruments in his shop, Robison entered into conversation with him. Expecting to find only a workman, he was surprised to discover a philosopher. “I had the vanity,” says Robison, “to think myself a pretty good proficient in my favourite study (mathematical and mechanical philosophy), and was rather mortified at finding Mr. Watt so much my superior. But his own high relish for these things made him pleased with the chat of any person who had the same tastes with himself; and his innate complaisance made him indulge my curiosity, and even encourage my endeavours to form a more intimate acquaintance with him. I lounged much about him, and, I doubt not, was frequently teasing him. Thus our acquaintance began.”

In Watt’s workshop also, Robison first met Dr. Black, and there initiated a friendship which ended only with death. “My first acquaintance with him,” Robison afterwards wrote Watt, “began in your rooms when you were rubbing up Macfarlane’s instruments. He used to come in, and, standing with his back to us, amuse himself with Bird’s quadrant, whistling softly to himself, in a manner that thrilled me to the heart.”

In 1757 Robison applied for the office of assistant to Dr. Dick, Professor of Natural Philosophy, in the place of the son of that gentleman, who had just died; but though he had already taken the degree of Master of Arts, he was thought too young to hold so important an office, being only about nineteen years old. His friends wished him to study for the church; but, preferring some occupation in which his mechanical tastes might be indulged, he turned his eyes to London. Furnished with letters from Professor Dick and Dr. Simson, he obtained an introduction to Admiral Knowles, who engaged him to take charge of his son’s instruction while at sea. In that capacity he sailed from Spithead in 1759, with the fleet which assisted the land forces in the taking of Quebec; he and his pupil being rated as midshipmen in the Admiral’s ship. Robison was on duty in the boat which carried Wolfe to the point where the army scaled the heights of Montcalm the night before the battle; and as the sun was setting in the west, the General, doubtless from an association of ideas suggested by the dangers of the coming struggle, recited, in an under tone, Gray’s ‘Elegy on a Country Churchyard;’ and when he had finished, said, “Now, gentlemen, I would rather have been the author of that poem than take Quebec.”

When Robison returned from his voyagings in 1763, a travelled man,—having had the advantage, during his absence, of acting as confidential assistant of Admiral Knowles in his marine surveys and observations,—he reckoned himself more than on a par with Watt; but he soon found that, during the period of his absence from Glasgow, his friend had been even busier than himself. When they entered into conversation, he found Watt continually striking into new paths where he was obliged to be his follower. The extent of the mathematical instrument maker’s investigations was no less remarkable than the depth to which he had pursued them. Not only had he mastered the principles of engineering, civil and military, but diverged into studies in antiquity, natural history, languages, criticism, and art. Every pursuit became science in his hands, and he made use of his subsidiary knowledge for the purpose of helping him towards his favourite objects.

Before long, Watt became to be regarded as one of the ablest men about college. “When to the superiority of knowledge in his own line,” said Robison, “which every man confessed, there was joined the naïve simplicity and candour of his character, it is no wonder that the attachment of his acquaintances was so strong. I have seen something of the world,” he continued, “and I am obliged to say that I never saw such another instance of general and cordial attachment to a person whom all acknowledged to be their superior. But this superiority was concealed under the most amiable candour, and liberal allowance of merit to every man. Mr. Watt was the first to ascribe to the ingenuity of a friend things which were very often nothing but his own surmises followed out and embodied by another. I am well entitled to say this, and have often experienced it in my own case.”

There are few traits in biography more charming than this generous recognition of merit mutually attributed by the one friend to the other. Arago, in quoting the words of Robison, has well observed that it is difficult to determine whether the honour of having thus recorded them be not as great as that of having inspired them.

CHAPTER VII.
Watt’s Experiments on Steam—Invents the Separate Condenser.

It was in the year 1759 that Robison 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 tinplate, 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 on Robison leaving 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 began 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, from 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.[74] 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 the cock and shutting off the connexion 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 instead of by the hand, and the whole be made to work by itself with perfect regularity. But there was an objection to this method. Water is converted into vapour 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 pursuing his experiments. Watt’s own account of his early experiments will be found appended as notes to Brewster’s edition of the articles ‘Steam and Steam-engines,’ written by Dr. Robison for the ‘Encyclopædia Britannica,’ and afterwards published in a separate form.

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 tea-kettle. 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 endeavoured 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, when 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 which was performed by 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 the 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 begun 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.”[75]

When Watt found that water, in its conversion into vapour, became such a reservoir of heat, he was more than ever bent on economising 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 endeavoured, 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 vapour 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.

We revert for a moment to the progress of Watt’s instrument-making business. The shop in the College was not found to answer, being too far from the principal thoroughfares. If he wanted business he must go nearer to the public, for it was evident that they would not come to him. But to remove to a larger shop, in a more central quarter, involved an expenditure of capital for which he was himself unequal. His father had helped him with money as long as he could, but could do so no longer. Though he was as much respected by his neighbours as ever, he had grown poor by his losses; and, instead of giving help, himself needed it. Watt therefore looked about him for a partner with means, and succeeded in finding one in a Mr. John Craig, in conjunction with whom he opened a retail shop in the Salt-market, nearly opposite St. Andrew’s Street, about the year 1760; removing from thence to Buchanan’s Land, on the north side of the Trongate, a few years later.[76] Watt’s partner was not a mechanic, but he supplied the requisite capital, and attended to the books. The partnership was on the whole successful, as we infer from the increased number of hands employed. At first Watt could execute all his orders himself, and afterwards by the help of a man and a boy; but by the end of 1764, the number of hands employed by the firm had increased to sixteen.

His improving business brought with it an improving income, and Watt—always a frugal and thrifty man—began to save a little money. He was encouraged to economise by another circumstance—his intended marriage with his cousin, Margaret Miller. In anticipation of this event, he had removed from his rooms in the College to a house in Delftfield Lane—a narrow passage then parallel with York Street, but now converted into the spacious thoroughfare of Watt Street. Having furnished his house in a plain yet comfortable style, he brought home his young wife, and installed her there in July, 1764. The step was one of much importance to his personal wellbeing. Mrs. Watt was of a lively, cheerful temperament; and as Watt himself was of a meditative disposition, prone to melancholy, and a frequent sufferer from nervous headache, her presence at his fireside could not fail to have a beneficial influence upon his health and comfort.