James Watt

His blood was up. No dealings with rascals!

July, 1781, Watt had finished his studies, went to Penryn, and swore he had "invented certain new methods of applying the vibrating or reciprocating motion of steam or fire engines to produce a continued rotation or circular motion round an axis or centre, and thereby to give motion to the wheels of mills or other machines."

Watt proceeded to work out the plan of the rotary engine, stimulated by numerous inquiries for steam engines for driving all kinds of mills. He found that "the people in London, Manchester and Birmingham are steam-mill mad."

During many long years of trial with their financial troubles, inferior and drunken workmen, disappointing engines, Cornish mine-owners to annoy him, it is highly probable that Watt only found relief in retiring to his garret to gratify his passion for solving difficult mechanical problems. We may even imagine that from his serious mission—the development of the engine—which was ever present, he sometimes flew to the numerous less exhausting inventions for recreation, as the weary student flies to fiction. His mind at this period seems never to have been at rest. His voluminous correspondence constantly reveals one invention after another upon which he was engaged. A new micrometer, a dividing screw, a new surveying-quadrant, problems for clearing the observed distance of the moon from a star of the effects of refraction and parallax, a drawing-machine, a copying-machine for sculpture—anything and everything he used or saw seems immediately to have been subjected to the question: "Cannot this be improved?" usually with a response in the affirmative.

As we have read, he had long studied the question of a locomotive steam carriage. In Muirhead's Biography, several pages are devoted to this. In his seventh "new improvement," in his patent of 1784, he describes "the principle and construction of steam engines which are applied to give motion to wheel carriages for removing persons, goods, or other matter from place to place, in which case the engines themselves must be portable." Mr. Murdoch made a model of the engine here specified which performed well, but nothing important came of all this until 1802, when the problem was instantly changed by Watt's friend, Mr. Edgeworth, writing him, "I have always thought that steam would become the universal lord, and that we should in time scorn post-horses. An iron railroad would be a cheaper thing than a road of the common construction." Here lay in a few words the idea from which our railway system has sprung. Surely Edgeworth deserves to be placed among the immortals.[3] As in the case of the steamship, however, the indispensable steam engine of Watt had to furnish the motive power. The railroad is only the necessary smooth track upon which the steam engine could perform its miracle. It is significant that steam power upon roads required the abandonment of the usual highway. So we may believe is the automobile to force new roads of its own, or to widen existing highways, rendering those safe under certain rules for speed of twenty miles per hour, or even more, when they were intended only for eight or ten.

The reading lamp of Watt's day was a poor affair, and as he never saw an inefficient instrument without studying its improvement, he produced a new lamp. He wrote Argand of the Argand burner upon the subject and for a long time Watt lamps were made at the Soho works, which gave a light surpassing in steadiness and brilliance anything of the kind that had yet appeared. He gives four plans for lamps, "with the reservoir below and the stem as tall as you please." He also made an instrument for determining the specific gravity of liquids, and a year after this he "found out a method of working tubes of the elastic resin without dissolving it." The importance of such tubes for a thousand purposes in the arts and sciences is now appreciated.

Watt gave much time to an arithmetical machine which he found exceedingly simple to plan, but he adds, "I have learnt by experience that in mechanics many things fall out between the cup and the mouth." He describes what it is to accomplish, but it remained for Babbage at a much later date to perfect the machine. A machine for copying sculpture amused him for a time but it was never finished.

If any difficulty of a mechanical nature arose, people naturally turned to Watt for a solution. Thus the Glasgow University failed to get pipes for conveying water across the Clyde to stand, the channel of the river being covered with mud and shifty sand, full of inequalities, and subject to the pressure of a considerable body of water. Application was at last made to the recognised genius. If he could not solve it, who could? This was just one of the things that Watt liked to do. He promptly devised an articulated suction pipe with parts formed on the principle of a lobster's tail. This crustacean tube a thousand feet long solved the matter. Watt stated that his services were induced solely by a desire to be of use in procuring good water to the city of Glasgow, and to promote the prosperity of a company which had risked so much for the public good. These were handsomely acknowledged by the presentation to him of a valuable piece of plate.

As another proof of Watt's habit of thinking of everything that could possibly be improved, it may be news to many readers that the consumption of the smoke from steam engines early attracted his attention, and that he patented devices for this. These have been substantially followed in the numerous attempts which have been made from time to time to reduce the huge volumes of smoke that keep so many cities under a cloud. He was successful and his son James writes to him in 1790 from Manchester:

It is astonishing what an impression the smoke-consuming power of the engine has made upon everybody hereabouts. They scarcely trusted to the evidence of their senses. You would be diverted to hear the strange hypotheses which have been stated to account for it.

This is all very well. It is certain that most of the smoke made in manufacturing concerns can be consumed, if manufacturers are compelled by law to erect sufficient heating surface and to include the well-known appliances, including those for careful firing, but no city so far as the writer knows has ever been able to enforce effective laws. There remain the dwellings of the people to deal with, which give forth smoke in large cities in the aggregate far exceeding that made by the manufacturing plants. New York pursues the only plan for ensuring the clearest skies of any large city in the world where coal is generally used, by making the use of bituminous coal unlawful. The enormous growth of present New York (45 per cent. in last decade) is not a little dependent upon the attraction of clear blue sides and the resulting cleanliness of all things in and about the city compared with others. When, by the progress of invention or new methods of distributing heat, smoke is banished, as it probably will be some day, many rich citizens will remain in their respective western cities instead of flocking to the clear blue-skied metropolis, as they are now so generally doing.

Such were some of Watt's by-products. His recreation, if found at all, was found in change of occupation. We read of no idle days, no pleasure trips, no vacations, only change of work.

Rumors of new inventions of engines far excelling his continued to disturb Watt, and much of his time was given to investigation. He thought of a caloric air engine as possibly one of the new ideas; then of the practicability of producing mechanical power by the absorption and condensation of gas on the one hand and by its disengagement and expansion on the other. His mind seemed to range over the entire field of possibilities.

The Hornblower engine had been heralded as sure to displace the Watt. When it was described, it proved to be as Watt said, "no less than our double-cylinder engine, worked upon our principle of expansion. It is fourteen years since I mentioned it to Mr. Smeaton." Watt had explained to Dr. Small his method of working steam expansively as early as May, 1769, and had adopted it in the Soho engine and also in the Shadwell engine erected in that year.

We have seen before that Watt had to retrace his steps and abandon for a time in later engines what he had before ventured upon.

The application of steam for propelling boats upon the water was, at this time (1788), attracting much attention. Boulton and Watt were urged to undertake experiments. This they declined to entertain, having their facilities fully employed in their own field, but finally Fulton, on August 6, 1803, ordered an engine from them from his own drawings, intended for this purpose, repeating the order in person in 1804. It was shipped to America early in 1805, and in 1807 placed upon the Clermont, which ran upon the Hudson River as a passenger boat, attaining a speed of about five miles an hour. This was the first steamboat that was ever used for passengers, and altho Fulton neither invented the boat nor the engine, nor the combination of the two, still he is entitled to great credit for overcoming innumerable difficulties sufficient to discourage most men. Fulton, who was the son of a Scotsman from Dumfrieshire, visited Syminton's steamboat, the Charlotte Dundas, in Scotland, in 1801, and had seen it successfully towing canal boats upon the Forth and Clyde Canal. This was the first boat ever propelled by steam successfully for commercial purposes. It was subsequently discarded, not because it did not tow the canal boats, but because the revolving paddle-wheels caused waves that threatened to wash away the canal banks.

Several engines were sent to New York. The men in charge of one found on shipboard a pattern-maker going to America named John Hewitt. He settled in America January 12th, 1796, and became the father of the late famous and deeply lamented Hon. Abram S. Hewitt, long a member of Congress and afterward mayor of New York, foremost in many improvements in the city, the last being the Subway, just opened, which owes its inception to him. For this service, the Chamber of Commerce presented him with a memorial medal. Mr. Hewitt married a daughter of Peter Cooper, founder of the Cooper Institute, which owes its wonderful development chiefly to him. His children devote themselves and their fortunes to its management. At the time of his death in 1902, he was pronounced "the first private citizen of the Republic." Small engine-shops (of which the ruins still remain), called "Soho" after their prototype, were erected by his father near New York city, on the Greenwood division of the Erie Railroad. The railroad station was called "Soho" by Mr. Abram S. Hewitt, who was then president of the railroad company. Upon Mr. Hewitt's eightieth birthday congratulations poured in from all quarters. One cable from abroad attracted attention as appropriate and deserved: "Ten octaves every note truly struck and grandly sung." No man in private life passed away in our day with such general lamentation. The Republic got even more valuable material than engines from the old home in the ship that arrived on January 12, 1796.

We must not permit ourselves to forget that it was not until the Watt engine was applied to steam navigation that the success of the latter became possible. It was only by this that it could be made practicable, so that the steamship is the product of the steam-engine, and it is to Watt we owe the modern twenty-three-thousand-ton monster (and larger monsters soon to come), which keeps its course against wind and tide, almost "unshaked of motion," for this can now properly be said. Passengers crossing the Atlantic from port to port now scarcely know anything of irregular motion, and never more than the gentlest of slight heaves, even during the gale that

The ocean, traversed in these ships, is a smooth highway—nothing but a ferry—and a week spent upon it has become perhaps the most enjoyable and the most healthful of holiday excursions, provided the prudent excursionist has left behind positive instructions that wireless telegrams shall not follow.

CHAPTER VII

A detailed specification for a road steam-carriage concludes the claims of this patent, but the idea of railroads, instead of common roads, coming later left the construction of the locomotive to Stephenson.[1]

Watt's last patent bears date June 14, 1785, and was

for certain newly improved methods of constructing furnaces or fire-places for heating, boiling, or evaporating of water and other liquids which are applicable to steam engines and other purposes, and also for heating, melting, and smelting of metals and their ores, whereby greater effects are produced from the fuel, and the smoke is in a great measure prevented or consumed.

The principle, "an old one of my own," as Watt says, is in great part acted upon to-day.

So numerous were the improvements made by Watt at various periods, which greatly increased the utility of his engine, it would be in vain to attempt a detailed recital of his endless contrivances, but we may mention as highly important, the throttle-valve, the governor, the steam-gauge and the indicator. Muirhead says:

The throttle-valve is worked directly by the engineer to start or stop the engine, and also to regulate the supply of steam. Watt describes it as a circular plate of metal, having a spindle fixed across its diameter, the plate being accurately fitted to an aperture in a metal ring of some thickness, through the edgeway of which the spindle is fitted steam-tight, and the ring fixed between the two flanches of the joint of the steam-pipe which is next to the cylinder. One end of the spindle, which has a square upon it, comes through the ring, and has a spanner fixed upon it, by which it can be turned in either direction. When the valve is parallel to the outsides of the ring, it shuts the opening nearly perfectly; but when its plane lies at an angle to the ring, it admits more or less steam according to the degree it has opened; consequently the piston is acted upon with more or less force.

Papin preferred gunpowder as a safer source of power than steam, but that was before it had been automatically regulated by the "Governor." The governor has always been the writer's favorite invention, probably because it was the first he fully understood. It is an application of the centrifugal principle adapted and mechanically improved. Two heavy revolving balls swing round an upright rod. The faster the rod revolves the farther from it the balls swing out. The slower it turns the closer the balls fall toward it. By proper attachments the valve openings admitting steam are widened or narrowed accordingly. Thus the higher speed of the engine, the less steam admitted, the slower the speed the more steam admitted. Hence any uniform speed desired can be maintained: should the engine be called upon to perform greater service at one moment than another, as in the case of steel rolling mills, speed being checked when the piece of steel enters the rolls, immediately the valves widen, more steam rushes into the engine, and vice versa. Until the governor came regular motion was impossible—steam was an unruly steed.

Arago describes the steam-gauge thus:

It is a short glass tube with its lower end immersed in a cistern of mercury, which is placed within an iron box screwed to the boiler steam-pipe, or to some other part communicating freely with the steam, which, pressing on the surface of the mercury in the cistern, raises the mercury in the tube (which is open to the air at the upper end), and its altitude serves to show the elastic power of the steam over that of the atmosphere.

The indicator he thus describes:

The barometer being adapted only to ascertain the degree of exhaustion in the condenser where its variations were small, the vibrations of the mercury rendered it very difficult, if not impracticable, to ascertain the state of the exhaustion of the cylinder at the different periods of the stroke of the engine; it became therefore necessary to contrive an instrument for that purpose that should be less subject to vibration, and should show nearly the degree of exhaustion in the cylinder at all periods. The following instrument, called the Indicator, is found to answer the end sufficiently. A cylinder about an inch diameter, and six inches long, exceedingly truly bored, has a solid piston accurately fitted to it, so as to slide easy by the help of some oil; the stem of the piston is guided in the direction of the axis of the cylinder, so that it may not be subject to jam, or cause friction in any part of its motion. The bottom of this cylinder has a cock and small pipe joined to it which, having a conical end, may be inserted in a hole drilled in the cylinder of the engine near one of the ends, so that, by opening the small cock, a communication may be effected between the inside of the cylinder and the indicator.

The cylinder of the indicator is fastened upon a wooden or metal frame, more than twice its own length; one end of a spiral steel spring, like that of a spring steel-yard, is attached to the upper part of the frame, and the other end of the spring is attached to the upper end of the piston-rod of the indicator. The spring is made of such a strength, that when the cylinder of the indicator is perfectly exhausted, the pressure of the atmosphere may force its piston down within an inch of its bottom. An index being fixed to the top of its piston-rod, the point where it stands, when quite exhausted, is marked from an observation of a barometer communicating with the same exhausted vessel, and the scale divided accordingly.

Improvements come in many ways, sometimes after much thought and after many experimental failures. Sometimes they flash upon clever inventors, but let us remember this is only after they have spent long years studying the problem. In the case of the steam engine, however, a quite important improvement came very curiously. Humphrey Potter was a lad employed to turn off and on the stop cocks of a Newcomen engine, a monotonous task, for, at every stroke one had to be turned to let steam into the boiler and another for injecting the cold water to condense it, and this had to be done at the right instant or the engine could not move. How to relieve himself from the drudgery became the question. He wished time to play with the other boys whose merriment was often heard at no great distance, and this set him thinking. Humphrey saw that the beam in its movements might serve to open and shut these stop cocks and he promptly began to attach cords to the cocks and then tied them at the proper points to the beam, so that ascending it pulled one cord and descending the other. Thus came to us perhaps not the first automatic device, but no doubt the first of its kind that was ever seen there. The steam engine henceforth was self-attending, providing itself for its own supply of steam and for its condensation with perfect regularity. It had become in this feature automatic.

The cords of Potter gave place to vertical rods with small pegs which pressed upward or downward as desired. These have long since been replaced by other devices, but all are only simple modifications of a contrivance devised by the mere lad whose duty it was to turn the stop cocks.

It would be interesting to know the kind of man this precocious boy inventor became, or whether he received suitable reward for his important improvement. We search in vain; no mention of him is to be found. Let us, however, do our best to repair the neglect and record that, in the history of the steam engine, Humphrey Potter must ever be honorably associated with famous men as the only famous boy inventor.

In the development of the steam engine, we have one purely accidental discovery. In the early Newcomen engines, the head of the piston was covered by a sheet of water to fill the spaces between the circular contour of the movable piston and the internal surface of the cylinder, for there were no cylinder-boring tools in those days, and surfaces of cylinders were most irregular. To the surprise of the engineer, the engine began one day working at greatly increased speed, when it was found that the piston-head had been pierced by accident and that the cold water had passed in small drops into the cylinder and had condensed the steam, thus rapidly making a more perfect vacuum. From this accidental discovery came the improved plan of injecting a shower of cold water through the cylinder, the strokes of the engine being thus greatly increased.

The year 1783 was one of Watt's most fruitful years of the dozen which may be said to have teemed with his inventions. His celebrated discovery of the composition of water was published in this year. The attempts made to deprive him of the honor of making this discovery ended in complete failure. Sir Humphrey Davy, Henry, Arago, Liebig, and many others of the highest authority acknowledged and established Watt's claims.

The true greatness of the modest Watt was never more finely revealed than in his correspondence and papers published during the controversy. Watt wrote Dr. Black, April 21st, that he had handed his paper to Dr. Priestley to be read at the Royal Society. It contained the new idea of water, hitherto considered an element and now discovered to be a compound. Thus was announced one of the most wonderful discoveries found in the history of science. It was justly termed the beginning of a new era, the dawn of a new day in physical chemistry, indeed the real foundation for the new system of chemistry, and, according to Dr. Young, "a discovery perhaps of greater importance than any single fact which human ingenuity has ascertained either before or since." What Newton had done for light Watt was held to have done for water. Muirfield well says:

It is interesting in a high degree to remark that for him who had so fully subdued to the use of man the gigantic power of steam it was also reserved to unfold its compound natural and elemental principles, as if on this subject there were to be nothing which his researches did not touch, nothing which they touched that they did not adorn.

Arago says:

In his memoir of the month of April, Priestley added an important circumstance to those resulting from the experiments of his predecessors: he proved that the weight of the water which is deposited upon the sides of the vessel, at the instant of the detonation of the oxygen and hydrogen, is precisely the same as the weights of the two gases.

Watt, to whom Priestley communicated this important result, immediately perceived that proof was here afforded that water was not a simple body. Writing to his illustrious friend, he asks:

What are the products of your experiment? They are water, light and heat. Are we not, thence, authorised to conclude that water is a compound of the two gases, oxygen and hydrogen, deprived of a portion of their latent or elementary heat; that oxygen is water deprived of its hydrogen, but still united to its latent heat and light? If light be only a modification of heat, or a simple circumstance of its manifestation, or a component part of hydrogen, oxygen gas will be water deprived of its hydrogen, but combined with latent heat.

This passage, so clear, so precise, and logical, is taken from a letter of Watt's, dated April 26, 1783. The letter was communicated by Priestley to several of the scientific men in London, and was transmitted immediately afterward to Sir Joseph Banks, the President of the Royal Society, to be read at one of the meetings of that learned body.

Watt had for many years entertained the opinion that air was a modification of water. He writes Boulton, December 10, 1782:

You may remember that I have often said, that if water could be heated red-hot or something more, it would probably be converted into some kind of air, because steam would in that case have lost all its latent heat, and that it would have been turned solely into sensible heat, and probably a total change of the nature of the fluid would ensue.

A month after he hears of Priestley's experiments, he writes Dr. Black (April 21, 1783) that he "believes he has found out the cause of the conversion of water into air." A few days later, he writes to Dr. Priestley:

In the deflagration of the inflammable and dephlogisticated airs, the airs unite with violence—become red-hot—and, on cooling, totally disappear. The only fixed matter which remains is water; and water, light, and heat, are all the products. Are we not then authorised to conclude that water is composed of dephlogisticated and inflammable air, or phlogiston, deprived of part of their latent heat; and that dephlogisticated, or pure air, is composed of water deprived of its phlogiston, and united to heat and light; and if light be only a modification of heat, or a component part of phlogiston, then pure air consists of water deprived of its phlogiston and of latent heat?

It appears from the letter to Dr. Black of April 21st, that Mr. Watt had, on that day, written his letter to Dr. Priestley, to be read by him to the Royal Society, but on the 26th he informs Mr. DeLuc, that having observed some inaccuracies of style in that letter, he had removed them, and would send the Doctor a corrected copy in a day or two, which he accordingly did on the 28th; the corrected letter (the same that was afterward embodied verbatim in the letter to Mr. DeLuc, printed in the Philosophical Transactions), being dated April 26th. In enclosing it, Mr. Watt adds, "As to myself, the more I consider what I have said, I am the more satisfied with it, as I find none of the facts repugnant."

Thus was announced for the first time one of the most wonderful discoveries recorded in the history of science, startling in its novelty and yet so simple.

Watt had divined the import of Priestley's experiment, for he had mastered all knowledge bearing upon the question, but even when this was communicated to Priestley, he could not accept it, and, after making new experiments, he writes Watt, April 29, 1783, "Behold with surprise and indignation the figure of an apparatus that has utterly ruined your beautiful hypothesis," giving a rough sketch with his pen of the apparatus employed. Mark the promptitude of the master who had deciphered the message which the experimenter himself could not translate. He immediately writes in reply May 2, 1783:

I deny that your experiment ruins my hypothesis. It is not founded on so brittle a basis as an earthen retort, nor on its converting water into air. I founded it on the other facts, and was obliged to stretch it a good deal before it would fit this experiment.... I maintain my hypothesis until it shall be shown that the water formed after the explosion of the pure and inflammable airs, has some other origin.

He also writes to Mr. DeLuc on May 18th:

I do not see Dr. Priestley's experiment in the same light that he does. It does not disprove my theory.... My assertion was simply, that air (i.e., dephlogisticated air, or oxygen, which was also commonly called vital air, pure air, or simple air) was water deprived of its phlogiston, and united to heat, which I grounded on the decomposition of air by inflammation with inflammable air, the residuum, or product of which, is only water and heat.

Having, by experiments of his own, fully satisfied himself of the correctness of his theory, in November he prepared a full statement for the Royal Society, having asked the society to withhold his first paper until he could prove it for himself by experiment. He never doubted its correctness, but some members of the society advised that it had better be supported by facts.

When the discovery was so daring that Priestley, who made the experiments, could not believe it and had to be convinced by Watt of its correctness, there seems little room left for other claimants, nor for doubt as to whom is due the credit of the revelation.

Watt encountered the difficulties of different weights and measures in his studies of foreign writers upon chemistry, a serious inconvenience which still remains with us.

He wrote Mr. Kirwan, November, 1783:

I had a great deal of trouble in reducing the weights and measures to speak the same language; and many of the German experiments become still more difficult from their using different weights and different divisions of them in different parts of that empire. It is therefore a very desirable thing to have these difficulties removed, and to get all philosophers to use pounds divided in the same manner, and I flatter myself that may be accomplished if you, Dr. Priestley, and a few of the French experimenters will agree to it; for the utility is so evident, that every thinking person must immediately be convinced of it.

Here follows his plan: Let the

Philosophical pound consist of 10 ounces, or 10,000 grains.
the ounce    "    "  10 drachms or 1,000    "
the drachm  "    "  100 grains.

Let all elastic fluids be measured by the ounce measure of water, by which the valuation of different cubic inches will be avoided, and the common decimal tables of specific gravities will immediately give the weights of those elastic fluids.

If all philosophers cannot agree on one pound or one grain, let every one take his own pound or his own grain; it will affect nothing but doses of medicines, which must be corrected as is now done; but as it would be much better that the identical pound was used by all. I would propose that the Amsterdam or Paris pound be assumed as the standard, being now the most universal in Europe: it is to our avoirdupois pound as 109 is to 100. Our avoirdupois pound contains 7,000 of our grains, and the Paris pound 7,630 of our grains, but it contains 9,376 Paris grains, so that the division into 10,000 would very little affect the Paris grain. I prefer dividing the pound afresh to beginning with the Paris grain, because I believe the pound is very general, but the grain local.

Dr. Priestley has agreed to this proposal, and has referred it to you to fix upon the pound if you otherwise approve of it. I shall be happy to have your opinion of it as soon as convenient, and to concert with you the means of making it universal.... I have some hopes that the foot may be fixed by the pendulum and a measure of water, and a pound derived from that; but in the interim let us at least assume a proper division, which from the nature of it must be intelligible as long as decimal arithmetic is used.

He afterward wrote, in a letter to Magellan:

As to the precise foot or pound, I do not look upon it to be very material, in chemistry at least. Either the common English foot may be adopted according to your proposal, which has the advantage that a cubic foot is exactly 1,000 ounces, consequently the present foot and ounce would be retained; or a pendulum which vibrates 100 times a minute may be adopted for the standard, which would make the foot 14.2 of our present inches, and the cubic foot would be very exactly a bushel, and would weigh 101 of the present pounds, so that the present pound would not be much altered. But I think that by this scheme the foot would be too large, and that the inconvenience of changing all the foot measures and things depending on them, would be much greater than changing all the pounds, bushels, gallons, etc. I therefore give the preference to those plans which retain the foot and ounce.

The war of the standards still rages—metric, or decimal, or no change. What each nation has is good enough for it in the opinion of many of its people. Some day an international commission will doubtless assemble to bring order out of chaos. As far as the English-speaking race is concerned, it seems that a decided improvement could readily be affected with very trifling, indeed scarcely perceptible, changes. Especially is this so with money values. Britain could merge her system with those of Canada and America, by simply making her "pound" the exact value of the American five dollars, it being now only ten pence less; her silver coinage one and two shillings equal to quarter- and half-dollars, the present coin to be recoined upon presentation, but meanwhile to pass current. Weights and measures are more difficult to assimilate. Science being world-wide, and knowing no divisions, should use uniform terms. Alas! at the distance of nearly a century and a half we seem no nearer the prospect of a system of universal weights and measures than in Watt's day, but Watt's idea is not to be lost sight of for all that. He was a seer who often saw what was to come.

We have referred to the absence of holidays in Watt's strenuous life, but Birmingham was remarkable for a number of choice spirits who formed the celebrated Lunar Society, whose members were all devoted to the pursuit of knowledge and mutually agreeable to one another. Besides Watt and Boulton, there were Dr. Priestley, discoverer of oxygen gas, Dr. Darwin, Dr. Withering, Mr. Keir, Mr. Galton, Mr. Wedgwood of Wedgwood ware fame, who had monthly dinners at their respective houses—hence the "Lunar" Society. Dr. Priestley, discoverer of oxygen, who arrived in Birmingham in 1780, has repeatedly mentioned the great pleasure he had in having Watt for a neighbor. He says:

I consider my settlement at Birmingham as the happiest event in my life; being highly favourable to every object I had in view, philosophical or theological. In the former respect I had the convenience of good workmen of every kind, and the society of persons eminent for their knowledge of chemistry; particularly Mr. Watt, Mr. Keir, and Dr. Withering. These, with Mr. Boulton and Dr. Darwin, who soon left us by removing from Lichfield to Derby, Mr. Galton, and afterwards Mr. Johnson of Kenilworth and myself, dined together every month, calling ourselves the Lunar Society, because the time of our meeting was near the full-moon—in order,

as he elsewhere says,

to have the benefit of its light in returning home.

Richard Lovell Edgeworth says of this distinguished coterie:

By means of Mr. Keir, I became acquainted with Dr. Small of Birmingham, a man esteemed by all who knew him, and by all who were admitted to his friendship beloved with no common enthusiasm. Dr. Small formed a link which combined Mr. Boulton, Mr. Watt, Dr. Darwin, Mr. Wedgwood, Mr. Day, and myself together—men of very different characters, but all devoted to literature and science. This mutual intimacy has never been broken but by death, nor have any of the number failed to distinguish themselves in science or literature. Some may think that I ought with due modesty to except myself. Mr. Keir, with his knowledge of the world and good sense; Dr. Small, with his benevolence and profound sagacity; Wedgwood, with his increasing industry, experimental variety, and calm investigation; Boulton, with his mobility, quick perception, and bold adventure; Watt, with his strong inventive faculty, undeviating steadiness, and bold resources; Darwin, with his imagination, science, and poetical excellence; and Day with his unwearied research after truth, his integrity and eloquence proved altogether such a society as few men have had the good fortune to live with; such an assemblage of friends, as fewer still have had the happiness to possess, and keep through life.

The society continued to exist until the beginning of the century, 1800. Watt was the last surviving member. The last reference is Dr. Priestley's dedication to it, in 1793, of one of his works "Experiments on the Generation of Air from Water," in which he says:

There are few things that I more regret, in consequence of my removal from Birmingham, than the loss of your society. It both encouraged and enlightened me; so that what I did there of a philosophical kind ought in justice to be attributed almost as much to you as to myself. From our cheerful meetings I never absented myself voluntarily, and from my pleasing recollection they will never be absent. Should the cause of our separation make it necessary for to me remove to a still greater distance from you, I shall only think the more, and with the more regret, of our past interviews.... Philosophy engrossed us wholly. Politicians may think there are no objects of any consequence besides those which immediately interest them. But objects far superior to any of which they have an idea engaged our attention, and the discussion of them was accompanied with a satisfaction to which they are strangers. Happy would it be for the world if their pursuits were as tranquil, and their projects as innocent, and as friendly to the best interests of mankind, as ours.

That the partners, Boulton and Watt, had such pleasure amid their lives of daily cares, all will be glad to know. It was not all humdrum money-making nor intense inventing. There was the society of gifted minds, the serene atmosphere of friendship in the high realms of mutual regard, best recreation of all.