Watt continued to pursue his studies as before. Though still occupied with his inquiries and experiments as to steam, he 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 other 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 expedient after another, finding out what would do by 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 favourite 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.

One Sunday afternoon, in the spring of 1765, he went to take an afternoon walk on the Green, then a quiet, grassy meadow, used as a bleaching and grazing-ground. On week-days the Glasgow lasses came thither with their largest kail-pots, to boil their clothes in; and sturdy queans might be seen, with coats kilted, tramping blankets in their tubs. On Sundays the place was comparatively deserted, and hence Watt, who lived close at hand, went there to take a quiet afternoon stroll. His thoughts were as usual running on the subject of his unsatisfactory experiments with the Newcomen engine, when the first idea of the separate condenser suddenly flashed upon his mind. But the notable discovery is best told in his own words, as related to Mr. Robert Hart, many years after:—

“I had gone to take a walk on a fine Sabbath afternoon. I had entered the Green by the gate at the foot of Charlotte Street, and had passed the old washing-house. I was thinking upon the engine at the time, and had gone as far as the herd’s house, when the idea came into my mind that as steam was an elastic body it would rush into a vacuum, and if a communication were made between the cylinder and an exhausted vessel, it would rush into it, and might be there condensed without cooling the cylinder. I then saw that I must get rid of the condensed steam and injection-water if I used a jet, as in Newcomen’s engine. Two ways of doing this occurred to me. First, the water might be run off by a descending pipe, if an off-let could be got at the depth of 35 or 36 feet, and any air might be extracted by a small pump. The second was to make the pump large enough to extract both water and air. He continued: I had not walked further than the Golf-house[77] when the whole thing was arranged in my mind.”[78]

Great and prolific ideas are almost always simple. What seems impossible at the outset appears so obvious when it is effected that we are prone to marvel that it did not force itself at once upon the mind. Late in life Watt, with his accustomed modesty, declared his belief that if he had excelled, it had been “by chance and the neglect of others.” To Professor Jardine he said “that when it was analysed the invention would not appear so great as it seemed to be. In the state,” said he, “in which I found the steam-engine, it was no great effort of mind to observe that the quantity of fuel necessary to make it work would for ever prevent its extensive utility. The next step in my progress was equally easy—to inquire what was the cause of the great consumption of fuel: this, too, was readily suggested, viz., the waste of fuel which was necessary to bring the whole cylinder, piston, and adjacent parts from the coldness of water to the heat of steam, no fewer than from fifteen to twenty times in a minute.” The question then occurred, how was this to be avoided or remedied? It was at this stage that the idea of carrying on the condensation in a separate vessel flashed upon his mind, and solved the difficulty.[79]

Mankind has been more just to Watt than he was to himself. There was no accident in the discovery. It had been the result of close and continuous study; and the idea of the separate condenser was merely the last step of a long journey—a step which could not have been taken unless the road which led to it had been traversed. Dr. Black says, “This capital improvement flashed upon his mind at once, and filled him with rapture;” a statement which, spite of the unimpassioned nature of Watt, we can readily believe.

On the morning following his Sunday afternoon’s walk on Glasgow Green, Watt was up betimes making arrangements for a speedy trial of his new plan. He borrowed from a college friend a large brass syringe, an inch and a third in diameter, and ten inches long, of the kind used by anatomists for injecting arteries with wax previous to dissection. The body of the syringe served for a cylinder, the piston-rod passing through a collar of leather in its cover. A pipe connected with the boiler was inserted at both ends for the admission of steam, and at the upper end was another pipe to convey the steam to the condenser. The axis of the stem of the piston was drilled with a hole, fitted with a valve at its lower end, to permit the water produced by the condensed steam on first filling the cylinder to escape. The first condenser made use of was an improvised cistern of tinned plate, provided with a pump to get rid of the water formed by the condensation of the steam, both the condensing-pipes and the air-pump being placed in a reservoir of cold water.

But, although the invention was complete in Watt’s mind, it took him many long and laborious years to work out the details of the engine. His friend Robison, with whom his intimacy was maintained during these interesting experiments, has given a graphic account of the difficulties which he successively encountered and overcame. He relates that on his return from the country, after the College vacation in 1765, he went to have a chat with Watt and communicate to him some observations he had made on Desaguliers’ and Belidor’s account of the steam-engine. He went straight into the parlour, without ceremony, and found Watt sitting before the fire looking at a little tin cistern which he had on his knee. Robison immediately started the conversation about steam, his mind, like Watt’s, being occupied with the means of avoiding the excessive waste of heat in the Newcomen engine. Watt, all the while, kept looking into the fire, and after a time laid down the cistern at the foot of his chair, saying nothing. It seems that Watt felt rather nettled at Robison having communicated to a mechanic of the town a contrivance which he had hit upon for turning the cocks of his engine. When Robison therefore pressed his inquiry, Watt at length looked at him and said briskly, “You need not fash yourself any more about that, man; I have now made an engine that shall not waste a particle of steam. It shall all be boiling hot,—ay, and hot water injected, if I please.” He then pushed the little tin cistern with his foot under the table.

Robison could learn no more of the new contrivance from Watt at that time; but on the same evening he accidentally met a mutual acquaintance, who, supposing he knew as usual the progress of Watt’s experiments, observed to him, “Well, have you seen Jamie Watt?” “Yes.” “He’ll be in fine spirits now with his engine?” “Yes,” said Robison, “very fine spirits.” “Gad!” said the other, “the separate condenser’s the thing: keep it but cold enough, and you may have a perfect vacuum, whatever be the heat of the cylinder.” This was Watt’s secret, and the nature of the contrivance was clear to Robison at once.

It will be observed that Watt had not made a secret of it to his other friends. Indeed Robison himself admitted that one of Watt’s greatest delights was to communicate the results of his experiments to others, and set them upon the same road to knowledge with himself; and that no one could display less of the small jealousy of the tradesman than he did. To his intimate friend, Dr. Black, he communicated the progress made by him at every stage; and the Doctor kindly encouraged him in his struggles, cheered him in his encounter with difficulty, and, what was of still more practical value at the time, he helped him with money to enable him to prosecute his invention. Communicative though Watt was disposed to be, he learnt reticence when he found himself exposed to the depredations of the smaller fry of inventors. Robison says that had he lived in Birmingham or London at the time, the probability is that some one or other of the numerous harpies who live by sucking other people’s brains, would have secured patents for his more important inventions, and thereby deprived him of the benefits of his skill, science, and labour. As yet, however, there were but few mechanics in Glasgow capable of understanding or appreciating the steam-engine; and the intimate friends to whom he freely spoke of his discovery were too honourable-minded to take advantage of his confidence. Shortly after, Watt fully communicated to Robison the different stages of his invention, and the results at which he had arrived, much to the delight of his friend.

It will be remembered that in the Newcomen engine the steam was only employed for the purpose of producing a vacuum, and that its working power was in the down stroke, which was effected by the pressure of the air upon the piston; hence it is now usual to call it the atmospheric engine. Watt perceived that the air which followed the piston down the cylinder would cool the latter, and that steam would be wasted in re-heating it. In order, therefore, to avoid this loss of heat, he resolved to put an air-tight cover upon the cylinder, with a hole and stuffing-box for the piston-rod to slide through, and to admit steam above the piston, to act upon it instead of the atmosphere. When the steam had done its duty in driving down the piston, a communication was opened between the upper and lower part of the cylinder, and the same steam, distributing itself equally in both compartments, sufficed to restore equilibrium. The piston was now drawn up by the weight of the pump-gear; the steam beneath it was then condensed in the separate vessel so as to produce a vacuum, and a fresh jet of steam from the boiler was let in above the piston, which forced it again to the bottom of the cylinder. From an atmospheric it had thus become a true steam-engine, and with a much greater economy of steam than when the air did half the duty. But it was not only important to keep the air from flowing down the inside of the cylinder: the air which circulated within cooled the metal and condensed a portion of the steam within; and this Watt proposed to remedy by a second cylinder, surrounding the first with an interval between the two which was to be kept full of steam.

One by one these various contrivances were struck out, modified, settled, and reduced to definite plans; the separate condenser, the air and water pumps, the use of fat and oil (instead of water as in the Newcomen engine) to keep the piston working in the cylinder air-tight, and the enclosing of the cylinder itself within another to prevent the loss of heat. They were all but emanations from the first idea of inventing an engine working by a piston, in which the cylinder should be kept continually hot and perfectly dry. “When once,” says Watt, “the idea of separate condensation was started, all these improvements followed as corollaries in quick succession; so that in the course of one or two days the invention was thus far complete in my mind.”

The next step was to construct a model engine for the purpose of embodying the invention in a working form. With this object Watt hired an old cellar, situated in the first wide entry to the north of the beef-market in King Street, and there proceeded with his model. He found it much easier, however, to prepare his plan than to execute it. Like most ingenious and inventive men, Watt was extremely fastidious; and this occasioned considerable delay in the execution of the work. His very inventiveness to some extent proved a hinderance; for new expedients were perpetually occurring to him, which he thought would be improvements, and which he, by turns, endeavoured to introduce. Some of these expedients he admits proved fruitless, and all of them occasioned delay. Another of his chief difficulties was in finding competent workmen to execute his plans. He himself had been accustomed only to small metal work, with comparatively delicate tools, and had very little experience “in the practice of mechanics in great,” as he termed it. He was therefore under the necessity of depending, in a great measure, upon the handiwork of others. But mechanics capable of working out Watt’s designs in metal were then with difficulty to be found. The beautiful self-acting tools and workmanship which have since been called into being, principally by his own invention, did not then exist. The only available hands in Glasgow were the blacksmiths and tinners, little capable of constructing articles out of their ordinary walks; and even in these they were often found clumsy, blundering, and incompetent. The result was, that in consequence of the malconstruction of the larger parts, Watt’s first model was only partially successful. The experiments made with it, however, served to verify the expectations he had formed, and to place the advantages of the invention beyond the reach of doubt. On the exhausting-cock being turned, the piston, when loaded with 18 lbs., ascended as quick as the blow of a hammer; and the moment the steam-cock was opened, it descended with like rapidity, though the steam was weak, and the machine snifted at many openings.

Satisfied that he had laid hold of the right principle of a working steam-engine, Watt felt impelled to follow it to an issue. He could give his mind to no other business in peace until this was done. He wrote to a friend that he was quite barren on every other subject. “My whole thoughts,” said he, “are bent on this machine. I can think of nothing else.”[80] He proceeded to make another and bigger, and, he hoped, a more satisfactory engine, in the following August; and with that object he removed from the old cellar in King-street to a larger apartment in the then disused pottery or delftwork near the Broomielaw. There he shut himself up with his assistant, John Gardiner, for the purpose of erecting his engine. The cylinder was five or six inches in diameter, with a two-feet stroke. The inner cylinder was enclosed in a wooden steam-case, and placed inverted, the piston working through a hole in the bottom of the steam-case. After two months’ continuous application and labour it was finished and set to work; but it leaked in all directions, and the piston was far from air-tight. The condenser also was in a bad way, and needed many alterations. Nevertheless, the engine readily worked with 10½ lbs. pressure on the inch, and the piston lifted a weight of 14 lbs. The improvement of the cylinder and piston continued Watt’s chief difficulty, and taxed his ingenuity to the utmost. At so low an ebb was the art of making cylinders that the one he used was not bored but hammered, the collective mechanical skill of Glasgow being then unequal to the boring of a cylinder of the simplest kind; nor, indeed, did the necessary appliances for the purpose then exist anywhere else. In the Newcomen engine a little water was poured upon the upper surface of the piston, and sufficiently filled up the interstices between the piston and the cylinder. But when Watt employed steam to drive down the piston, he was deprived of this resource, for the water and the steam could not coexist. Even if he had retained the agency of the air above, the drip of water from the crevices into the lower part of the cylinder would have been incompatible with keeping the surface hot and dry, and, by turning into vapour as it fell upon the heated metal, it would have impaired the vacuum during the descent of the piston.

While he was occupied with this difficulty, and striving to overcome it by the adoption of new expedients, such as leather collars and improved workmanship, he wrote to a friend, “My old white-iron man is dead;” the old white-iron man, or tinner, being his leading mechanic. Unhappily, also, just as he seemed to have got the engine into working order, the beam broke, and having great difficulty in replacing the damaged part, the accident threatened, together with the loss of his best workman, to bring the experiment to an end. But though discouraged by these misadventures, he was far from defeated, but went on as before, battling down difficulty inch by inch, and holding good the ground he had won, becoming every day more strongly convinced that he was in the right track, and that the important uses of the invention, could he but find time and means to perfect it, were beyond the reach of doubt.

But how to find the means! Watt himself was a comparatively poor man; having no money but what he earned by his business of mechanical instrument making, which he had for some time been neglecting through his devotion to the construction of his engine. What he wanted was capital, or the help of a capitalist willing to advance him the necessary funds to perfect his invention. To give a fair trial to the new apparatus would involve an expenditure of several thousand pounds; and who on the spot could be expected to invest so large a sum in trying a machine so entirely new, depending for its success on physical principles very imperfectly understood?

There was no such help to be found in Glasgow. The tobacco lords, though rich, took no interest in steam power, and the manufacturing class, though growing in importance, had full employment for their little capital in their own concerns.

CHAPTER VIII.
Watt’s Connexion with Dr. Roebuck—Watt acts as Surveyor and Engineer.

Dr. Black continued to take a lively interest in Watt’s experiments, and lent him occasional sums of money from time to time to enable him to prosecute them to an issue. But the Doctor’s means were too limited to permit him to do more than supply Watt’s more pressing necessities. Meanwhile, the debts which the latter had already incurred, small though they were in amount, hung like a millstone round his neck. Black then bethought him whether it would not be possible to associate Watt with some person possessed of sufficient means, and of an active commercial spirit, who should join as a partner in the risk, and share in the profits of the enterprise. Such a person, he thought, was Dr. Roebuck, the founder of the Carron Iron Works, an enterprising man, of undaunted spirit, not scared by difficulties, nor a niggard of expense when he saw before him any reasonable prospect of advantage.[81]

Roebuck was at that time engaged in sinking for coal on a large scale near Boroughstoness, where he experienced considerable difficulty in keeping the shafts clear of water. The Newcomen engine, which he had erected, was found comparatively useless, and he was ready to embrace any other scheme which held out a reasonable prospect of success. Accordingly, when his friend Dr. Black informed him of an ingenious young mechanic at Glasgow who had invented a steam-engine, capable of working with increased power, speed, and economy, Roebuck immediately felt interested, and entered into correspondence with Watt on the subject. He was at first somewhat sceptical as to the practicability of the new engine, so different in its action from that of Newcomen; and he freely stated his doubts to Dr. Black. He was under the impression that condensation might in some way be effected in the cylinder without injection; and he urged Watt to try whether this might not be done. Contrary to his own judgment, Watt tried a series of experiments with this object, and at last abandoned them, Roebuck himself admitting his error.

Up to this time Watt and Roebuck had not met, though they carried on a long correspondence on the subject of the engine. In September, 1765, we find Roebuck inviting Watt to come over with Dr. Black to Kinneil (where Roebuck lived), and discuss with him the subject of the engine. Watt wrote to say that “if his foot allowed him” he would visit Carron on a certain day, from which we infer that he intended to walk. But the way was long and the road miry, and Watt could not then leave his instrument shop, so the visit was postponed. In the mean time Roebuck urged Watt to press forward his invention with all speed, “whether he pursued it as a philosopher or as a man of business.”

In the month of November following, Watt forwarded to Roebuck the detailed drawings of a covered cylinder and piston to be cast at the Carron Works. Though the cylinder was the best that could be made there, it was very ill-bored, and was eventually laid aside as useless. The piston-rod was made at Glasgow, under Watt’s own supervision; and when it was completed he was afraid to send it on a common cart, lest the workpeople should see it, which would “occasion speculation.” “I believe,” he wrote in July, 1766, “it would be best to send it in a box.” These precautions would seem to have been dictated, in some measure, by fear of piracy; and it is obvious that the necessity of acting by stealth increased the difficulty of getting the various parts of the proposed engine constructed. Watt’s greatest obstacle continued to be the clumsiness and inexpertness of his mechanics. “My principal hinderance in erecting engines,” he wrote to Roebuck, “is always the smith-work.”

In the mean time it was necessary for Watt to attend to the maintenance of his family. He found that the steam-engine experiments brought nothing in, while they were a constant source of expense. Besides, they diverted him from his retail business, which needed constant attention. It ought also to be mentioned that his partner having lately died, the business had been somewhat neglected and had consequently fallen off. At length he determined to give it up altogether, and begin the business of a surveyor. He accordingly removed from the shop in Buchanan’s Land to an office on the east side of King-street, a little south of Prince’s-street. It would appear that he succeeded in obtaining a fair share of business in his new vocation. He already possessed a sufficient knowledge of surveying from the study of the instruments which it had been his business to make; and application and industry did the rest. His first jobs were in surveying lands, defining boundaries, and surveyor’s work of the ordinary sort; from which he gradually proceeded to surveys of a more important character.

It affords some indication of the local estimation in which Watt was held, that the magistrates of Glasgow should have selected him as a proper person to survey a canal for the purpose of opening up a new coal-field in the neighbourhood, and connecting it with the city, with a view to a cheaper and more abundant supply of fuel. He also surveyed a ditch-canal for the purpose of connecting the rivers Forth and Clyde, by what was called the Loch Lomond passage; though the scheme of Brindley and Smeaton was eventually preferred as the more direct line. Watt came up to London in 1767, in connexion with the application to Parliament for powers to construct his canal; and he seems to have been very much disgusted with the proceedings before “the confounded committee of Parliament,” as he called it; adding, “I think I shall not long to have anything to do with the House of Commons again. I never saw so many wrong-headed people on all sides gathered together.” The fact, however, that they had decided against him had probably some share in leading him to form this opinion as to the wrong-headedness of the Parliamentary Committee.

Though interrupted by indispensable business of this sort, Watt proceeded with the improvement of his steam-engine whenever leisure permitted. Roebuck’s confidence in its eventual success was such that in 1767 he undertook to pay debts to the amount of 1000l. which Watt had incurred in prosecuting his project up to that time, and also to provide the means of prosecuting further experiments, as well as to secure a patent for the engine. In return for this outlay Roebuck was to have two-thirds of the property in the invention. Early in 1768 Watt made trial of a new and larger model, with a cylinder of seven or eight inches diameter. But the result was not very satisfactory. “By an unforeseen misfortune,” he wrote Roebuck, “the mercury found its way into the cylinder, and played the devil with the solder. This throws us back at least three days, and is very vexatious, especially as it happened in spite of the precautions I had taken to prevent it.” Roebuck, becoming impatient, urged Watt to meet him to talk the matter over; and suggested that as Watt could not come as far as Carron, they should meet at Kilsyth, about fifteen miles from Glasgow. Watt replied, saying he was too unwell to be able to ride so far, and that his health was such that the journey would disable him from doing anything for three or four days after. But he went on with his experiments, patching up his engine, and endeavouring to get it into working condition. After about a month’s labour, he at last succeeded to his heart’s content; and he at once communicated the news to his partner, intimating his intention of at last paying his long-promised visit to Roebuck at Kinneil. “I sincerely wish you joy of this successful result,” he said, “and hope it will make some return for the obligations I owe you.”

Kinneil House, to which Watt hastened to pay his visit of congratulation to Dr. Roebuck, is an old-fashioned building, somewhat resembling an old French château. It was a former country-seat of the Dukes of Hamilton, and is finely situated on the shores of the Frith of Forth. The mansion is rich in classical associations, having been inhabited, since Roebuck’s time, by Dugald Stewart, who wrote in it his ‘Philosophy of the Human Mind.’[82] There he was visited by Wilkie, the painter, when in search of subjects for his pictures; and Dugald Stewart found for him, in an old farmhouse in the neighbourhood, the cradle-chimney introduced in the “Penny Wedding.” But none of these names can stand by the side of that of Watt; and the first thought at Kinneil, of every one who is familiar with his history, would be of the memorable day when he rode over in exultation to wish Dr. Roebuck joy of the success of the steam-engine. His note of triumph was, however, premature. He had yet to suffer many sickening delays and bitter disappointments; for, though he had contrived to get his model executed with fair precision, the skill was still wanting to manufacture the parts of their full size with the requisite unity; and his present elation was consequently doomed to be succeeded by repeated discomfiture.

The model went so well, however, that it was determined at once to take out a patent for the engine. The first step was to secure its provisional protection, and with that object Watt went to Berwick-upon-Tweed, and made a declaration before a Master in Chancery of the nature of the invention. In August, 1768, we find him in London on the business of the patent. He became utterly wearied with the delays interposed by sluggish officialism, and disgusted with the heavy fees which he was required to pay in order to protect his invention. He wrote home to his wife at Glasgow in a very desponding mood. Knowing her husband’s diffidence and modesty, but having the fullest confidence in his genius, she replied, “I beg that you will not make yourself uneasy, though things should not succeed to your wish. If it [the condensing engine] will not do, something else will; never despair.” Watt must have felt cheered by these brave words of his noble helpmate, and encouraged to go onward cheerfully in hope.

He could not, however, shake off his recurring fits of despondency, and on his return to Glasgow, we find him occasionally in very low spirits. Though his head was full of his engine, his heart ached with anxiety for his family, who could not be maintained on hope, already so often deferred. The more sanguine Roebuck was elated with the good working of the model, and impatient to bring the invention into practice. He wrote Watt in October, 1768, “You are now letting the most active part of your life insensibly glide away. A day, a moment, ought not to be lost. And you should not suffer your thoughts to be diverted by any other object, or even improvement of this, but only the speediest and most effectual manner of executing an engine of a proper size, according to your present ideas.”

Watt, however, felt that his invention was capable of many improvements, and he was never done introducing new expedients. He proceeded, in the intervals of leisure which he could spare from his surveying business, to complete the details of the drawings and specification,—making various trials of pipe-condensers, plate-condensers, and drum-condensers,—contriving steam-jackets to prevent the waste of heat and new methods for securing greater tightness of the piston,—inventing condenser-pumps, oil-pumps, gauge-pumps, exhausting-cylinders, loading-valves, double cylinders, beams, and cranks. All these contrivances had to be thought out and tested, elaborately and painfully, amidst many failures and disappointments; and Dr. Roebuck began to fear that the fresh expedients which were always starting up in Watt’s brain, would endlessly protract the consummation of the invention. Watt, on his part, felt that he could only bring the engine nearer to perfection by never resting satisfied with imperfect devices, and hence he left no means untried to overcome the many practical defects in it of which he was so conscious. Long after, when a noble lord was expressing to him the admiration with which he regarded his great achievement, Watt replied: “The public only look at my success, and not at the intermediate failures and uncouth constructions which have served me as so many steps to climb to the top of the ladder.”

As to the lethargy from which Roebuck sought to raise Watt, it was merely the temporary reaction of a mind strained and wearied with long-continued application to a single subject, and from which it seemed to be occasionally on the point of breaking down altogether. To his intimate friends, Watt bemoaned his many failures, his low spirits, his bad health, and his sleepless nights. He wrote to his friend Dr. Small[83] in January, 1769, “I have many things I could talk to you about—much contrived, and little executed. How much would good health and spirits be worth to me!” A month later he wrote, “I am still plagued with headaches, and sometimes heart-aches.”

It is nevertheless a remarkable proof of Watt’s indefatigable perseverance in his favourite pursuit, that at this very time, when apparently sunk in the depths of gloom, he learnt German for the purpose of getting at the contents of a curious book, the Theatrum Machinarum of Leupold, which just then fell into his hands, and contained an account of the machines, furnaces, methods of working, profits, &c., of the mines in the Upper Hartz. His instructor in the language was a Swiss dyer,[84] settled in Glasgow. With the like object of gaining access to untranslated books in French and Italian—then the great depositories of mechanical and engineering knowledge—Watt had already mastered both those languages.

In preparing his specification, Watt viewed the subject in all its bearings. The production of power by steam is a very large one, but Watt grasped it thoroughly. The insight with which he searched, analysed, arranged, and even provided for future modifications, was the true insight of genius. He seems with an almost prophetic eye to have seen all that steam was capable of accomplishing. This is well illustrated by his early plan of working steam expansively by cutting it off at about half-stroke, thereby greatly economising its use;[85] as well as by his proposal to employ high-pressure steam where cold water could not be used for purposes of condensation.[86] The careful and elaborate manner in which he studied the specification, and the consideration which he gave to each of its various details, are clear from his correspondence with Dr. Small, which is peculiarly interesting, as showing Watt’s mind actively engaged in the very process of invention. At length the necessary specification and drawings were completed and lodged early in 1769,—a year also remarkable as that in which Arkwright took out the patent for his spinning-machine.

In order to master thoroughly the details of the ordinary Newcomen engine, and to ascertain the extent of its capabilities as well as of its imperfections, Watt undertook the erection of several engines of this construction; and during his residence at Kinneil took charge of the Schoolyard engine near Boroughstoness, in order that he might thereby acquire a full practical knowledge of its working. Mr. Hart, in his interesting ‘Reminiscences of James Watt,’ gives the following account: “My late brother had learned from an old man who had been a workman at Dr. Roebuck’s coal-works when Mr. Watt was there, that he had erected a small engine on a pit they called Taylor’s Pit. The workman could not remember what kind of engine it was, but it was the fastest-going one he ever saw. From its size, and from its being placed in a small timber-house, the colliers called it ‘the Box Bed.’ We thought it likely to have been the first of the patent engines made by Mr. Watt, and took the opportunity of mentioning this to him at our interview. He said he had erected that engine, but he did not wish at the time to venture on a patent one until he had a little more experience.”[87]

At length he proceeded to erect the trial engine after his new patent, and made arrangements to stay at Kinneil until the work was finished. It had been originally intended to erect it in the little town of Boroughstoness; but as prying eyes might have there watched his proceedings, and as he wished to avoid display, being determined, as he said, “not to puff,” he fixed upon an outhouse behind Kinneil, close by the burn-side in the glen, where there was abundance of water and secure privacy. The materials were brought to the place, partly from Watt’s small works at Glasgow, and partly from Carron, where the cylinder—of eighteen inches diameter and five feet stroke—had been cast; and a few workmen were placed at his disposal.

The process of erection was very tedious, owing to the clumsiness of the mechanics employed on the job. Watt was occasionally compelled to be absent on other business, and on his return he usually found the men at a standstill, not knowing what to do next. As the engine neared completion, his “anxiety for his approaching doom” kept him from sleep; for his fears, as he said, were at least equal to his hopes. He was easily cast down by little obstructions, and especially discouraged by unforeseen expense. Roebuck, on the contrary, was hopeful and energetic, and often took occasion to rally the other on his despondency under difficulties, and his almost painful want of confidence in himself. Roebuck was, doubtless, of much service to Watt in encouraging him to proceed with his invention, and also in suggesting some important modifications in the construction of the engine. It is probable, indeed, that but for his help, Watt could not have gone on. Robison says, “I remember Mrs. Roebuck remarking one evening, ‘Jamie is a queer lad, and, without the Doctor, his invention would have been lost; but Dr. Roebuck won’t let it perish.’”

The new engine, on which Watt had expended so much labour, anxiety, and ingenuity, was completed in September, 1759, about six months from the date of its commencement. But its success was far from decided. Watt himself declared it to be “a clumsy job.” His new arrangement of the pipe-condenser did not work well; and the cylinder having been badly cast, was found almost useless. One of his greatest difficulties consisted in keeping the piston tight. He wrapped it round with cork, oiled rags, tow, old hat, paper, horse-dung, and other things, but still there were open spaces left, sufficient to let the air in and the steam out. Watt was grievously depressed by his want of success, and he had serious thoughts of giving up the thing altogether. Before abandoning it, however, the engine was again thoroughly overhauled, many improvements were introduced in it, and a new trial was made of its powers. But this proved not more successful than the earlier ones had been. “You cannot conceive,” he wrote to Small, “how mortified I am with this disappointment. It is a damned thing for a man to have his all hanging by a single string. If I had wherewithal to pay the loss, I don’t think I should so much fear a failure; but I cannot bear the thought of other people becoming losers by my schemes; and I have the happy disposition of always painting the worst.”

Watt was therefore bound to prosecute his project by honour not less than by interest; and summoning up his courage, he went on with it anew. He continued to have the same confidence as ever in the principles of his engine: where it broke down was in workmanship. Could mechanics but be found capable of accurately executing its several parts, he believed that its success was certain. But there were no such mechanics then at Carron.

By this time Roebuck was becoming embarrassed with debt, and involved in various difficulties. The pits were drowned with water, which no existing machinery could pump out, and ruin threatened to overtake him before Watt’s engine could come to his help. He had sunk in the coal-mine, not only his own fortune, but much of the property of his relatives; and he was so straitened for money that he was unable to defray the cost of taking out the engine patent according to the terms of his engagement, and Watt had accordingly to borrow the necessary money from his never-failing friend, Dr. Black. He was thus adding to his own debts, without any clearer prospect before him of ultimate relief. No wonder that he should, after his apparently fruitless labour, express to Small his belief that, “of all things in life, there is nothing more foolish than inventing.” The unhappy state of his mind may be further inferred from his lamentation expressed to the same friend on the 31st of January, 1770. “To-day,” said he, “I enter the thirty-fifth year of my life, and I think I have hardly yet done thirty-five pence worth of good in the world; but I cannot help it.”

Notwithstanding the failure of his engine thus far, and the repeated resolution expressed to Small that he would invent no more, leading, as inventing did, to only vexation, failure, loss, and increase of headache, Watt could not control his irrepressible instinct to invent; and whether the result might be profitable or not, his mind went on as before, working, scheming, and speculating. Thus, at different times in the course of his correspondence with Small, who was a man of a like ingenious turn of mind, we find him communicating various new things, “gimcracks,” as he termed them, which he had contrived. He was equally ready to contrive a cure for smoky chimneys, a canal sluice for economising water, a method of determining “the force necessary to dredge up a cubic foot of mud under any given depth of water,” and a means of “clearing the observed distance of the moon from any given star of the effects of refraction and parallax;” illustrating his views by rapid but graphic designs embodied in the text of his letters to Small and other correspondents. One of his minor inventions was a new method of readily measuring distances by means of a telescope.[88] At the same time he was occupied in making experiments on kaolin, with the intention of introducing the manufacture of porcelain in the pottery work on the Broomielaw, in which he was a partner. He was also concerned with Dr. Black and Dr. Roebuck in pursuing experiments with the view of decomposing sea-salt by lime, and thereby obtaining alkali for purposes of commerce. A patent for the process was taken out by Dr. Roebuck, but eventually proved a failure, like most of his other projects. We also find Watt inventing a muffling furnace for melting metals, and sending the drawings to Mr. Boulton at Birmingham for trial. At other times he was occupied with Chaillet, the Swiss dyer, experimenting on various chemical substances; corresponding with Dr. Black as to the new fluoric or spar acid; and at another time making experiments to ascertain the heats at which water boils at every inch of mercury from vacuo to air. Later we find him inventing a prismatic micrometer for measuring distances, which he described in considerable detail in his letters to Small.[89] He was at the same time busy inventing and constructing a new surveying quadrant by reflection, and making improvements in barometers and hygrometers. “I should like to know,” he wrote to Small, “the principles of your barometer: De Luc’s hygrometer is nonsense. Probavi.” Another of his contrivances was his dividing-screw, for dividing an inch accurately into 1000 equal parts. He states that he found this screw exceedingly useful, as it saved him much needless compass-work, and, moreover, enabled him to divide lines into the ordinates of any curve whatsoever.

Such were the multifarious pursuits in which this indefatigable student and inquirer was engaged; all tending to cultivate his mind and advance his education, but comparatively unproductive, so far as regarded pecuniary return. So unfortunate, indeed, had Watt’s speculations proved, that his friend Dr. Hutton, of Edinburgh, addressed to him a New-year’s day letter, with the object of dissuading him from proceeding further with his unprofitable brain-distressing work. “A happy new year to you!” said Hutton; “may it be fertile to you in lucky events, but no new inventions!” He went on to say that invention was only for those who live by the public, and those who from pride choose to leave a legacy to the public. It was not a thing likely to be well paid for under a system where the rule was to be the best paid for the work that was easiest done. It was of no use, however, telling Watt that he must not invent. One might as well have told Burns that he was not to sing because it would not pay, or Wilkie that he was not to paint, or Hutton himself that he was not to think and speculate as to the hidden operations of nature. To invent was the natural and habitual operation of Watt’s intellect, and he could not restrain it.

Watt had already been too long occupied with this profitless work: his money was all gone; he was in debt; and it behoved him to turn to some other employment by which he might provide for the indispensable wants of his family. Having now given up the instrument-making business, he confined himself almost entirely to surveying. Among his earliest surveys was one of a coal canal from Monkland to Glasgow, in 1769; and the Act authorising its construction was obtained in the following year. Watt was invited to superintend the execution of the works, and he had accordingly to elect whether he would go on with the engine experiments, the event of which was doubtful, or embrace an honourable and perhaps profitable employment, attended with much less risk and uncertainty. His necessities decided him. “I had,” he said, “a wife and children, and saw myself growing grey without having any settled way of providing for them.” He accordingly accepted the appointment offered him by the directors of the canal, and undertook to superintend the construction of the works at a salary of 200l. a year. At the same time he determined not to drop the engine, but to proceed with it at such leisure moments as he could command.

The Monkland Canal was a small concern, and Watt had to undertake a variety of duties. He acted at the same time as surveyor, superintendent, engineer, and treasurer, assisted only by a clerk. But the appointment proved useful to him. The salary he earned placed his family above want, and the out-doors life he was required to lead improved his health and spirits. After a few months he wrote Dr. Small that he found himself more strong, more resolute, less lazy, and less confused, than when he began the occupation. His pecuniary affairs were also more promising. “Supposing the engine to stand good for itself,” he said, “I am able to pay all my debts and some little thing more, so that I hope in time to be on a par with the world.” But there was a dark side to the picture. His occupation exposed him to fatigue, vexation, hunger, wet, and cold. Then, the quiet and secluded habits of his early life did not fit him for the out-door work of the engineer. He was timid and reserved, and had nothing of the navvy in his nature. He had neither the roughness of tongue nor stiffness of back to enable him to deal with rude labour gangs. He was nervously fearful lest his want of practical experience should betray him into scrapes, and lead to impositions on the part of his workmen. He hated higgling, and declared that he would rather “face a loaded cannon than settle an account or make a bargain.” He had been “cheated,” he said, “by undertakers, and was unlucky enough to know it.”

Watt continued to act as engineer for the Monkland Canal Company for about a year and a half,[90] during which he was employed in other engineering works. Among these was a survey of the river Clyde, with a view to the improvement of the navigation. Watt sent in his report; but no steps were taken to carry out his suggestions until several years later, when the beginning was made of a series of improvements, which have resulted in the conversion of the Clyde from a pleasant trouting and salmon stream into one of the busiest navigable highways in the world.[91]

Among Watt’s other labours about the same period may be mentioned his survey of a canal between Perth and Cupar Angus, through Strathmore; of the Crinan Canal, afterwards carried out by Rennie; and other projects in the western highlands. The Strathmore Canal survey was conducted at the instance of the Commissioners of Forfeited Estates. It was forty miles long, through a very rough country. Watt set out to make it in September, 1770, and was accompanied by snowstorms through almost the entire survey. He suffered severely from the cold: the winds swept down from the Grampians with fury and chilled him to the bone. The making of this survey occupied him forty-three days, and the remuneration he received for it was only eighty pounds, which included expenses. The small pay of engineers at that time may be further illustrated by the fee paid him in the same year for supplying the magistrates of Hamilton with a design for the proposed new bridge over the Clyde at that town. It was originally intended to employ Mr. Smeaton; but as his charge was ten pounds, which was thought too high, Watt was employed in his stead. The Burgh minutes record that, after the Act had been obtained in 1770, Baillie Naismith was appointed to proceed to Glasgow to see Mr. Watt on the subject of a design, and his charge being only 7l. 7s., he was requested to supply it accordingly. “I have lately,” wrote Watt to Small, “made a plan and estimate of a bridge over our river Clyde, eight miles above this: it is to be of five arches and 220 feet waterway, founded upon piles on a muddy bottom.”[92] The bridge, after Watt’s plan, was begun in 1771, but it was not finished until 1780.[93]