Lord Dundonald's father, the ninth earl, had devoted the chief energies of his long life to scientific pursuits, which won for him, not profit, but well-earned fame, and which proved of immense benefit to his own and succeeding generations. By him was discovered the art of extracting tar from coal, and out of that discovery was developed, partly by him and partly by others, the manufacture of gas, first used for lighting his tar-works. The important chemical process of making alkali and crystals of soda was also introduced by him, whereby a great impetus was given to the manufacture of glass and to many other important branches of industry. He discovered the present method of preparing alum, or sulphate of vitriol, and suggested its substitution for gum senegal, which has proved hardly less advantageous to the mechanical arts. In 1795, he published a treatise, the result of numerous and costly experiments, on the connection between agriculture and chemistry, which was almost the parent of all the later researches that have issued in beneficial plans for improving the soil and invigorating the growth of crops, and in various and important developments of scientific farming.
The tenth Earl of Dundonald inherited his father's mechanical and scientific genius. The lamp invented by him in 1814, which introduced the principle upon which all later lamps for burning oil, naphtha, and other combustibles have been constructed, has been already referred to. Many other inventions and discoveries occupied his leisure during the years in which he was allowed to follow his profession both in British and in foreign service;[15] and the fuller leisure forced upon him during the years following his return from Greece was chiefly devoted to further exercise of his inventive faculties.
To the wonderful invention known as his "secret war-plan" allusion will presently be made. His other most important mechanical pursuits had for their principal object the improvement of steam-engines and other appliances for steam-shipping. Almost his first reminiscence was of a visit in which, when he was seven or eight years old, he accompanied his father to Birmingham, there to meet with James Watt, and hear something of his memorable discovery. Apprehending in his youth the value of that discovery, he never wearied in his efforts to extend its usefulness. The Rising Star, built in 1818 under his directions, and those of his brother, Major Cochrane, for service in Chili, was the first steam-vessel that crossed the Atlantic, and it was an additional disappointment to him, amid all the misfortunes incident to his efforts to give adequate assistance to the Greeks in their war of independence, that the ill-fated steamers which were to be his chief instruments therein, failed through the indolence and incompetence of those to whom their construction was assigned.
It is not necessary here to detail the studies and experiments by which he afterwards sought to introduce a better steam-engine, for locomotive purposes, than was then, or is even now, in general use. His plan—not a new one, though it had never before been made available in practice—was to substitute for the ordinary reciprocating engine a machine which should at once produce a circular motion. "Of the many rotary engines heretofore offered to the notice of the world," he wrote, in 1833, "none have stood the test of practical use and experience. The cause of this uniform failure has been the great difficulty of obtaining, within the machine, a base of resistance on which the steam might act in propelling the moveable piston." He did not quite overcome this difficulty, but he succeeded in producing what the foremost critic in this department of manufacture describes—after a lapse of thirty years unrivalled for their development of ingenuity—as "the most perfect engine of the class that has yet been projected."
"In this engine," says the same authority, "an eccentric is made to revolve on an axis in the manner of a piston, and two doors, forming part of the side of the cylinder, press upon the eccentric. The points of these doors are armed with swivelling brasses, which apply themselves to the eccentric and make the point of contact tight in all positions."[16]
"This revolving engine," said Lord Dundonald, "does not require any valve or slide; consequently, there is no waste of steam thereby; neither is there any loss, as in the space left at the top and bottom of the cylinders of reciprocating engines. There is much less friction than arises from the sum of all the bearings required to convert the rectilineal force of the common engine to circular motion. There are no beams, cranks, side-rods, connecting-rods, parallel motions, levers, slide-valves, or eccentrics, with their nicely-adjusted joints and bearings; and thus the revolving engine is not liable, even in one-tenth degree, to the accidents and hindrances of other engines. As its moving parts pursue their course in perfect circles, without stop or hindrance, it is capable of progressive acceleration, until the work performed equals the pressure of steam on the vacuum—an advantage which the reciprocating engine does not possess. The diminished bulk and weight, and the absence of tremor, add to the capacity, buoyancy, velocity, and durability of vessels in which it is placed." The rotary engine did not satisfy all Lord Dundonald's expectations, but it took precedence of all others of the same sort, and was of great service at any rate in directing attention to what he rightly considered to be the great want in war-shipping, namely, vessels of the least possible bulk and of the greatest possible strength, speed, and fighting power.
Years were spent by him in attempting to bring it into notice. At his own cost he fitted out a little steamboat, which navigated the Thames; but to perfect the invention were required more funds than he had at his command, and he sought in vain for adequate assistance from others.
In January, 1834, he wrote to Sir James Graham, then First Lord of the Admiralty, thanking him for his share in the restitution of his naval rank that had occurred nearly two years before, and urging the co-operation of the Government in perfecting an invention that promised to be of so much importance to the naval power of England. "You are not obliged to me for anything," answered Sir James on the 15th; "I only am fortunate in being the member of a Government which has regained for our country the benefit of your distinguished valour and services, which, if again required in war, will, I am persuaded, be so exerted as to win the gratitude of the nation, and to demonstrate the justice of the decision to which you allude. It is impossible to over-estimate the paramount importance of steam in future naval operations; and it is fortunate that you have directed so much of your attention to the subject. The Board has complied with your request, and two engineers, in whom we place reliance, will be ordered to attend you." It does not appear, how-ever, that the engineers did attend. At any rate, nothing was done by the Admiralty in aid of the invention either then or for many years after.
Yet its ingenuity was acknowledged by all who investigated it, and by naval authorities among the number. The Earl of Minto, when First Lord of the Admiralty, sought to introduce it into the national ship-building; but official hindrances, too great even for him to overcome, stood in his way. All he could do was to have it referred to competent judges and to receive their report in its favour. "I am commanded to acquaint your lordship," wrote Sir John Barrow, the Secretary to the Admiralty, to the Earl of Dundonald, on the 20th of December, 1839, "that the opinions received of your revolving engine are favourable to the principle, and that it has not been stated that there are any insurmountable obstacles to its practical execution." The insurmountable obstacles were in the stolid resistance of subordinates to any novelty designed to lessen labour and promote economy.
Lord Minto, when out of office, was able to speak of the engine in more approving terms than he could adopt in his official capacity. "I need hardly say," he wrote on the 6th of September, 1842, "that the report of continued success in your rotatory engine gives me great pleasure, not only upon your own account, but as promising a valuable addition to our naval power in its application to ships of war. As a high-pressure engine, the complete success of your plan has, I believe, been recognised by all who have attended to it, and it is in this form that I had contemplated its application in the first instance as an auxiliary and occasional power in some ships of war."