W. Siemens, the subject of this memoir, has been for many years a naturalised Briton. Nevertheless, such men are of no particular nation, for their talents are employed all over the world, and their discoveries and inventions go to swell the resources of humanity in general. For of them the remark is eminently true that whatever may be the benefits which they personally reap from their exertions, these could not accrue to them unless the benefit to mankind were from ten to a thousandfold greater.

Charles William Siemens was born at Lenthe in Hanover, on the 4th April, 1823. His school days were spent at Lubeck, whence he went to the Magdeburg Polytechnical School to study engineering. We find him in the University of Göttingen in 1842, and after his mathematical course there, he entered the Engine Works of Count Stolberg. Here he learned the practical use of tools, and became well versed in engineering knowledge. He came to England in 1843, in order to introduce a process of electroplating and gilding, the joint invention of himself and his elder brother, Werner Siemens. He returned to Germany in the same year, and perfected with his brother their differential governor for steam engines, known as the chronometric governor, the free action of which produces by its differential motion a regulating action. This governor has been extensively applied to steam engines, both stationary and marine, and is used in the Royal Observatory of Greenwich, to regulate the motion of the Equatorial instruments. For this invention he took out a patent in England, and finding that in this country he could obtain the protection for his inventions which his own land refused to afford generally, though at times it might be granted for short periods, he determined to pursue his career of invention in England, where he might make himself certain of protection for at least fourteen years. He accordingly settled in this country in 1844, and in the same year brought out the anastatic process of printing, like the two former inventions, the joint property of his brother and himself. By this process, printed matter was reproduced with accuracy, whether it were old or new. It consisted in converting the resinous constituents of the printing ink into an insoluble soap, and then precipitating the stearine by means of sulphurous acid. Thus the printed matter was transformed to zinc. About the same time he was engaged upon railway works,

and effected considerable improvements in Hoyle's calico printing works, and perfected his double cylinder air pump, which was very successful, as well as an excellent water meter which was extensively adopted. It was in 1846 that he began to study the dynamic theory of heat with a view to promote the economy of fuel, to which his inventions and researches have contributed more than those of any other man. Little at that period was known on the subject. Men had treated the steam engine as a useful giant, feeding it recklessly, and heedless of waste, while little attention had been turned to economy of fuel. True, in Cornwall and in other places where the price of coal was largely enhanced by the cost of transport, some furnaces of more economic construction than usual had been employed, and condensers had been invented and used in most places, still as regarded smelting works and other great fuel consuming industries, nothing had as yet been done to carry out the philosophical suggestion of Dr. Sterling of Dundee, thirty years before, that heat might be accumulated and made afterwards available. Mr. Siemens at twenty-three years of age, entered on the study of this problem, to which he brought the valuable, persevering, and exhaustive powers of the Teutonic mind, and having mastered all that could be found in the treatises of Joule, Carnot, Clapeyron, Mayer, and other authorities on the subject, he proceeded to experiment by the light of this knowledge. He found that the theoretic power of the heat employed was considerably less than the results produced in the mechanical power of the engines to which it was applied, and he determined to attempt to save up at least a portion of the surplus heat, by means of a regenerator. His first attempt at a practical solution of this important matter, was a regenerative engine, worked by superheated steam in the factory of Mr. John Hick, of Bolton, which was completed in 1847. This was a four-horse engine, and was not unsuccessful in saving a considerable amount of fuel, but there remained certain mechanical difficulties in the way of a great success. He was determined to conquer these, and continued to devote attention to the subject, on which he read a paper for the Institution of Civil Engineers in 1852, suggesting by a more extended application of the principle of the expansion of heat, a much larger proportion of the heat applied could be utilised as mechanical power.

In the Paris Exhibition of 1857 he fitted up a 20-horse engine, with an improved heat regenerator; this did not come up to his expectations, but he got excellent results from the employment of this regenerator with a 7-horse engine. This tended to show that his views as to regeneration or recuperation were correct, and with the aid of his younger brother, Frederick, he continued his series of costly experiments on the subject. The history of this great invention is highly instructive; he obtained success at one point but to discover some fresh obstacle at another. On looking at obstacles, however, as matters to be destroyed or overcome, he steadily set himself as each new difficulty arose to find the means of removing it. The struggle lasted for fourteen weary years, but in the end he reaped the reward of complete success in the Regenerative Gas Furnace-an invention which has placed his name on the roll of great practical scientific benefactors. Keeping in view his ideas as to the degeneration of heat, he conceived that in order to obtain the best results of combustion, the solid fluid must be converted into gas; he therefore placed a gas producer before the furnace into which he conducted the crude gas, through a sunk chamber called the regenerator. The chamber is made of fire-bricks, so put together as to break up the current of gas or air as much as possible, and beneath the furnace are placed four of these regenerators, through which the currents can be directed either upwards or downwards at pleasure, by means of valves. The gas from two of these chambers is directed into the furnace when it is lighted, and the current on leaving the furnace then passes through the two other chambers, heating the complicated brickwork till that portion nearest the furnace rises to almost the temperature of the furnace itself, while the further extremity, having less heat left to absorb, is nearly cool, and the draught passes into the chimney after having deposited a very large proportion of its heat. After this has been continued for some time, the currents are reversed, and the gas, now introduced into the cooler end of the heated regenerator, becomes heated as it passes through and enters the furnace at nearly the temperature of its heated chamber. Thus the heat of the furnace is about doubled, and the heated stream is conducted from it through the other two regenerators, heating them and escaping comparatively cool into the chimney. The mea

surement of the heat of these streams showed that while the heat in the furnace exceeded 3000° Fahr., the temperature of the stream entering the chimney was but 300°, and the result obtained paractically was that this regenerator saved in important operations (such as melting steel) about two thirds of the fuel needed without it. It had the further advantages of a capacity to use inferior fuel and of allowing no carbon to escape in the form of smoke. Although this invention has been most successful, Dr. Siemens still hopes to make it more practically valuable. He looks forward to a time when he believes this crude gas will be made at the bottom of coal pits and conducted to where it is wanted; and such a system would ensure good ventilation in the pits and would utilise much of the small coal which now is not considered worth bringing to the surface. He proposed a plan for lighting Birmingham with gas at a cheap rate made on this plan, but the Committee of the Lords, in 1863, on considering a Bill for the purpose, took the sapient view that existing gas companies would be certain to adopt the plan if it were as good as it was said to be.

From the successful working of this regenerative furnace to its employment in the condition of an open hearth for the production of steel, the steps appeared easy; but it was soon found that they were not so. In 1862 such a furnace was designed for a Durham ironmaster, but it did not succeed completely. In 1863 Siemens designed a furnace which was built in France, at the Montluçon works, when a series of experiments was made, and also some excellent steel; but owing to an accident the furnace was abandoned. Enough had, however, been accomplished to induce Dr. Siemens to presume with increased confidence as to the ultimate results, and he took his now memorable "Sample Steelworks" at Birmingham, where he undertook a further series of experiments.

With the experience thus obtained he was enabled in 1866 to design a furnace for a Glasgow house, which, however, was given up after being tried for a few days only. The Barrow Steel Company were more successful in 1867, but did not find that there was sufficient profit to be obtained in making good steel by this process. A similar result followed a trial at the Bolton Steel Works. Nothing, however, could daunt the inventor, and he continued to work in Birmingham confident of succeeding at last. His

process there was examined by Mr. Ramsbotham, Engineer of the London and North Western Railway Company, who was so well satisfied with it that he adopted it at the works of the Company at Crewe in 1868. In the same year the Great Western Railway Company sent some old iron rails to be converted into steel at the Birmingham Works. Some of these were so converted and laid down with perfect success, lasting for ten years afterwards. The success of this experiment led to the formation of the Landore Siemens' Steel Company, of which Mr. L. L. Dillwyn, M.P., was Chairman, and the Messrs. Martin of Sireuil at the same time succeeded in making steel in a Siemens' furnace by melting wrought iron and scrap in a bath of pig metal. This became known as the scrap process, the direct process being the fusion of pig metal with iron ores, but the process was not perfected till 1873. Thus his fourteen years labour, which was rewarded in 1861 by the perfection of the regenerative gas furnace, was followed by another twelve years of experiments and partial failures, to be crowned by the success of his Siemens' steel process. His success is an evidence of his patient and persevering spirit, and of his energy, directed by a mind fully imbued with the scientific knowledge which enabled him to comprehend on examination the causes of failure, and to design means for their removal.

But it must also be remembered that a large share of this success is due to the English patent laws, for he himself told the Parliamentary Committee on this question, that he would not have continued such costly and protracted experiments but for the certainity that these laws would secure him a remuneration for his labours. And, notwithstanding the admirable and remarkable Bessemer* process with which he competes, his system has made great progress, and the process is being extensively employed on the Continent and in the United States. His mild steel is now exclusively used for the boilers and the hulls of the ships built in the Royal dockyards, as well as for the decks of armour-plated ships.

The contributions of Dr. Siemens to the progress of mechanical and metallurgical industry, form, however, but one section of his work, for the fame which he has acquired for his success in the practical application of electricity,

* For memoir of Sir Henry Bessemer, see page 77, May.