Charles William Siemens was born at Lenthe in Hanover on April 4, 1823, and was one among many of a family eminent for their scientific knowledge and practical skill. The possession of such unusual talents by a whole family is rarer, perhaps, in the intellectual life of England than in that of Germany; at any rate, in the absence of definite statistics such as those compiled with so much care by Mr. Francis Galton, the general impression is that such is the case. It is not difficult to discern in the scientific career of the Brothers Siemens some prominent characteristics of their race; and in the life of Sir William, the sympathy of the German mind for general principles, and the tenacity with which it clings to them, are well illustrated, and stand out in strongly-marked contrast to the usual indifference of the average English mind to theoretic conclusions, as opposed to so-called practical ones. It would be well-nigh impossible to find among Englishmen one instance in which an inventor has been so confident of the possible utility of a few grand general principles, that he has worked out from them several great inventions; and that he felt himself justified in this confidence after years of hard work is evidenced by his own saying that “the farther we advance, the more thoroughly do we approach the indications of pure science in our practical results.”
William Siemens received his early educational training at Lübeck, and in the course of it the stimulus afforded to excellence of workmanship by the German guild system made an early and lasting impression upon his mind, for he repeatedly referred to it in after life. From Lübeck he went to the Polytechnical School at Magdeburg, where he studied physical science with apparatus of the most primitive kind, and under great disadvantages, as compared with the facilities of our modern laboratories. After this he studied at Göttingen University, where, under Wöhler and Himly, he first got that insight into chemical laws which laid the foundation of his metallurgical knowledge, and here began to develop in him that wonderful thirst for discovery, which abundant success never quenched. Here, also, occurred what he has himself described as “the determining incident of his life.” Mr. Elkington, of Birmingham, utilising the discoveries of Davy, Faraday, and Jacobi, had devised the first practical application of that form of energy which we now call the electric current, and in 1842 he established a practical process of electro-plating. In the following year, as the result of his own and his brother Werner’s work, William Siemens presented himself before Mr. Elkington with an improvement in his process, which was adopted. This is the first on the list of inventions on the diagram behind me. Speaking of his first landing in London he says:
“I expected to find some office in which inventions were examined, and rewarded if found meritorious; but no one could direct me to such a place. In walking along Finsbury Pavement, I saw written up in large letters so-and-so (I forget the name) ‘undertaker,’ and the thought struck me that this must be the place I was in quest of. At any rate I thought that a person advertising himself as an undertaker would not refuse to look into my invention, with a view of obtaining for me the sought-for recognition or reward. On entering the place I soon convinced myself, however, that I had come decidedly too soon for the kind of enterprise there contemplated, and finding myself confronted with the proprietor of the establishment, I covered my retreat by what he must have thought a very inadequate excuse.”
Returning to Germany, he became a pupil in the engine works of Count Stolberg, to study mechanical engineering. While there he worked out a great improvement upon Watt’s centrifugal governor for regulating the supply of steam to an engine, and in 1844 he returned to England with his invention, and soon decided to stay here. His object in doing so was to enjoy the security which the English patent law afforded to inventors, for in his own country there were then no such laws. This chronometric governor, though not very successful commercially, introduced him to the engineering world; it was originally intended for steam engines, but its chief application has been to regulate the movement of the great transit instrument at Greenwich. Then followed in quick succession several minor inventions which met with varying practical success, such as the process of anastatic printing, which was made the subject of a Royal Institution lecture in 1845 by Faraday; a water meter, which has since been in general use; an air pump, &c., &c.
About this time the researches of Joule, Carnot, and Mayer upon the relations between heat and mechanical work were attracting much attention among scientific men, and at the age of twenty-three, William Siemens adopted the hypothesis now known as the dynamical theory of heat. More than once I have drawn attention to the exact numerical relation between units of heat and units of work established by Joule, viz., that 772 foot-pounds of work is required to generate heat enough to raise the temperature of 1 lb. of water 1° Fah., and I have pointed out here and elsewhere that this was the first well-authenticated example of that grandest of modern generalisations, the doctrine of the Conservation of Energy, the truth of which is constantly receiving new illustrations.
With a mind thoroughly pervaded by this important principle, Siemens applied himself to the study of steam and caloric engines, and saw at once that there was an enormous difference between the theoretical and the actual power gained from the heat developed by the combustion of a given quantity of coal, and hence that there was a very large margin for improvement. He at once determined to try to utilise some of this wasted heat, and he conceived the idea (to which I invite your particular attention) of making a regenerator, or an accumulator, which should retain or store a limited quantity of heat, and be capable of yielding it up again when required for the performance of any work. In the factory of Mr. John Hicks, of Bolton, he first constructed an engine on this plan; the saving in fuel was great, but it was attended by mechanical difficulties which at that time he was unable to solve. The Society of Arts, however, recognised the value of the principle by awarding him a gold medal in 1850. Three years afterwards, his paper “On the Conversion of Heat into Mechanical Effect,” before the Institution of Civil Engineers, gained him the Telford premium (awarded only once in five years) and the medal of the Institution. In 1856 he gave a lecture upon his engine at the Royal Institution, considered as the result of ten years’ experimental work, and as the first practical application of the mechanical theory of heat; he then indicated the economic considerations which encouraged him to persevere in his experiments, pointing out that the total national expenditure for steam-coal alone amounted to eight millions sterling per year, of which at least two-thirds might be saved!
His efforts to improve the steam-engine, however, were speedily followed by a still more important application of the mechanical theory of heat to industrial purposes. In 1857 his younger brother, and then pupil, Frederick (who, since the death of Sir William, has undertaken the sole charge of the development of this branch of his elder brother’s work), suggested to him the employment of regenerators for the purpose of saving some of the heat wasted in metallurgical operations, and for four years he labored to attain this result, constructing several different forms of furnace. His chief practical difficulties arose from the use of solid fuel—coal or coke—but when, in 1859, he hit upon the plan of converting the solid fuel into gaseous, which he did by the aid of his gas-producer, he found that the results obtained with his regenerators exceeded his most sanguine expectations. In 1861 the first practical regenerative gas furnace was erected at the glass works of Messrs. Chance Bros. in Manchester, and it was found to be very economical in its results. Early in 1862 the attention of Faraday was drawn to this matter, and on June 20 of the same year, that prince of experimentalists appeared before the Royal Institution audience for the last time to explain the wonderful simplicity, economy, and power of the Siemens regenerative gas furnace. Age and experience have not diminished the high estimation in which it is held; after nearly twenty years of continuous working and extended application, Sir Henry Bessemer described it in 1880 as an “invention which was at once the most philosophic in principle, the most powerful in action, and the most economic, of all the contrivances for producing heat by the combustion of coal.”
The furnace consists essentially of three parts; (1) the gas producer, which converts the solid coal into gaseous fuel; (2) the regenerators, usually four in number, which are filled with fire-brick piled in such a way as to break up into many parts a current of air or gas passing through them; (3) the furnace proper, where the combustion is actually accomplished. In using the furnace, the gaseous fuel and air are conducted through one pair of regenerators to the combustion chamber; the heated gases from this, on their way to the chimney, pass through the other pair of regenerators, heating them in their passage. In the course of, say, one hour, the currents are reversed, so that the comparatively cold gas and air pass over these heated regenerators before entering the furnace, and rob them of their heat. While this is going on, the first pair of regenerators is being heated again, and thus, by working them in alternate pairs, nearly all the heat, which would otherwise have escaped unused into the chimney, is utilised.
By this process of accumulation the highest possible temperature (only limited by the point at which its materials begin to melt), can be obtained in the furnace chamber, without an intensified draft, and with inferior fuel.
It has been found that this furnace is capable of making a ton of crucible steel with one-sixth of the fuel required without it, and that while the temperature of the furnace chamber exceeded 4,000° Fahrenheit, the waste products of combustion escaped into the chimney at 240° Fahrenheit, or very little above the temperature at which water boils in the open air.