8 34 THE POPULAR SCIENCE MONTHLY. 



house in Berlin for the use of his plating apparatus, and Wilhelm 

 was dispatched to England to introduce the inventions there. 

 Besides the galvano-plating patent, which was sold to Elkington 

 & Co. for £1,500, there were processes for nickel-plating and for 

 anastatic printing, etc. A journey to London to assist Wilhelm 

 in some financial difficulty, in which he visited Paris and Brussels 

 on his return, gave him new and higher views of his work, while 

 its results satisfied him that the road to wealth did not lie 

 through speculation in inventions. He entered upon a more 

 thorough course of study, formed associations with the young 

 naturalists of the time, some of whom have since become famous, 

 joined in the foundation of the Physical Society, interested him- 

 self in the Polytechnic Society, and sought to promote the tech- 

 nical applications of science. He became acquainted with manu- 

 facturers, and published articles in the scientific journals on "The 

 Application of Hot Air as a Motive Power," in which he accepted 

 Mayer's and Helmholtz's doctrine of the conservation of force ; 

 describing his differential regulator ; and " On the Application of 

 the Electric Spark to the Measurement of Velocity." 



Werner Siemens became warmly interested in the experiments 

 which Leonhardt was making, at the instance of the general staff 

 of the army, in the substitution of an electrical apparatus for opti- 

 cal telegraphy. He had seen a model of Wheatstone's telegraph 

 in the house of one of his comrades, and had tried to establish a 

 communication between the house and a mineral-water establish- 

 ment across the garden. He devised an improvement in the ap- 

 paratus for generating and controlling the current, which at- 

 tracted the attention of the mechanician Halske, who eventually 

 gave up his business and associated himself with Siemens in teleg- 

 raphy. 



Siemens's plans were again embarrassed by the results of his 

 and his companions' inconsiderately signing a paper connected 

 with the religious movement of John Ronge, which was consid- 

 ered seditious. His brigade, to punish the offenders, was ordered 

 to a retired post. It was important for him to remain in Berlin 

 to prosecute his researches, and he devised a means to induce the 

 Government to keep him there. Schonbein had made his first 

 discovery of gun-cotton, but the material he produced was poor 

 and unreliable. Siemens spent a day in experimenting upon it ; 

 added treatment with sulphuric acid, and obtained a certain and 

 really practicable explosive. He communicated his discovery to 

 the Minister of War, and was ordered to continue his experiments 

 at the Spandau Arsenal, while his punishment was forgotten. 

 Unfortunately, Prof. Otto, of Brunswick, who had independently 

 discovered the same method, anticipated him in publication, and 

 thus deprived him of the credit of priority. 



