August 24, 1893] 



NATURE 



397 



great town then possessed ; Arago, Dulong, Fresnel, 

 Fourier, Ampere. He made true friends with many of 

 them, and had the honour of being a fellow-worker of 

 the two last. At Paris he found the old friend of his 

 childhood, Sturm, with whom, in 1826, he made the 

 wonderful experiments on the Lake of Geneva, relating 

 to "the velocity of sound in water," which united their two 

 names so admirably in all treatises on physics, and which 

 won for them the grand prize of the Institute of France. 



By the side of these classical researches, Colladon's 

 first works deal chiefly with electricity. In 1826 he pub- 

 lished his experiments made at the College of France, 

 with a galvanometer of his own invention, on the mag- 

 netic actions which ordinary electrical machines, Leyden 

 batteries, and atmospheric electricity produce on the 

 magnetic needle. He studied the electrodynamic actions 

 with Ampere, and the conductivity of thin bodies for heat 

 with Fourier. 



The celebrity which he had acquired for himself at 

 Paris by his works led to his being asked by the 

 founders of the Central School of Art and Manufac- 

 ture to join them, and to give a special course of 

 lectures on the steam engines and their use, which he 

 did with much success from 1831 to 1834. He also made 

 numerous researches and inventions relating to steam- 

 engines. In 1844 the Lords of the English Admiralty 

 adopted a dynamometer which he invented to measure 

 the effective power of steam-engines for navigation, and 

 which he was charged to make at the Royal Arsenal of 

 Woolwich at the cost of the Admiralty. 



In spite of the honourable place which he had attained 

 at Paris in the world of science and industry, Colladon, 

 was so attached to his country, that he gave up the 

 many advantages which would accrue from a residence 

 in France, and settled at Geneva in 1834. He proved 

 himself on many occasions most useful in the debates 

 of the little Republic, and was made Professor of the 

 Academy in 1839 



In 1852 he rendered to the industry of his country 

 the great service of representing it at the first Universal 

 Exhibition in London, where he was delegated by the 

 Federal Council as Commissioner for Switzerland. 



He took part in two juries relating respectively to 

 physical instruments and clocks. The most diver* 

 branches of industry e.tcited the interest and research 

 of his fruitful mind. One to which he gave most of his 

 attention was illumination by gas. In 1844 he was ap- 

 pointed engineer of the new gas company at Geneva. He 

 invented a great number of improvements in gas-lighting, 

 and the wonderful competence that he acquired has con- 

 tributed largely to establishing a great number of enter- 

 prises of the same sort both in Switzerland and abroad. 

 It was on this account that he was charged to super- 

 intend the installation of the Gas Society at Naples. 



Hydraulics occupied him on many occasions ; he 

 studied the water supply of towns, and invented floating 

 hydraulic wheels with the paddles below. It was he who 

 discovered the ingenious way of lighting a liquid tube 

 from within, by introducing, as it were, with the water a 

 luminous ray, which remains imprisoned by the effects 

 of totally multiple reflections, and illuminates the 

 whole length of the liquid cylinder. The luminous 

 fountain, or, as it is often called, " the Colladon fountain," 

 originated from this delicate experiment. It formed one 

 of the most beautiful ornaments at the Universal Exhibi- 

 tion at Paris, and was tried on a larger scale for the first 

 time at the exhibition of Glasgow in 1884. 



But these are not the inventions which render great 

 the name of their inventor ; the one which merits this 

 honour, and to which the name of Colladon must ever 

 be united, is that of the use of compressed air for the 

 transference of energy. Profiting by the resources which 

 hehadathis disposal as engineer of the gas works at 

 Geneva, from 1849 he made essays on the circulation of 



NO. I 243. VOL. 48] 



compressed gas in pipes, and he demonstrated the possi- 

 bility of transmitting with economy a considerable energy 

 for a long distance in narrow pipes. It is easy to under- 

 stand the immense importance in the construction of long 

 tunnels of transmitting energy by compressed air, for 

 with the impulse given to the boring machine, fresh air is 

 brought at the same time to the workmen at the end of 

 the deep galleries. It is this idea, as simple as it is 

 beautiful, which constitutes Colladon's claim to glory ; 

 this invention which must immortalise his name : it is 

 this which makes it possible to construct the great sub- 

 terranean passage which honour our generation, and 

 which have made him one of the benefactors of our time. 

 After the first studies for the tunnel of Mont Cenis, in 

 December, 1852, he gave an excellent memoir on the 

 subject to the Financial Minister of the Italian State 

 which was followed by a request for a patent for the new 

 processes. 



This important memoir, transmitted by the Italian 

 Government to the Royal Academy of Science at Turin, 

 was the object of a special report addressed to the 

 Minister, and it concluded thus : 



" The author does not limit his memoir to a simple 

 description of the proposed scheme, but he shows the 

 applicability by theoretical considerations. The commis- 

 sion recognises above all the vast importance the in- 

 ventions of Monsieur Colladon could be in hastening the 

 construction of the railways destined to cross the Alps." 

 The splendid invention of Colladon was applied with 

 much success by the Italian engineers at the construction 

 of the Mont Cents tunnel, and it made its reputation 

 there, but all the honour belongs to the discoverer. If 

 Colladon had not the pleasure of making the first appli- 

 cations of his invention, and if he had to leave to others 

 the honour of making the first sub-alpine tunnel, he 

 was able at least to give his ideas full development in the 

 making of the St. Gothard tunnel, by the installation of 

 the powerful compressors at Goeschenen and Airolo, 

 which he executed for the enterprise directed by L. Favre. 



Colladon was one of the first specialists in the art 

 of constructing tunnels. It is owing to this that in 1878 

 he was made a member of the committee connected with 

 the tunnel under the Channel. He was also very busily 

 occupied studying out the boring of the Simplon. 



We cannot in this short notice give a complete idea of the 

 greatness, and fruitfulness of Colladon's career. Suffice 

 it to mention his researches on the electricity of the 

 torpedo, atmospheric electricity, the effect of lightning 

 on trees, snow and hail, waterspouts, the use of steam 

 for putting out fires, and on the terraces surrounding 

 the Lake of Geneva. 



Colladon had such a many-sided mind, that he could 

 interest himself with the most diverse questions, and he 

 studied them all with remarkable care and conscien- 

 tiousness. Absolutely disinterested, he worked for the 

 advancement of science, without pushing his inventions 

 for his own profit. On the contrary, he was always 

 at the service of others, and always ready to help 

 them with his advice and assistance without any 

 remuneration. 



He was a great worker and was willing to assist 

 others until the last years of his admirable life. He died 

 at the age of ninety-one, preserving nearly to the last 

 the use of his fine and noble faculties. His reputation 

 had extended itself far and wide, and a great number ot 

 learned societies of all parts of the world counted him 

 among the number of their members. 



Ed. S.A.RAS1N. 



NOTES. 

 We learn that Dr. J. W. Gregory arrived at Mombasa on 

 August 19, after a successful expediticn to Lake Baringo. He 

 returned via Likipia and Mount Kenia, and ascended the latter 



