MICHAEL FARADAY — HIS LIFE AND WORKS. "^^ 



The discovery of this Ijicarburet of hydrog-eii was only an incident in the 

 researches which Faraday had undertaken in 1823, upon the condensation of 

 gases into liquids. His mode of operation in this investigation consisted in 

 placing in one extremity of a recurved tube, closed at both ends, the necessary 

 ingredients for the production of the gas, and plunging the other extremity in a 

 freezing mixture. The gas, evolved in a closed space, speedily condensed into 

 a liquid state in the refrigerated extremity of the tube. In this way chlorine, 

 sulphurous acid, sulphuretted hydrogen, carbonic acid, protoxide of nitrogen, 

 cyanogen, ammonia, and hydrochloric acid were successively reduced to a liquid 

 state. With the exception of chlorine, all these liquefied gases were colorless 

 and perfectly transparent ; and all of them had a refractive power superior to 

 that of water. The attempts made to reduce the other gases, especially hydro- 

 gen, oxygen, and nitrogen to a liquid state were fruitless. Twenty years later 

 (in 184'4) Faraday resumed these experiments by directly condensing the gases 

 by mechanical processes in very strong and hermetically sealed tubes, refrige- 

 rating them liy means of the mixture of ether with solid carbonic acid pro- 

 duced by Tliilorier's method. The condensation could be brought to fifty 

 atmospheres, and the lowering of temperature to — 166°F., or 110°C. below 0°. 

 In this way Faraday succeeded in liquefying, besides the gases which I have 

 already mentioned,* olefiant gas, phosphuretted hydrogen, and arseniuretted 

 hydrogen, as also fluosilicic acid ; but he did not succeed in solidifying them. 

 On the other hand, by applying his new process to the gases which he had pre- 

 viously liquefied, he l)rought them not only to a liquid state, but even to that 

 of transparent and crystalline solids ; hydrochloric gas alone of these latter 

 would not become solid, whilst hydriodic and hydrobromic gas were successively 

 liquefied and solidified. 



It is easy to understand all the importance of an investigation the result of 

 which was'to modify completely tlie received ideas as to the constitution of the 

 permanent gases by causing them to enter into the category of simple vapors ; 

 this was to introduce into molecular physics a new and important notion, the 

 consequences of which have gradually unfolded themselves. 



It is also to a question of molecular physics that we must refer the meuKjir 

 on the relations of gold and the other metals to light, published by Faraday in 

 1857. Among other interesting facts that this memoir contains, we shall cite 

 that of a leaf of beaten gold, which, when placed upon a plate of glass, 

 becomes perfectly transparent and colorless when it is brought to a high tem- 

 perature, and which, when seen by transmitted light, resumes its green color 

 when it is subjected to- strong pressure. A great number of experiments upon 

 the pulverulent deposits of various metals obtained by electrical discharges 

 transmitted through very fine wires, led to remarkable results as to the varia- 

 tions of color arising from change in the molecular state of the same body. We 

 also find in this memoir a detailed investigation of the various colors presented 

 by difi'erent solutions of gold, and especially of the fine ruby-red tinge obtained 

 by the solution of a quantity of gold whicli, if agglomerated into a single mass, 

 would not occupy the seven-hundred-thousaiKlth part of the volume of water 

 which it colors, "it is not necessary to dwell upon the interest presented by 

 researches having for their object the study of the influence, still so inq^erfectly 

 known, of the molecular structure of bodies upon theii- relations to light, and 

 especially upon their transparency. 



Among the numerous works of Faraday relating to the applications of sci- 

 ence to the arts, we shall confine ourselves to citing his researches upon the 

 manufacture of steel, and of glass for optical purposes, these being the most 

 important. 



It was by the analysis of the Indian steel called ivoots that he was led, in 

 concert with Stodart, to compose an alloy which had all the properties of this, 

 by combining aluminium with iron and carbon. In a letter addressed in 1820 



