INDUSTRIAL PROGRESS DURING THE YEAR 1874. x lix 



the point of 56, ordinarily given as the inferior limit for the 

 production of the octahedral form, is really only a tempera- 

 ture near the superior limit at which the prismatic form ap- 

 pears, the latter losing a part of its water at this temperature. 

 Basarow has investigated the compound of fluorine, oxygen, 

 boron, and hydrogen discovered by Gay Lussac and Thenard 

 in 1809, and called by them fluoxyboric acid, and has shown 

 that it has no separate existence, being only a solution of boric 

 acid in hydrofluoboric acid. Subsequently the same con- 

 clusion was reached for the salts. 



Melsens has succeeded in utilizing the absorptive power of 

 charcoal for gases for the purpose of liquefying them. Frag- 

 ments of recently calcined wood-charcoal are introduced into 

 the long leg of a Faraday tube; this is surrounded with ice, 

 and saturated with the gas to be liquefied. It is then hermet- 

 ically sealed, the longer leg is heated in a water-bath, the short- 

 er being in a freezing mixture. In this way sulphurous oxide, 

 chlorine, ethyl chloride, cyanogen, hydrogen sulphide, ammo- 

 nia, and hydrocyanic acid are liquefied with ease. Moreover, 

 he has observed that this charcoal, thus saturated with a gas, 

 exhibits marked active properties. Saturated with chlorine, it 

 burns hydrogen to hydrochloric acid even in the dark, produc- 

 ing a lowering of the temperature. Water in vapor is decom- 

 posed when passed over this chlorine-saturated charcoal, cold 

 and in the dark, producing hydrochloric and carbonic gases. 

 Liquids when used to moisten charcoal cause a considerable 

 rise of temperature ; in the case of bromine, using 11 grammes 

 of carbon and 97 of bromine, the elevation of temperature is 

 30 C. From this heat the calculated force of attraction of 

 the liquid for the solid surface is 893 atmospheres for water, 

 3080 for alcohol, 4620 for ether, 13,090 for carbon disulphide, 

 and 23,190 for bromine. Blochmann has made an exhaustive 

 research on the products of the incomplete combustion of 

 coal gas, and on the effects of heat upon coal gas. Godeffroy 

 proposes antimonous chloride as a test for caesium. In not 

 too dilute solutions of caesium, acidified with hydrochloric 

 acid, it throws down a white crystalline precipitate. This, dis- 

 solved in dilute hydrochloric acid, and evaporated, yields well- 

 formed hexagonal crystals permanent in the air. Crookes, the 

 discoverer of thallium, has published an extended paper on 

 this metal, giving its modes of occurrence, the methods of 



