170 YEAR-BOOK OF FACTS. 



distillation of coal-tar, but now manufactured by the hundredweight 

 in consequence of the extensive demand for the beautiful colours 

 known as Mauve, Magenta, and Solferino, which are prepared by 

 the action of oxidizing agents, such as bichromate of potash, corrosive 

 sublimate, and iodide of mercury upon aniline. 



"Nor has the inorganic department of chemistry been depi-ived of 

 its due share of important advances. Schonbein has continued 

 his investigations upon ozone, and has added many new facts to our 

 .knowledge of this interesting substance ; and Andrews and T:\it, by 

 their elaborate investigations, have shown that ozone, whether 

 admitted to be an allotropic modification of oxygen or not, is cer- 

 tainly much more dense than oxygen in its ordinary condition. 



"In Metallurgy we may point to the investigations of Deville 

 upon the platinum group of metals, which are especially worthy of 

 remark on account of the practical manner in which he has turned to 

 account the resources of the oxy-hydrogen blowpipe, as an agent 

 which must soon be very generally adopted for the finer description 

 of metallurgic operations at high temperatures. By using lime as 

 the material of his crucibles, and as the support for the raetals upon 

 ■which he is operating, several very important practical advantages 

 have been obtained. The material is sufficiently infusible to resist 

 the intense heat employed ; it is a sufficiently bad conductor of heat 

 to economize very perfectly the high temperature which is generated ; 

 and it may be had sufficiently free from foreign admixture to pre- 

 vent it from contaminating the metals upon which the operator is 

 employed." 



LIQUEFACTION OF GASES. 



MM. Lorn and Drion have described in the Bulletin de la 

 Socicte Chimique, a method by which many of the Gases may be 

 Licpuefied in considerable quantities. It depends on the cold pro- 

 duced by the evaporation of volatile liquids, which was first used 

 by M. Bussy in the liquefaction of ammoniacal gas. 



In describing the liquefaction of a gas, authors have generally 

 contented themselves with saying that it could be effected by a 

 certain freezing mixture, which in many cases has a lower tem- 

 peraturo than is absolutely necessary. Hence the liquefaction of 

 gases is generally thought to be a more difficult operation than 

 really is the case. 



By blowing a dried current of air by means of a blowpipe bellows, 

 through several tubes into about 7 ounces of ether, a temp irature of 



— 34° C. can be obtained: this temperature, which is reached in 

 about four to five minutes, and can be kept pretty constant for 

 fifteen to twenty minutes, is more than sufficient to liquefy a con- 

 siderable quantity of cyanogen gas. By regulating the rapidity of 

 the air-current, it was found that the temperature of liquefaction IB 



— 22°. By blowing slightly through an ordinary pair of bellows 

 over the surface of the liquid gas it solidifies immediately. 



By a similar arrangement a large quantity of suljihurous acid may 

 be liquefied. 



