256 PROGRESS IN CHEMISTRY. 



that the iinahsorba])lo residue possessed an unknown spectrum, and 

 that its density was nearh' 20. To this new gas they gave the name 

 "argon," or inactive, seeiijg that all attempts to cause it to enter into 

 combination had failed. In 1895 Ramsay, searching for possi])le com- 

 binations of argon in minerals, experimented with one which had been 

 previously examined by Hillebrand. of Baltimore, and obtained from 

 it helium, a gas of density '2, possessing a spectrum which had bi'en 

 previously discovered in 1868 in the chromosphere of the sun ))v fbmn- 

 sen, of Paris, and named helium by Frankland and Lock^er. Subse- 

 quent liquefaction of crude argon l)v means of liquid air. prepared In' 

 a process invented simultaneoush' by Linde and Hampson, gave a res- 

 idue which was named bj" its discoverers, Ramsay and Travers, " neon." 

 Liquid argon has yielded two other gases also, ''krypon ""and '•xenon.'' 

 These elements form a separate group in the Periodic Table, com- 

 mencing with helium, with atomic weight 1: neon. 20: argon, 1:0; 

 krypon, 82, and xenon, 128. They all agree in being monoatomic; 

 i. e., their molecules consist of single atoms, and they have no ten- 

 denc}' to form compounds; i. e., they possess no valencv. 



CHEMISTRY AND COMMERCIAL SUPREMACY. 



In this sketch of the progress of chemistry during the century which 

 has just passed attention has been paid chiefly to the progress of thought. 

 Allusions must, however, be made to the applications of chemistry to 

 industrial purposes. The development of the soda industry, the prep- 

 aration of carbonate of soda and caustic from common salt — initiated 

 in France by I.e Blanc (1742-1806) — has been developed by Tennant in 

 Scotland, and ]Muspeath and Gossage, and by Hargreaves, Weldon. and 

 Maetea in England. This process has at present a serious rival in the 

 ammonia-soda process developed by Solwaj" in Belgium and by Brun- 

 ner and Mond in England. The manufacture of sulphuric acid, so 

 long associated with the alkali process, has made enormous strides 

 during the present century, but is still, in the main, the original proc- 

 ess of causing sulphur dioxide in presence of water to absorb the 

 oxygen of the air through nitric oxide. But the saving of the oxides 

 of nitrogen through the invention of a sulphuric-acid tower by Gay- 

 Lussac, known by his name, and the reutilization of these oxides in 

 the "Glover" tower, invented by John Glover, of Newcastle, have 

 greatl}' lessened the cost of the acid. Concentration of the acid in 

 iron vessels is now common, the cost of platinum or of fragile glass 

 vessels being thereb}^ saved. The desulphurization of iron and the 

 removal of silicon, carbon, and phosphorus b}- Bessemer's process, 

 modified by Thomas and Gilchrist through the introduction of a "" basic 

 magnesia lining" for the converters, has made it possil)le to obtain 

 pure iron and steel from ores previously regarded as of little value. 



