ONE HUNDEED YEAES OF CHEMISTEY 331 



lished in 1868, gave an excellent account of the principles 

 of agricultural chemistry. He did much to bring about 

 the establishment of agricultural experiment stations in 

 this country, and for a long time he was the director of 

 the Connecticut Station. 



In the Journal, as early as 1827, Amos Eaton (12, 370) 

 published a simple method for the mechanical analysis 

 of soils to determine their suitability for wheat-culture, 

 and Hilgard, between 1872 and 1874, described an elab- 

 orate study of soil-analysis. J. P. Norton, a Yale 

 professor, in 1847 (3, 322) published an investigation 

 on the analysis of the oat, which was awarded a prize of 

 fifty sovereigns by a Scotch agricultural society, while 

 Johnson, Atwater, and others have contributed articles 

 on the analysis of various farm products. 



Industrial Acids and Alkalies. 



One hundred years ago sulphuric acid was manufac- 

 tured on a comparatively very small scale in lead 

 chambers. In 1818, an English manufacturer of the 

 acid introduced the modern feature of using pyrites in 

 the place of brimstone, while the Gay-Lussac tower in 

 1827 and the Glover tower in 1859 began to be applied as 

 great improvements in the chamber process. Within 

 about twenty years the contact process, employing plat- 

 inized asbestos, has replaced the old chamber process to 

 a large extent. It has the advantage of producing the 

 concentrated acid, or the fuming acid, directly. 



During our period the manufacture of sulphuric acid 

 has increased enormously. Very large quantities of it 

 have been used in connection with the Leblanc soda pro- 

 cess in its rapid development. It came to be employed 

 extensively for absorbing ammonia in the illuminating- 

 gas industry, which was in its infancy one hundred years 

 ago. New industries such as the manufacture of "super- 

 phosphates" as artificial fertilizers, the refining of petro- 

 leum, the manufacture of artificial dyestuffs and many 

 other modern chemical products have greatly increased 

 the demand for it, while its employment in the production 

 of nitric and other acids, and for many other purposes 

 not already mentioned, has been very great. 



The manufacture of nitric acid has been greatly 



