60 On the Use of Green Vitriol of Iron, 



tions relative to the preceding memoir, which seem worthy 

 of notice. 



'' Ashes of wood contain vtrv commonly sulphate of 

 potash, also phosphoric acid, besides otlier well known 

 salts ; but after these salts are separated by lixiviation, there 

 remains a peculiar earth and a small proportion of iron. 

 This earth diflers from lime, baryt, magnesia, strontian, or 

 any other known species of earth. I would call it cinis, for 

 plentiful, common, and important as it is, science has not 

 dignified it with a name. To judge of the excellence of 

 this earth as a manure, after all the salts are extracted from 

 soap-boilers' ashes, the earth sells for ten cents the bushel ; 

 and, notwithstanding this high price, it is not unusual for 

 the farmer to pay for the article twelve months beforehand. 

 When ploughed into steril ground, at twelve loads per 

 acre, it produces great crops of wheat, clover, and other 

 sorts of grass and grain, and its fertilizing operation will 

 last twenty years. Although some of the other ingredients 

 of the ashes left after lixiviation may prove beneficial, yet 

 the effects are chiefly from the cinis, or new named earth. 



^' This earth, which is so prized in America as a manure, 

 was esteemed of old in Asia as an ingredient in a cement : 

 Among the anticnt Syrians it was one of the materials form- 

 \n^ the plaster of their walls ; and, as it holds an interme- 

 diate place between lime and potash, it can easily be con- 

 ceived how it may act both as a cement and a manure. It 

 Js to be hoptd chemists will turn their attention to this im- 

 portant subicct." (Sec Tilloch's Philosophical Magazine, 

 vol. vii. p. '-'73, for the whole of this interesting letter.) 



J, Several metallic Salts promote Vegetation, shoini bj the 

 Experiments of Professor Barton, of Pkiladefpltia. 



Letter from Ben J ami. v Smith Bartox, M. D. Professor 

 of Medicine in the College of Philadelpliia, to Dr. Pear- 

 son, containing Experiments uith vietallio Sohutions to 

 determine their Effects on Plants, 



sin, Philadelpliia, Oct 2S, 1F02. 



In the Jnnals of Medicine for tlie year ] 801, you inform 

 lis that vou hive lately read a paper at the Board of Agri- 

 culture " containing an account of the effects of a saline 

 body collected from peat as a most pow erful manure, which 

 turns out to be sulphate of iron ; a substance, you. remark, 

 hitherto considered to be a poison to plants." This piee?^ 

 of intelligence gave me much satisfaction. I have, for some 

 yca^rsj been engaged in an extensive series of experiments 



relative 



