Chap. VIII.] AgrkiiUitrc, 95 



period, have made careful analysers of dlllerent 

 soils, and by this means tiirew much new lis^ht 

 on the principles of agj-icultnre. Tliose who most 

 flistinguished themselves by investigations of 

 this nature are Gio])ert5 Bero^man, Kirwan, and 

 Parmentier, to say nothing of several others, no 

 less worthy of being respectfully mentioned in thri 

 same list. 



The last century is also distinguished by llie in- 

 troduction of several new and' important Manures 

 into general use. Of these it will be proper to take 

 some notice in our rapid course. 



The great advantages of Gvpsiim as a manure 

 ^vere discovered in the 3^ear 17^^S, by ^Ir. Mayer, 

 a respectable German clergyman*. Since that time 

 this substance has been used wdth much success, 

 not only in Germany, but also in several otiiei' 

 parts of Europe, as well as in America; but the 

 manner in which it produces its fertilising effects, 

 notwithstanding the numerous and diligent inquiries 

 which have been made on the subject, is still far 

 from being satisfactorily unfolded. 



The eHicacy of Carbon, or common Charcoal, m 

 promoting vegetation, was first ascertained, a few 

 years a:<o, bv IVl. Ilassenfratz, a celebrated French 

 diemist. He found that this substance is an essen- 

 tial ingredient in the food of all vegetal,>les, and that 

 soils are, in general, fertile m proportion to the 

 quantity of it which they contain. The properties 

 and effects of car'oon as a manure have been since 

 'diligently ^.nd successfully examhied by Marion-; 

 other writers r\v\ experinrenters on tl^e subject. 



^' Trans'.iciiom of ihc P.oj/al Irisli Acairmy, vol. v, p. Ic}l5. 



