98 THE CANADIAN NATURALIST. [A-pril, 



soil ; but the manures termed " artificial," which have theirorigin 

 elsewhere than in the farm itself, and are for the most part of 

 concentrated and portable character, have but of late years come 

 largely into use. Nevertheless the manufacture of these manures, 

 and the trade to wliic!i they have given rise, already rank amongst 

 the most extensive of modern industries. 



[The author here gives a brief history of the various processes 

 proposed and patented in England for the preparation of artificial 

 manures during the first third of this century. They were but 

 three in number, of which two were for the utilization of night-soil, 

 while a third proposed the use of a mixture of oyster-shells and 

 gypsum. In the course of the eighteenth century three patents for 

 manure were obtained, one of which described a mixture of sea-salt, 

 saltpetre, lime, and Rhenish tartar, declared to " possess a mag- 

 netic quality whereby it attracts fertility, etc."] 



Course of Early Scientific Research. — In the mean 

 time, however, a vast store of scientific information, tending more 

 or less directly to the elucidation of this important subject, had 

 been in slow and silent course of accumulation, by the successive 

 labors of many eminent experimentalists. 



Not to go bick farther than the last century, nor even than its 

 latter half, we shall find concentrated in this brief period, a series 

 of brilliant discoveries, bearing more or less directly upon the 

 manurial and agricultural questions, but far too numerous even 

 for the most cursory narration here. Space would fail us even ta 

 enumerate the names of European celebrity that adorned this 

 memorable epoch ; but if we had to select half a dozen of the most 

 illustrious to represent the philosophical activity, British and con- 

 tinental, of the p3riod, we would venture to single out on the one 

 hand. Black, Priestley, and Cavendish — and on the other, 

 Lavoisier, De Saussure, and Berthollet. 



Daring the fifty years in question the nature and composition 

 of ail' and water, o^ carbonic acid and ammonia^ (the four main 

 forms of volatile plant-food,) were discovered,their gaseous elements 

 isolated, and their properties determined. 



The sciences of geology and meteorology at this period alsa 

 began to take shape and form; enabling an insight to be gained 

 into the ori2:in and natare of cultivable soils, and into the climatic 

 conditions of plant-growth. 



At the same time the laws of the physical forces, particularly 



