Chap. VIII.] Jgriculture. 97 



several others, who ?Jl formed the same eonchisions. 

 Still more recently the well devised and indubitable 

 experiments of Messrs. d'Ormoy, Rozier, Carmoy, 

 and Bartholon, all of France, have thrown addi- 

 tional light on the subject, and substantially con- 

 firmed the results of preceding experiments. 



The influence of various Factitious Airs in has- 

 tening and retarding the progress of vegetation is 

 a branch of agricultural inquiry peculiar to the 

 eighteenth century. On this subject the successive 

 experiments of Dr. Hales, Dr. Priestley, lord Dun- 

 donald, sir Francis Ford, and Dr. Darwin, of Great 

 Britain; of Ilassenfratz, and several other French 

 chemists ; and of Jacquin, von Uslar, and von 

 Humboldt, of Germany, have furnished very inte- 

 resting and important information. 



Beside the new substances employed for pro- 

 moting the fertility of soils, and hastening the pro- 

 cess of vegetation, the last age is also distinguished 

 by the introduction of a number of new and im- 

 portant objects of culture. 



Among these scarcely any is more worthy of at- 

 tention than the Potato. This valuable root, which 

 is generally supposed to have been found originally 

 m North America, was not much cultivated in 

 Europe till the close of the seventeenth century; 

 and even then was chiefly confined to Great Britain 

 and Ireland, and seldom seen except in gardens, 

 as a curioslt3^ How much it has increased in im- 

 portance, and in the extent of its cultivation, 

 since that period, both in America and in almost 

 every part of the civilised world, is well known. 

 Instead of being deemed, as it once '\^ as, a food 

 fit only for the lower classes of society, it has come 



VoL*I;. K 



