216 NATURAL HISTORY 



The productions of vegetation have had a vast influence on 

 the commerce of nations, and have been the great promoters 

 of navigation, as may be seen in the articles of sugar, tea, 

 tobacco, opium, ginseng, betel, paper, &c. As every climate 

 has its peculiar produce, our natural wants bring on a mutual 

 intercourse; so that by means of trade each distant part is 

 supplied with the growth of every latitude. But, without the 

 knowledge of plants and their culture, we must have been 

 content with our hips and haws, without enjoying the delicate 

 fruits of India and the salutiferous drugs of Peru. 



Instead of examining the minute distinctions of every 

 various species of each obscure genus, the botanist should 

 endeavour to make himself acquainted with those that are 

 useful. You shall see a man readily ascertain every herb of 

 the field, yet hardly know wheat from barley, or at least one 

 sort of wheat or barley from another. 



But of all sorts of vegetation the grasses seem to be most 

 neglected ; neither the farmer nor the grazier seem to distin- 

 guish the annual from the perennial, the hardy from the 

 tender, nor the succulent and nutritive from the dry and 

 juiceless. 



The study of grasses would be of great consequence to a 

 northerly, and grazing kingdom. The botanist that could im- 

 prove the swerd of the district where he lived would be an 

 useful member of society: to raise a thick turf on a naked soil 

 would be worth volumes of systematic knowledge ; and he 

 would be the best commonwealth's man that could occasion 

 the growth of " two blades of grass where one alone was seen 

 before." 



I am, &c. 



