BOTAST OP SELBOETTE. 239 



The productions of vegetation have had a vast influence 

 on the commerce of nations, and have been the great pro- 

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

 tea, tobacco, opium, ginseng, betel, pepper, &c. As every 

 eKmate has its peculiar produce, our natural wants bring 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 sh'oula 

 endeavour to make himself acquainted with those that are 

 useful. Tou 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 jidceless. 



The study of grasses would be of great consequence to a 

 northerly and grazing kingdom. The botanist that could 

 improve the sward 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 occa- 

 sion the growth of " two blades of grass where one alone 

 was seen before." 



LETTEE LXXXIII. 



TO THE SAME. 



Seibohne, July 3, 1778. 

 Deae Sie, — In a district so diversified with such a variety 

 of hill and dale, aspects and soils, it is no wonder that great 

 choice of plants should be found. Chalks, clays, sands, 

 sheep-walks and downs, bogs, heaths, woodlands, and cham- 



