184 THE 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. 



LETTER XLI. 



TO THE SAME. 



Selborne, July 3, 1778. 



Dear Sir, 



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 



1 [Even in White's day the importance of a scientific knowledge of grasses had 

 been recognised. Gahn published in the Amcenitates Academicce (1767), under the 

 direction of Linnaeus, an account of the common grasses, with mention of the writers 

 who had studied the order. The subject has since received much attention.] 



