[ xvi ] 

 learned Body, the annual prize me- 

 dal upon Dr. Prieftley, decreed to 

 him as an honourable teftimony of 

 their approbation of the fuccefsful 

 labours bellowed by him upon the 

 doctrine of air. " From thefe difco- 

 veries," fays he, " we are allured, 

 that no vegetable grows in vain, 

 but that, from the oak of the foreft 

 to the grafs in the field, every in- 

 dividual plant is ferviceable to 

 mankind ; if not always diftin- 

 guifhed by fome private virtue, 

 yet making a part of the whole, 

 which cleanfes and purifies our 

 atmofphere. In this the fragrant 

 rofe and deadly night-made co- 

 operate: nor is the herbage, nor 

 the woods that flourim in the 

 moft remote and unpeopled re- 

 gions, unprofitable to us, nor we 

 to them; confidering how con- 



" ftantlv 



