[ xxvii ] 



f l againft a hundred cafes, in which 

 " the air is made worfe by it. 5 ' 



Soon after, p. 305, he relates 

 feveral inftances in which a plant 

 had, in the ipace of feven, eight, 

 ten, or more days, effectually mend- 

 ed the foul air in which it was 

 made to grow. P. 309, he relates 

 a fact, in which a fprig of winter 

 favory, kept growing in a jar from 

 the 1 6th of June to the 20th, had 

 improved the air evidently, which 

 improvement he found by three re- 

 peated trials to be in the proportion 

 of 1.275 to 1.375. He relates 

 another inifance, in which air was 

 fo much improved by a fprig of 

 parfley growing in if, from the 1 6th 

 of June to the 1 it of July, that one 

 meafure of it with one of nitrous 

 air occupied only one meafure. 



