iv The Preface. 
As the art ofThyfick has of late years been 
much improved by a greater knowledge of the 
animal economy $ fo doubt lefs a farther infight 
into the vegetable ceconomy muft needs pro- 
portionably improve our skill in Agriculture 
and Gardening , which gives me reafon to 
hope , that inquiries of this kind will be ac- 
ceptable to many , who are intent upon impro- 
ving thofe innocent , delightful, and beneficial 
Arts: Since they cannot be infenfible that 
the moft rational ground for Succefs in this 
laudable purfuit muft arifefrom a greater in~ 
fight into the nature of Tlants. 
Finding by many Experiments in the fifth 
chapter, that the Air is plentifully infpired 
by Vegetables, not only at their roots , but 
alfo thro fever al parts of their Trunks and 
Branches > this put me upon making a more 
particular inquiry into the nature of the Air $ 
and to dif cover, if pojfible, wherein its great 
importance to the life and fupport of Vege- 
tables might confift 5 on which account I was 
obliged to delay the publication of the reft of 
thefe Experiments , which were read two 
years fince before the Royal Society, till I 
had made fame progrefs in this inquiry . An 
account of which I have given in the fixth 
chapter . 
Where 
