JO CONCERNING SZCT. II. 



The natural ftate of water uninfluenced by heat is 

 ice, and when very cold, it is too deivfe a fluid to pais 

 through fome of the capillary vcflels of plants; yet a 

 irnall degree of heat rarifies it ; and as its globules arc 

 capable of being infinitely divided by a proportionate 

 heat ; it is thus rendered fit to pafs through the fined 

 canals. It mixes with the nutritive properties that are 

 lodged in the earth, and is (at leaftj the vehicle of the 

 food of plants. In this reipecl: alone, it is moil va- 

 luable. Without it, nothing could be elaborated in 

 nature, no fermentation he wrought, and animals and 

 plants would die of thirft ! 



AlR is found in a confiderable degree in water, m 

 •plaiUs, and in fruits. It may be almoft demonftrate^ 

 (fays one) that the vegetable nourimment is princi- 

 pally in the air : The tree Sedum fufpended, lives and 

 grows for years by air and its moifture. 



How necejjary this element of air is to man, the 

 commoner!: obfervation evinces. Deprived of air, life 

 is quickly loft, and in a depraved ftate of it, runs faft 

 to ficknefs and death. Thus plants are found to flou- 

 rifh in a free and open air, and grow pale and languid 

 in the contrary. But air is not only neceflary for the 

 leaves of plants to breathe in, but their roots require it : 

 Plants will not do well if the foil is too much bound 

 for the air to penetrate freely about them. 



The ficklinefs of houjed plants has been faid to be 

 owing greatly to want of motion. But the want of 

 freih air, is undoubtedly the chief caufe ; for pure air 

 is fraught with animating principles, and by its attenua- 

 ting and elaftic properties, feparates the grofs juices, 

 keeps the fap in motion, and the plants in health. 



Air conveys to the organs of fmelling, all thofe grate- 

 ful fcents, which plants, flowers and fruits produce, 

 and we are greatly regaled, and refreihed by them* 



