10 -CONCERNING SZCT.IU 



The natural ftate of water uninfluenced by heat is 

 ice, and where very cold, it is too denCe a fluid to pafs 

 through forae of the capillary veflels of plants; yet a 

 fmall degree of heat rarifies it; and as its -globules are 

 capable x)f being infinitely divided by a proportionate 

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

 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 relpeft alone, it is molt va- 

 luable. Without it, nothing could be elaborated in 

 nature, no fermentation be wrought, and animals and 

 plants would die of thirft ! 



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AlR is found in a confiderable degree in water, in 

 plants, and in fruits. It may be almoft demonftrated 

 (fays one) that the vegetable nourishment 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 

 common eft observation 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- 

 riih in a free and open air, and grow pale and languifh 

 in the contrary. But air is not only ^neceffary 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 houfed plants has been laid to be 

 ©wing greatly to want of motion. But the want of 

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

 is fraught with animating principles, and by ^attenua- 

 ting and elaftic properties, feparates the grofsjuices 3 

 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 refreflied by them. 



