I 
258 SOILS, MANURES, &c. 
Oils are of various qualities ; all ani¬ 
mal and vegetable oils are great promoters 
of vegetation, they are infoluble in water, 
without the mediation of alkaline falts, 
and but imperfedtly fo without the fal- 
faponarius. 
Animal and vegetable fubflances have 
a near affinity to each other, as appears 
by their reciprocal commutations. 
Animals derive their fuftenance from 
vegetables, either immediately or ulti¬ 
mately, and when decompofed by putre- 
faflion, they become great promoters of 
vegetation. 
Nightly dews are of the utmoft con- 
fequence to vegetation, efpecially in hot 
climates, where they are probably the 
vehicles which convey the fovereign, 
nitrous, or aerial acid, more direftly to 
plants and to foils, and in greater quan¬ 
tity than they could otherwife poffibly 
obtain 
