28 Review of ChaptaVs Chemistry of ^Agriculture. 



difficulty with which water penetrates them, and the little tendency they 

 have to ferment. 



" A very good manure is likewise formed from wool. According to 

 the ingenious experiments of M. Hatchett, hair, leathers, and wool are 

 only particular combinations of gelatine with a substance analogous to 

 albumen ; water can only dissolve them by means of fernieutation, 

 which lakes place slowly, and after a long time. 



" One of the most surprising instances of fertile vegetation that I have 

 ever seen, is that of a field in the neighborhood of Montpelier, belonging 

 to a manufacturer of woollen blankets. The owner of this land causes 

 it to be dressed every year with the sweepings of his workshops ; and 

 and the harvests of corn and fodder which it produces are astonishing. 



" It is well known that the hairs of wool transpire a fluid which 

 hardens upon their surface, but which possesses the property of being 

 easily soluble in water. This substance has received the name of animal 

 sweat ; the water in which wool has been washed contains so much of it, 

 as to make it very valuable as a manure. 



" A wool merchant in Montpelier, placed his wash-house for avooI in 

 the midst of a field, a great part of which he had transformed into a 

 garden. In watering his vegetables, he had used no other water than 

 that of the washings ; and the beauty of his productions was so 

 great, as to render his garden a place of general resort. The Genoese 

 collect with care, in the south of France, all they can find of shreds and 

 rags of woollen fabrics, to place at the foot of their olive trees." 



" In the south of France, where they raise many silk-worms, they make 

 make great use of the larvas, after the silk has been spun from cocoons. 

 They are spread at the foot of the mulberry and other trees, of which 

 the vegetation is in a languishing condition ; and this small quantity of 

 manure reanimates them surprisingly. Upon distilling some of these 

 larvas, I found more ammonia than i have ever met with in any other 

 animal matter." 



The supposed phenomenon of the reappearance of seeds 

 in lands very many years after sown, and hence the absurd 

 theories of spontaneous generation, and the like, are thus 

 overthrown by the true state of the vegetable vitality. 



" Germination cannot well be carried on, unless the atmospheric air 

 has access to the seed, which cannot be the case if the seed be buried too 

 deeply in the ground, or if it be sown in a compact soil and closely cov- 

 ered over. 



" It likewise follows, from these principles, that when the earth re- 

 mains a long time covered with standing water, the seeds must decay, 

 and also, that a seed placed in dry earth cannot germinate unless it be 

 moistened. 



" The impossibility of a seed's germinating, when too deeply buried 

 in the ground, explains why we sometimes see, after deep tilling, plants 

 making their appearance, of the same kind as those which had been 

 cultivated upon the soil several years before. The state of the earth, 

 as it regards moisture, at the time of sowing, furnishes a reason inde- 

 pendent of the action of heat, why seeds are a longer or shorter time in 

 sprouting." 



Influence of carbonic acid on vegetation: 



"The pieces of wood which support the roof of the long gallery which 

 conducts to the beds of coal in the coal mines of Bousquet, in the de- 

 partment of Beziers, were loaded with that species of mushroom which 

 usually fixes itself upon the trunks of old trees ; the entrance of the 

 gallery is very light, but the light gradually diminishes till it is lost in 



