Liquid Manure, 



149 



now well ascertained that water is not the only food of plants, yet 

 it certainly contributes universally and largely to their support ; 

 and, as it has been well observed by Davy, no manure can be 

 taken up by the roots of plants unless water is present ; and water^ 

 or its elements, exists in all the products of vegetation.* 



It must not, however, be concluded that these carefully con- 

 sidered conclusions, from the results of often-repeated laborious 

 experiments, are erroneous, because transparent water, apparently 

 pure, as in water-glasses, or in irrigation, promotes the growth of 

 bulbs, grass, &c., since the very purest spring-water, even rain- 

 water, contains foreign substances, as I have clearly ascertained 

 by experiment ; and when only chemically pure water is employed 

 to water plants, they cannot be made to flourish. I have fruit- 

 lessly varied the attempt in several ways. All the experiments 

 of Dr. Thomson Avere equally unsuccessful, the plants vegetating 

 only for a certain time, and never perfecting their seeds. Similar 

 experiments were made by Hassenfratz and Saussure, and others, 

 with the same unfavourable result. Duhamel found that an oak 

 which he had raised from an acorn, in common water, made less 

 and less progress every year. The florist is well aware that bulb- 

 ous roots, such as hyacinths, tulips, &c., which are made to grow 

 in w^ater, unless they are planted in the earth every other year, at 

 first refuse to flower, and finally even to vegetate. Moreover, it has 

 been unanswerably shown by many very accurate experiments, f 

 at the varied repetition of which I have personally assisted, that 

 the quantity of nourishment or solid matters absorbed by the roots 

 of plants is always in proportion to the impurity of the water with 

 which they are nourished ; thus some beans were made to vegetate 

 under three different circumstances : the first were grown in dis- 

 tilled water ; the second were placed in sand and watered with 

 rain-water ; the third were sown in garden-mould. The plants 

 thus produced, when accurately analyzed, were found to yield the 

 following proportions of ashes : — 



1 . Those fed by distilled water • « 3.9 



2. Those fed by rain-water ■ [. • • 7.5 



3. Those grown in soil . . , 12.0 ' 



And again all attempts to make plants flourish in the pure earths 

 have failed utterly when they have been Avatered with pure water ; 

 yet a totally different result I have invariably experienced when I 

 have employed an impure solution or liquid manure. j\ly trials 

 have been entirely supported by those of ^I. Giobert, m Iio, having 

 formed of the four earths, silica, alumina, lime, and magnesia, a 

 soil in the most fertile proportion, in vain essayed to make the 



* Lecture 15. 



t Rech. sui- la Veg., 51. 



