LIQUID MANURE. 



over 3 or 4 times in this period), is fully equal, 

 if not superior, to any thus recommended, 

 most of which I have tried. When mixed 

 with water and spread over land intended for 

 wheat, at the rate of from 25 to 35 bushels of 

 the salt and lime to 10 or 15 tons of water per 

 acre (and it answers very nearly as well when 

 carried on the land dry), excellent results are 

 produced. The wheat which I have thus 

 grown on clover leys has been superior in 

 height, and strength of straw, to any I have 

 seen produced under different modes of treat- 

 ment, and the seed very bright and heavy. 



All substances, whether organic, earthy, or 

 saline, which are employed to fertilize the soil, 

 or become the food of plants, can only be ren- 

 dered thus serviceable to vegetation when they 

 are presented to the roots of plants in solution, 

 or in a fluid state ; and although this may 

 appear at first rather a sweeping position, yet 

 such is the real fact, the compost of the farm- 

 yard, the crushed bones of the turnip cultiva- 

 tor, the oil and bones of fish, the gypsum of 

 the grazier, the earths, lime, magnesia, and 

 even silica, and ail the saline manures, are 

 dissolved by some process or other before they 

 can be absorbed by vegetables. Every attempt 

 which has been hitherto made to make plants 

 imbibe the most minutely divided powders which 

 chemistry can produce, has been entirely fruit- 

 less. Davy ineffectually tried the finest im- 

 palpable powder of charcoal, and with much 

 perseverance I have fruitlessly employed the 

 earths, saline substances, and organic matters, 

 for the same purpose. 



This absolute necessity for every substance 

 which is the food of plants being of a soluble 

 nature did not escape the sagacity of the early 

 Greek and Egyptian philosophers; it is true 

 they carried their conclusions with regard to 

 subjects of natural philosophy too far, as in 

 this instance, when they asserted that water is 

 the only food of plants ; yet they must have 

 patiently noticed many facts in vegetable eco- 

 nomy, unaided as they were by the light of mo- 

 dern vegetable chemistry, before they could 

 have arrived at a conclusion so nearly ap- 

 proaching the truth. The idea was probably 

 of Egyptian origin, for the cultivators of that 

 country could not fail to notice the magic fer- 

 tilizing powers of the waters of the Nile, whose 

 annual overflow is perhaps the most extensive 

 natural irrigation taken advantage of by the 

 cultivators of the earth. 



The same wild dream of water being the sole 

 food of vegetables was again revived, so lately 

 as 16 10, by M. Van Helmont, a celebrated Dutch 

 chemist, who made some very plausible, de- 

 ceptive experiments on a willow tree, which 

 he watered only with rain water; researches, 

 however, whose inaccuracy (owing principally 

 to rain water, as usually collected, not being 

 quite pure) was shown in 1691 by Mr. Wood- 

 ward. Although, therefore, it is now well as- 

 certained 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 pre- 

 gent ; and water, or its elements, exists in all 

 fhe products of vegetation. (Lecture 15.) 

 728 



LIQUID MANURE. 



It must not, however, be concluded that these 

 carefully considered conclusions, from the re- 

 sults of often-repeated laborious experiments, 

 are erroneous, because transparent water, ap- 

 parently pure, as in water-glasses, or in irri- 

 gation, 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 fruitlessly varied the attempt in several 

 ways. All the experiments of Dr. Thomson 

 were equally unsuccessful, the plants vegetat- 

 ing only for a certain time, and never perfect- 

 ing 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 bulbous roots, such as hyacinths, tulips, 

 &c., which are made to grow in water, 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 

 (Rech. sur la Veg. p. 51), at the varied repetition 

 of which I have personally assisted, that the 

 quantity of nourishment or solid matters ab- 

 sorbed by the roots of plants is always in pro- 

 portion to the impurity of the water with which 

 they are nourished; thus some beans were 

 made to vegetate under three different circum- 

 stances ; the first were grown in distilled water; 

 the second were placed in sand and watered 

 with rain water; the third were sown in gar- 

 den mould. The plants thus produced, when 

 accurately analysed, 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 flour- 

 ish in the pure earths have failed utterly when 

 they have been watered with pure water; yet 

 a totally different result I have invariably ex- 

 perienced when I have employed an impure 

 solution or liquid manure. My trials have 

 been entirely supported by those of M. Giobert, 

 who, having formed of the four earths, silica, 

 alumina, lime, and magnesia, a soil in the 

 most fertile proportion, in vain essayed to 

 make the plants flourish in it when watered 

 with pure water only; but every difficulty was 

 removed when he moistened it with the water 

 from a dunghill, for they then grew most luxu- 

 riantly; and M. Lampadius still further de- 

 monstrated the powers of such a foul liquid 

 manure, for he formed plots composed of only 

 a single earth, pure lime, pure alumina, pure 

 silica, and planted in each different vegetables, 

 watering them with the liquid drainings from 

 a dunghill, and he found that they all flourish- 

 ed equally well. The soluble matters of a soil 

 ever constitute, in fact, its most fertilizing por- 

 tion ; and if by any artificial means the richest 

 mould is deprived of these, as by repeated 

 washings in cold or boiling water, the re- 

 siduum, or remaining solid matter, is rendered 

 nearly sterile : this fact, first accurately demon- 



