WATERING. 



287 



to increase the quantity of these matters which 

 would so fall on this island, we may venture to 

 set the one against the other, and apply the 

 above statement to our own country, as the basis 

 of an estimate which singularly manifests the 

 ' power of littles,' as well as the grand scale on 

 which even the minutest of natural phenomena 

 proceed. Thus, on the Parisian data, the weights 

 of these fertilising materials, annually supplied 

 to the soil of this island by the rain, amount to 

 about 



400,000 tons of ammonia. 

 1,850,000 — nitric acid. 



279,000 — chlorine. 



640,000 — lime. 



244,000 — magnesia." 

 It is probable no other water in a natural 

 state contains so great an amount of fertilising 

 matter; and it is quite certain that the waters 

 of many springs, should they peradventure con- 

 tain no material injurious to vegetation, contain 

 little or no matter which can properly be called 

 the food of plants. It therefore is a matter of 

 the deepest importance to the horticulturist to 

 endeavour to secure rain water ; and this is by 

 no means so difficult a matter, if properly gone 

 about.— (Vide sect. Tanks, &c.) Next to rain 

 water is that which is, by chemical analysis, 

 proved to contain the largest portions of the 

 above constituents, and the least amount of 

 those matters which are either useless or inju- 

 rious to vegetation , Those who have to depend 

 on springs for their supply of water for garden 

 purposes, had need ascertain the chemical pro- 

 perties of them before going to the expense of 

 forming wells, pumping the water up, or bring- 

 ing it from a distance ; for as the water may be 

 deficient in the above matters, so is their labour 

 in vain, and the expense incurred next to thrown 

 away. Plants require something more than 

 pure water. It is the quality and not the quan- 

 tity of water that is beneficial to them. Some 

 interesting experiments have recently been made 

 by Chevandier and Salvetat, to solve the pro- 

 blem, whether it is the quantity of water ap- 

 plied or put in motion, or the presence of matter 

 held in solution — which water, acting as a vehicle, 

 conveys to the roots of plants — that is of great- 

 est benefit to them. In carrying out their ex- 

 periments, the water of two different springs was 

 made use of, which, for clearness, we shall call 

 No. 1 and No. 2. 255,744 cubic metres of water, 



No. 1, was applied per hectare, and 164,281 

 cubic metres from No. 2, to the same extent of 

 surface. The produce in the first case was 2312 

 kilogrammes per hectare, while in the other it 

 was 7896 kilogrammes. The second year's experi- 

 ments produced the following results.: 126,273 

 cubic metres were applied per hectare from spring 

 No. 1 ; the weight of crop produced was 2749 

 kilogrammes. 130,311 cubic metres from No. 2 

 produced, in weight of crop, 10,469 kilogrammes. 

 " We thus see," say these gentlemen, " that with 

 equal quantities of water, and in conditions in 

 other respects perfectly comparable, or even 

 with larger quantities of water from the bad 

 spring (No. 1), the crop of the meadow watered 

 by this spring has only been one-third or one- 

 fourth of the crop produced under the influence 

 of the water from the good spring (No. 2). It 

 is then in the quality of the waters, and not in 

 their quantity, that we should seek for the 

 causes of these very considerable differences in 

 the crops." 



The gases and organic matters held in suspen- 

 sion in both these springs were nearly the same. 

 Messrs Chevandier and Salvetat therefore sought 

 the solution of the problem in the organic mat- 

 ters dissolved in these waters. According to the 

 centesimal composition of these matters in the 

 springs No. 1 and No. 2, taken as types in this 

 extract, oxygen and hydrogen were found in the 

 same proportion ; but these matters were more 

 rich in carbon in spring No. 1 , and more rich in 

 nitrogen in spring No. 2. The nitrogen in No. 

 2 was to that of No. 1 as 100 to 42, whilst the 

 carbon in No. 2 was to that of No. 1 as 100 to 

 94. The two propositions here laid down do 

 not sufficiently explain the different fertilising 

 powers ; but the following will do so : " If in- 

 stead," say these gentlemen, " of considering 

 merely the absolute quantities, either of organic 

 matters or of nitrogen contained in these mat- 

 ters, we seek the relative proportions of the 

 nitrogen and carbon which enter into their com- 

 position, we find that 100 of carbon correspond 

 in the good spring to at least 11 of nitrogen, 

 and, for the bad spring, to 4 of nitrogen at the 

 most ; whence we see, that the fertilising pro- 

 perties of our good springs correspond com- 

 pletely to a proportion three times stronger, 

 considered relatively to the carbon." — (Vide The 

 Chemist, and Cumptes Rendus of Feb. 1852.) 



