330 



THE FARMER'S MAGAZINE. 



form such large quantities of ammonia, phosphates, &c., 

 as to equal the value of ^35 per acre, in one year, from 

 a bulk of water containing ^83*8 worth ? I answer, 

 that certainly very good effects have been produced by 

 water ; but that it has been proved that those waters 

 had matters in suspension, or solution, of great value to 

 the lands over which they passed. But I never heard 

 of such great results from water-meadows as from those 

 at Edinburgh. But to discover whether soil can take 

 up fully the amazing amounts stated, let us examine a 

 little further the experiments of Dr. Voelcker. His 

 mixture contained in a gallon 35.58 grains of ammonia, 

 besides potash, phosphoric acid, &c,, and an amount of 

 soil in the proportion of only one part in weight of soil 

 to 32 parts weight of liquid : namely, 2,000 grains of the 

 soil to 7,000 grains of the liquid mixed together, and 

 the soil retained 14.75 out of the 35.58 grains. To 

 see how this fact stood in the matter of bulk as well as 

 weight, and how much would have been retained in an 

 acre of land, I had some ground carefully cut out from 

 grass-land, to the depth of a foot, taken up and weighed. 

 Excluding a quarter of an inch at the top (where the 

 grass was), it weighed at the rate of 112 lbs. per cubic 

 foot. I had it dried for two days, at a heat above boil- 

 ing water, till it lost no more in weight, and I found 

 that it had been reduced in weight to 86.2 lbs. JVIulti- 

 ply 86.2 lbs. by 3J, and the result will be the weight 

 of liquid-manure to put to it to equal Dr. Voelcker's 

 experiment, the result will be 301 lbs. of liquid 

 to 86.2 lbs. of soil, or to every foot of surface of land 

 if the land is to be drenched to one foot deep. But I 

 shall only consider that the top soil is the amount of 

 soil that takes up the fertilizers from the liquid- manure ; 

 and if I consider this to be ten inches deep (if I 

 take it deeper the argument is stronger in my favour), 

 it will be seen that in round numbers one ton 

 of liquid would be the quantity to each yard of 

 surface; or, as there are 4,840 square yards to an acre, 

 4,840 tons of liquid would impart to an acre of land 

 as large a proportion of ammonia, &c., as the 7,000 

 grains of liquid did to 2,000 grains of soil. 



Without further detailing the calculation, it will be 

 found that this amount of liquid would contain a value 

 (at 35.6 grains to a gallon, and at 6d. per lb. for the 

 ammonia, putting nothing down for the value of the 

 phosphates, &c.) of ^130 ; and the acre of land would 

 retain (according to Dr. Voelcker's experiment, where 

 14.77 grains was extracted from the gallon) ^55's 

 worth of ammonia, besides other fertilizers. And this 

 £bb'& worth of manure per acre is extracted in the one 

 dosing from i,130's worth in the liquid, in the space of 

 time (whatever that is) that this quantity would have taken 

 to pass through the soil. " Is this the utmost amount 

 that the soil can hold at one time?" — Dr. Voelcker 



asks this question ; but says that, at present, it cannot 

 be answered. Would vegetation assimilate these fer- 

 tilizers ? Could another, or several more doses equal 

 to this one, be given periodically, so that the acre of 

 land should take up a yet larger quantity in the course 

 of the year? Very likely the plants could not bear 

 such large quantities of a liquid-manure of this strength ; 

 for the manure contains 6id. worth of ammonia, besides 

 other matters, in the ton, while the Edmburgh sewage 

 has an amount of manuring matter in it oi which am- 

 monia, together with all other matters, is worth only 2d. 

 per ton. That is not the question at present. The 

 question is : whether land can take up the large quanti- 

 ties of ammonia, and other matters, out of the quantities 

 I have at the commencement mentioned : namely, out 

 of 10,000 tons, containing ;£'83's worth, to retain and 

 give out ^'32 or ^35's worth ; the land evidently can 

 do so, and a very much larger quantity. Whether the 

 crops obtain the chief advantage from the manure, when 

 there is such a large amount of it, or from the water 

 only, the marvellous amount of the crop is, I think, the 

 best answer. 



There is one point in these series of experiments 

 rather singular : the liquid-manure sent by Mr. Mechi 

 to Dr. Voelcker is exceedingly weak. It contains only 

 1-lOth the amount of ammonia in the other samples 

 used by Dr. Voelcker: in fact, it is weaker than London 

 sewage. 



I have not seen any explanation given in the Journal 

 upon this point. Does Mr. Mechi really prefer so very 

 weak a solution, or was it an accidental circumstance ? 

 I should like to ask Mr. Mechi if he finds that so weak 

 a solution is the best for grass ? If it be really true 

 that such is the case, will it not be a reason against any 

 attempt being made to separate the rainfall from the 

 sewage proper which many have recommended, and 

 also against the propositions to pass off (with or without 

 deodorizing) the liquid part into the Thames, sending 

 the remainder (the thick sludge) into the country, by 

 pipes, for grass-lands ? 



I trust that, in the above, I have pointed out some 

 facts worthy the consideration of those taking an interest 

 in this subject ; and that in the proposition of a plan for 

 the application of the sewage of London, I have shown 

 one which is both simple in its means of development 

 and unprejudicial to the population, while it requires no 

 adjuncts in the shape of large reservoirs for storing 

 the sewage, or manufactories for deodorizing, and for 

 separating the solid from the liquid part. And that to 

 the public there would be the means of receiving back 

 a very large annual sum, if it took the system into its 

 own hands ; or otherwise that a very profitable applica- 

 tion of funds could be made by private or associated 

 enterprize. 



THE USES AND QUALITIES OF WATER FOR IRRIGATION. 



The application of water for the purpose of irrigating 

 grass land has at the present time a peculiar interest, 

 arising from the fact that this is one of the most certain 

 modes of ensuring the production of early spring food. 

 It is one of the resources which we have at our disposal 

 for producing fodder at a time of the year when it is 

 especially valuable. Not that it is to be looked upon 

 as superseding the cultivation of other crops which are 

 of an established reputation, or even interfering with 

 them, but rather as an additional means which we have 

 easily within reach, in case of their failure or any defi- 

 ciency in their produce. The possibility of being oj 

 burthened with spring food is a position which wil 



:os||^ 



excite the fears of any of our stock-farmers, whilst the 

 satisfaction of a safe supply will prove a comfort to 

 many. A peculiar succession of unfavourable circiirn- 

 stances have this season placed our supplies of roots in 

 much danger, and a considerable quantity of food will 

 have to be consumed rapidly, because of the injury the 

 roots have received. This early consumption will seri- 

 ously diminish the store for spring use, and food avail- 

 able for stock will consequently be of more than usual 

 value to make up the deficiency. What has happened 

 this season may happen again, and it is as well to con- 

 sider each and every practice which is calculated to 

 afford security for the future. 



