348 AGRICULTURE [MANURES. however, they can call the chemist to then- aid, with the certainty of ascertaining the real character of the articles which they are invited to purchase. If purchasers of ma nures would but insist in every instance on getting from the seller an analysis by some competent chemist, and along with it a written warrandice that the stock is of the quality therein indicated, detection and punishment of fraud would be easy. In regard to superphosphate of lime, the farmer can purchase bone-dust and sulphuric acid and prepare it liimself. We conducted this process for several years in the following way: A trough was provided 7 feet x 3 4 x 2 10, made of 2^-inch deal, strongly jointed, and secured at the corners by wooden pegs, as iron nails would be corroded by the acid. This holds conveniently 48 bushels of bones. The heap of bone-dust is then gone over with a barley riddle, and the small dust which passes through this is laid aside to be used as a drying material for the other portion, after it is subjected to the acid. We find that a third part of the bone-dust passes through the riddle. Three bottles, or carboys as they are called, of concentrated acid, averaging 180 tt>. each, are then emptied into the trough and mixed with cold water at the rate of 1| of water, by measure, to 1 of acid. In practice, the water is poured in first and then the acid. Into this mixture 48 bushels of bones, previously measured and laid close to the trough, are rapidly shovelled by two labourers, who will do well to be attired in clothes and shoes past spoiling. So soon as the bones begin to be thrown in, violent ebullition commences. By the time that the whole of the bones are thrown in, there will be barely liquid enough to moisten the last of them. The labourers therefore dig down at one end of the trough till they reach the bottom, and then carefully turn back and mix the whole quantity until they reach the other end. The surface is then levelled and covered with a layer of the dry riddlings two inches thick. In this state it is allowed to remain for two days, when the trough is emptied, and the same process is repeated until the whole quantity is gone over. When shovelled out of the trough the bones are found to have become a dark-coloured paste, still very warm, and emitting a sweetish smell While one person throws it out, another adds to it its proportion of dry riddlings, and mixes them carefully. This mass is heaped up in the corner of a shed, and augmented at each emptying of the trough, until the requisite quantity is obtained. After this the mass is care fully turned over several times, at intervals of five or six days, and is then dry enough for sowing either by hand or machine. Some prefer moistening the bones with boiling water, and then adding pure acid as they are shovelled into the trough ; but by first mixing the acid and water there is greater certainty of all the bones being equally acted upon. There is also great convenience in using the finest portion of the bone-dust for drying the other, as suitable material for this purpose is sometimes difficult to procure. The homely process now described is quite inferior to, and more costly than, that pursued in factories, and should only be resorted to when a genuine article cannot otherwise be obtained. We have referred to superphosphate of lime prepared from bones. A new source of supply has, however, been discovered of late years, the extent and importance of which is becoming more apparent as investigation proceeds. We allude to those phosphoric deposits found in such abundance in the crag, and upper and lower green-sand formations in the south of England. The existence of these fossil animal remains was first pointed out by Drs Mantel and Buckland, though it is to Professor Henslow that we are indebted for having called attention to their eminent agricultural value, and described the localities whence they may be most readily obtained. These remains consist of the fractured and rolled bones of sharks, gigantic sea-lizards, and whales, which at one period of our earth s history must have existed in myriads in our oceans and seas. Mixed with these bones are found many fish-teeth and shells of different species, and likewise immense numbers of rolled, water-worn pebbles, which at one period were imagined to be the fossilised ex crements of the animals themselves, and were on this account called coprolites by Professor Henslow and others. Although this has since been proved a mistake, the name has been adopted, and will probably be continued. These fossil bones, and so-called coprolites of the crag, are found in enormous quantities on the coast of Suffolk, Norfolk, and Essex, whence MrLawes of Bothamstead obtained nearly the whole of the material which he employed in the preparation of his well-known " coprolite manure," or " Lawes super phosphate." Already, it is believed, several thousands of tons of these fossils in one form or other are annually sold for manure, with a rapidly increasing demand. Those found in the crag formation are exceedingly hard, and require to be ground by powerful machinery, and dissolved in sul phuric acid, to render the phosphate of lime available as manure. Fossils, though less abundant in the green-sand, can be reduced to the requisite fineness by simple machinery, and are then fit for agricultural purposes without any chemi cal preparation. They are found plentifully in the parish of Farnham, so long celebrated for the excellence and abun dance of its hops, which are now discovered to be due to the presence in the soil of these fossil remains. The discovery of these mines of manure in various parts of our country was made most seasonably, and has proved of immense national importance. When Liebig predicted that, " in the remains of an extinct animal world England is to find the means of increasing her wealth in agricultural produce, as she has already found the great support of her manufactur ing industry in fossil fuel," he was regarded by many as merely indulging a fine philosophic fancy ; but enough has already been realised to convince the most sceptical of the importance of the data on which he founded his opinion. 1 On mixing a quantity of bone-dust with its own bulk of mould or sand, and wetting the whole with the liquid which oozes from the dung-heap, violent fermentation immedi ately ensues, dissolving the bones, and making them more readily available for the nourishment of the turnip crop. Many farmers are so satisfied with this preparation, that they dispense with the acid. This is not judicious, as the superphosphate of lime is a more valuable manure than bones dissolved by simple fermentation. Bones are sometimes applied as a top-dressing to grass land with singular success. " This Cheshire practice con sists in applying an extraordinary dose of bones to pasture- land. For pasture land, especially the poorer kind, says Mr Palin, there is nothing equal to bone manure, either as regards the permanency of its effects, or the production of a sweet luxurious herbage, of which all cattle are fond. Many thousand acres of the poor clay soils have been covered with this manure during the last eight or ten years. The average quantity used is about a ton and a half to the acre ; it is therefore a landlord s improvement, on which seven or eight per cent, is generally paid. Boiled bones act as long as unboiled bones, retaining the phosphorus, though not so quickly, having lost the animal matter. Boiled bones (1845) cost 3, 10s. per ton ; the outlay then was five guineas per acre, sometimes 7 or 8. I have known/ says a correspondent, many instances where the annual value of our poorest clay lands has been increased by an outlay of from 7 to 8 an acre, at least 300 per cent. ; or, in other words, that the land has been much cheaper after this outlay at 30s., than in its native state at 10s. per acre ; with the satisfaction of seeing a miserable covering 1 Journal of the Royal Agricultural Society of England, vol. ix.
p. 56, and vol. xii. p. 91.
