390 



THE FARMER'S MAGAZINE. 



the season of application. The latter end of April 

 and the first part of the month of May is the most 

 common time of using these light substances. 

 Dews and light moistures fasten the light bodies on 



the leaves of the plants ; heavy rains are injurious 

 in washing them entirely away. For top-dressing 

 vetches, they are most peculiarly apphcable and 

 very highly useful. J. D. 



THE COMMERCIAL VALUE OF MANURES, 



In the last number of the Journal of Agriculture of 

 Edinburgh, Professor Anderson, in a paper entitled 

 " Instructions to Farmers on the Reading of 

 Analyses and the Valuation of Manures," furnishes 

 some details which are interesting, and when qua- 

 lified by more accurate and recent statistics than the 

 Professor evidently has access to, may be usefully 

 placed on record for more general reference. It is im- 

 possible, as he well observes, to form an estimate, with 

 accuracy, of the sums annually expended by the British 

 farmer on the purchase of artificial manures, because 

 no means exist of obtaining an exact statement of the 

 quantities of some of the substances used for agricul- 

 tural purposes ; but an estimate may be formed which 

 approximates to the truth. " When the substances," 

 he adds, " are of foreign origin, and used exclusively 

 for agricultural purposes, no difficulties are experi- 

 enced ; and we thus leai'n, from the Board of Trade 

 returns, that the value of the guano imported into this 

 country in the year 1858, and retained for home- 

 consumption, amounted to no less than j^3, 857,424. 

 Tliis sum, however, is considerably above the average ; 

 but it is probable that the usual import is not less than 

 £2,500,000." Dr. Anderson's commercial researches 

 do not seem to be very extensive, however accurate bis 

 chemical investigations may be. Had he been a care- 

 ful reader of the Mark Lane Express, or Far7ner's 

 Magazine, and scanned more closely the annual re- 

 turns of the Board of Trade, he would have come 

 nearer the mark in his estimate of the cost and quan- 

 tities of artificial manures. Taking the average of the 

 last five years the consumption of Peruvian guano has 

 been 220,000 tons per annum — worth, at £^12 per ton, 

 i^2,540,000, which corresponds closely with Professor 

 Anderson's assumption, although there is besides a 

 small quantity of other guano imported. 



" Next to guano the largest consumption is that of 

 bones, of which, including bone-ash, 84,000 tons are 

 imported annually. In addition to this, however, it is 

 necessary to take into account the bones collected in 

 this country, of which it is only possible to form an 

 approximate estimate. In Glasgow there are collected 

 about G tons 2 cwt. of bones for every 1,000 of the 

 population, and if this were the case all over the 

 kingdom the quantity would amount to upward of 

 150,000 tons. But in country districts a considerable 

 quantity of bones are lost, the consumption of meat 

 is also much smaller than in towns, and I do not 

 think the quantity of bones collected can be safely es- 

 timated at more than 50,000 tons— giving for the total 

 quantity of bones used 134,000 tons. A very large 

 proportion of the bones collected in this country is 



converted into animal charcoal for the sugar refiners j 

 but as the spent charcoal eventually finds its way into 

 the hands of the manure manufacturers, it is not ne- 

 cessary to take this into consideration ; but I estimate 

 the quantity used in the manufacture of ivory-black, 

 for turning, &c., at 20,000 tons, leaving 114,000 tons 

 to be employed in agriculture. Of this probably 

 40,000 tons are used in bone-dust, costing the farmers 

 J'G per ton, which is equal to .£210,000, and 74,000 

 tons are converted by the action of acid into 110,000 

 tons of superphosphate, which, at £7 per ton, is worth 

 .£770,000." Upon this we would remark that the bones 

 collected at home were estimated ten years ago to exceed 

 70,000 tons by Mr. Poole, in his " Statistics of British 

 Commerce." That gentleman, from his position as traf- 

 fic superintendent of the London and North Western 

 Railway, had great facilities for investigation into the 

 collection and employment of various substances. We 

 have invariably found his estimates fully boi-ne out, and 

 looking at the improved condition of the country, and 

 the increase of population in the last decade, we think the 

 quantity of bones available at home may still be taken 

 at fully 75,000 tons. If to this we add the average 

 imports 85,000 tons, we have a total of 160,000 tons, 

 which we may apportion, according to Professor 

 Anderson's plan (first deducting 20,000 tons for turn- 

 ing, &c.), and we shall have, say 60,000 tons used as 

 bone-dust, at £6 per ton, and 80,000 converted into 

 120,000 tons of superphosphate at the same price. 



The consumption of mineral phosphates, according 

 to Professor Anderson, is about as follows : — 



Cambridge coprolites , 40,000 



Suffolk coprolites 3,000 



Apatite and all other mineral phosphates 5,000 



48,000 

 which, being entirely converted into superphosphate, 

 will yield 72,000 tons, at £5 value— £360,000. Of 

 nitrate of soda the average imports amount to 26,000 

 tons, of which about one-half— woi'th, at £15 per ton, 

 £195,000 — is used for agricultural purposes. The 

 average imports are not so high as 26,000 tons of 

 nitrate, although that quantity was imported last year, 

 unless it is meant to include saltpetre. 



Of suljihate of ammonia it is difficult to obtain any 

 definite information ; but the opinion of persons con- 

 versant with the manufacture is, that about 6,000 tons 

 are used as manure — which, at £15 per ton, is worth 

 £90,000. 



If to this be added the sum of £50,000, as covering 

 the value of the blood, fish offal, animal matters of all 



