802 VALUE OF DIFFERENT MANURES. 



air, the number designating these being 1554, we have only to make 

 a simple equation in the following terms : — 100 : 3d. : : 1554 : a, to 

 have the solution : =3s. lOhd. 



The most careful consideration of the relative value of different 

 manures under th^ guidance of the analytical elements which I have 

 indicated, justifies the preference which is given in practice to one 

 kind over another, which on simple examination appears to offer 

 greater advantages. Thus, by diffusing oil-cake through water, and 

 leaving the mixture to ferment, a manure is obtained which presents 

 all the characters, which possesses all the properties of human soil 

 that has undergone fermentation in privies or cess-pools. And it is 

 to this mixture of putrid oil-cake that the husbandmen of French 

 Flanders have recourse, as we have seen, when their supply of 

 night-soil runs short. When oil-cake is low in price, say about 3^. 

 3d. or 35. 4d. per cwt., it might seem advantageous to manufacture 

 Flemish manure with it ; expensive carriage and time would be 

 saved ; for night-soil has generally to be fetched from a distance, 

 and containing but 0.002 (y/o o^hs) of azote, it is bulky, and its equiv- 

 alent is in the same proportion high. Cameline oil-cake contains 

 0.055 (ylf^ths) of azote ; to make Flemish manure that should con- 

 tain 0.002 of azote, it would be requisite to add to every 100 parts 

 of cake 2,650 parts of water ; the cwt. of this manure would then 

 come to l^d., while Flemish manure prepared with night-soil, would 

 cost the farmer but l^d. I have here taken the cake at a tow price; 

 were it 7^. 6d. per cwt. instead of 3*. 9d., which is perhaps much 

 nearer its usual average cost, it is obvious that the cwt. of manure 

 prepared from it, would cost twice as much more. 



The proportion of azote, the value, and the equivalents of the 

 several manures are given in the table, both for the substances ab- 

 solutely dry, and for the condition in which they are commonly em- 

 ployed. This distinction is one of great importance. The water, 

 the quantity of which is indicated in the first column, is a most 

 variable constituent ; its presence, of course, depreciates the ma- 

 nure in the precise ratio in which it occurs. The reference of all 

 the elements of each particular manure to that manure in a state of 

 absolute dryness, is a very important feature in the table. In pur- 

 chasing manures, the precaution of drying them chemically must 

 never be neglected, more especially in connection with articles, 

 which by their nature are capable of absorbing water in consider- 

 able, and often in very different, quantities. 



