116 Compensation for Unexhausted Manurial Values. 
parts advantageously used for grass land ; in other parts no 
benefit is experienced from it. Basic slag, again, is invaluable 
on some lands, but useless on others. Bones, in their different 
forms, are very variable as regards their results ; while lime, 
though indispensable on some soils, may not be called for at 
all on others. 
The matter of the prices charged for manures is again one 
beyond our power to check ; we must assume these to be fair. 
Inasmuch, however, as the Fertilisers and Feeding Stuffs Act 
compels the giving of the analysis on the invoice, a safeguard 
is introduced by which a competent valuer can form some 
opinion, or upon which expert opinion can be taken, as to 
the reasonableness of the price charged. We must, therefore, 
leave it to be understood that, while the Tables we have set 
out are to be taken as a guide, they must be subject to such 
modifications as the particular circumstances of the case 
demand. 
The most recent information as to the residual value of 
fertilisers is that obtained from a large series of experiments 
which were commenced in 1904 in Little Hoos Field, Rotham- 
sted, and which are still in progress. These have already 
given certain definite issues regarding the residue left for 
subsequent crops after one or more have been taken off the 
land. 
Perhaps one of the most striking points brought out is that 
phosphates, whether derived from superphosphate, bones, or 
basic slag, behave much alike as regards their residues. A 
further point is that in nitrogenous manures like Peruvian 
guano, fish guano, meat meal, &c., as also in manure cakes, the 
greater portion of the value is used up in the first crop. 
Slowly-acting organic manures, such as shoddy, hoofs, and 
horns, &c., last for a longer period, and for this duration 
allowance should be made. 
As regards lime, the Woburn Experiments have clearly 
shown the duration of this both on arable and -on grass land. 
Lastly, the Rothamsted and Woburn Experiments alike have 
demonstrated that for such soluble salts as nitrate of soda, 
sulphate of ammonia, and the like, there is practically nothing 
left over after the first crop has been taken off. 
Acting on these data, we have drawn up the following Table 
of compensation (page 117) for the use of fertilisers generally. 
The first point that will probably strike the practical man as 
being somewhat strange is the putting of superphosphate and 
bones on the same level. This, however, is the direct outcome 
of the experiments on Little Hoos Field, and superphosphate 
must clearly not be considered the transient material which it 
is too often supposed to be. On grass land, bones may be 
