Compensation for Unexhausted Manurial Values. 105 
It lias been thought desirable, in addition to putting forward 
our revised Tables and our replies to the enquiries made, to 
contribute a paper in which there would be set out the general 
considerations which have weighed with us in giving our 
recommendations. 
By the kind consent of the Central Association, permission 
has been accorded us to publish this in the Journal of the 
R.A.S.E., where our former Tables of 1902 appeared. 
Reasons for Revision of Previous Tables. 
We propose considering first the circumstances which have 
led to a revision of the earlier Tables. These reasons are 
twofold — (1) The rise in prices of manurial ingredients ; (2) 
the growing feeling that the spreading of compensation over a 
period of four years is alike inconvenient and not borne out 
by recent investigation nor in actual agricultural practice. 
Rise in Prices of Manurial Ingredients. 
It may at once be pointed out that fertilisers generally have 
decidedly gone up in price since 1902. This applies mainly to 
nitrogenous fertilisers, potassic ones having remained much 
about the same, while phosphatic fertilisers have increased 
slightly, though, perhaps, hardly materially. The rise in unit 
value of nitrogen, however, has been very marked. Sulphate 
of ammonia, for example, has risen in price, since 1902, from 
12 1 . a ton to about 14?. ; nitrate of soda, similarly, from about 
10 1 . a ton to 12?., and other nitrogenous materials in proportion. 
In our former Tables we put the unit value of nitrogen, as 
found in common nitrogenous manures used on the farm (such 
as sulphate of ammonia, nitrate of soda, bone meal, fish manure, 
blood, shoddy, guano, &c.), at 12s. per unit. A revision of 
current prices for the above materials warrants us in now 
putting the unit value of nitrogen at 15s. instead of 12s. as 
formerly. 
We do not consider it necessary to make any alteration as 
regards phosphoric acid. There has been a slight rise in the 
price of phosphatic manures, but not a material one. Super- 
phosphate, basic slag, and bone dust, for instance, have remained 
much as they were. This is also the case with fertilisers 
supplying mainly potash ; Kainit, for instance, has remained 
steadily at about 50s. per ton. 
The question was, of course, present in our minds, whether 
the change in prices was merely a fluctuation, or a permanent 
change. We have come to the conclusion that the rise is 
likely to be sustained for some time to come, and is not 
merely temporary, and we have felt that we should alter 
our Tables in this direction accordingly. 
