284 
Commercial Value of Artificial Manures. 
It is, therefore, simply absurd to put the same value on 
insoluble phosphates, irrespective of the form in which they 
occur, since in a lurnip-manure their Avorth may range from 
absolutely nothing up to 11., 81., or even 121. a ton. 
As regards nitrogen, this element may be present in the shape 
of an ammonlacal salt, or of nitrate of soda, or uric acid ; or, again, 
in shoddy, whale-blubber, fish-refuse, horn and hide clippings, 
scutch, leather-refuse, and many other forms. In all these dif- 
ferent forms nitrogen has a different agricultural and commercial 
value, and it is therefore unreasonable to assume the same price 
in calculating the money-value of the nitrogen which a manure 
may contain in so many varied shapes. 
Besides this, some purely practical matters have to be well 
considered before a fair estimate can be given. In some instances 
superior composition in regard to ingredients may be more than 
neutralised by imperfect pulverisation or by a damp and lumpy 
condition, tending to inequality of distribution and irregularity 
in the growth of the crop. A fine state of division, dry condi- 
tion, and uniformity of composition cannot be secured without a 
considerable increase in the cost of manufacture. No allowance, 
however, is generally made for this expenditure of money by our 
rule-of-three chemists ; or if anything at all is allowed, the same 
manufacturing expenses are assumed whether the manure be 
fine, dry, and uniform, or the reverse. Injustice thereby is done to 
honest and skilful manufacturers, and at their expense the sale of 
apparently cheap but really inferior manures is encouraged. Is the 
manure dry enough to admit of equal distribution on the land ? — 
is it very fine, or coarse and lumpy ? — is it uniform in composi- 
tion ? — are the ingredients and their relative proportions in a 
manure really useful for the purpose for which the latter is 
recommended ? — what facilities are there in a particular locality 
for procuring the required fertilisers ? — and many similar ques- 
tions that do not enter for a moment into the mind of a mere 
" calculating machine " require to be well weighed before any- 
thing like a just estimate of the money-value of a manure can be 
given. 
In a highly-concentrated, well-prepared superphosphate, I have 
already noticed that soluble phosphate has a somewhat higher 
commercial value than in an ordinary sample. Concentration 
or dilution of all the more effective fertilising constituents simi- 
larly affects the commercial value of other manures. It is there- 
fore evidently unfair to take as a standard the price at which 
ammonia, phosphates, <Scc., can be purchased in Peruvian guano, 
in calculating the money-value of nightsoil, sewage, and other 
bulky fertilisers. 
A very striking example, showing how much bulky and, com- 
