ill its Relations to C/icmi.sli i/ and Geolufj)j. 
219 
ami that such is really the case you can easily satisfy yourselves 
by a very simple calculation. 
Take the case of pure dissolved bones, or superphosphate of 
lime, as it is often called. Suppose this to be made in the 
cheapest way, by reducinij three parts of bone-dust by means of 
one of stronj^ sulphuric acid, and that the water added to dilute 
the acid in the first instance, is afterwards driven off by drying-. 
This will be unadulterated dissolved bones ; four tons of which 
will contain three of bones and one of acid. And what will be 
the lowest cost, taking the bones at 5/., and the acid (bought in 
large quantities) at 11. a ton? bl. lOs. a ton is the cost of the 
raw material, and if we add only 1/. for labour, the cost is G/. 10*. 
a ton without any allowance for interest of capital, or for profit. 
Now, if you increase this sum by a fair profit, by charges for 
carriage, for commission allowed to agents — usually IZ. a ton, 
— for discount, waste, bags, &c., you will be able to judge whe- 
ther those who profess to sell even this simple article of dissolved 
bones at G/. or 71. a ton, can really send yon what either you 
unreasonably expect, or they untruthfully ofl'er to you at so low 
a price. Such cheap articles are in reality diluted, with water 
left in them, with gypsum introduced to dry them up, or with 
some manufacturing refuse of uncertain composition. They are 
thus necessarily subjected to those variations in quality to which 
careless workmen everywhere give rise, and to which the refuse 
and other admixtures employed are themselves liable.* 
One remedy and sure check for this state of things — which in a 
few years will no doubt come to a natural end — is to be found in 
the general diffusion among agricultural improvers of that limited 
amount of instruction which shall enable them to manufacture 
such mixtures for themselves. That this mode of meeting the 
difficulty is gradually making its way, I know from the numerous 
communications I receive regarding mixtures prepared and em- 
ployed by practical farmers themselves ; and that in this part of 
England the practice is on the increase, may be inferred from 
a statement lately published, that in the town of Spalding alone 
* This you will understand applies only to pure dissolved bones. The 
name of superphosphate of lime in the manure market is, iinlortLinately, 
f^iven to preparations of very diflerent kinds. Some make it by dissolving 
burned bones in acid, some common bone-dust, some Saldanha Bay guano, 
some the coprolites of the green-sand, and so on. This causes a diversity 
of composition in articles sold under the same name, which is injurious 
both to the consumer and to the maker. In tlie absence of other standards 
I would venture to suggest, that in every article sold under the name of 
superphosphate, the proportion of ))liosphate of lime (or of j)hosphoric 
acid) and of dry animal matter should be guaranteed by the seller. One 
means of comparison would thus be atibrJed to the buyer. 
