Home Mannjacturc of Portable Manures. 
271 
farmer can mahe as cheaply as those extensively enp;agcd in the 
trade, for quantity must always influence the cost of production ; 
but 1 am of opinion that they can make at a cheaper rate than 
the dealers sell, or in other words, that the difference of the cost 
of production in the two cases is not equal to the profits of the 
trade, ranging as these do at from 15 to 25 per cent. The manu- 
facturer may not have all this to himself : agents' commission 
(5 per cent. — I have known 10 per cent, and even more paid) 
must be provided for ; hut. the farmer pays for the whole* Manures 
are now so numerous, and sold under so many different names, 
that it would fill a page to enumerate the half of them, to say 
nothing of many that are bought from some noted maker and 
again sold (at a good profit) as the buyer's otmi make. It is, 
however, satisfactory to observe a marked improvement in manu- 
factured manures generally of late years, which 1 believe in a 
great measure to arise from the demand that is now made for an 
analysis. 
Bones and their products for Manure. — The various materials 
from which superphosphate of lime is derived, such as bones, 
English or Foreign, bone-ash, animal charcoal, apatite, and 
coprolites, differ in value according to the proportion of bone 
earth which they contain. This proportion will vary from 46 
per cent, in raw bones, to 50 and 60 per cent, in boiled bones 
or coprolites, and 60 to 80 per cent, and upwards in bone-ash, 
apatite, and some other foreign substances. We see, then, how 
wide a range is included in the value of these materials. 
Per Ton. 
Assuming bone-ash containing 60 per cent., to 
te worth .. 4L 5s. 
The proportionate price for 65 per cent., ■would he 4Z. 15s. 
„ „ 70 „ .. U. 5s. 
„ ,, 75 to 85 ,, 6Z. to 6^. 15s. 
The value of the superphosphates is, however, estimated by the 
source from whence they are derived, as well as by the percentage 
of soluble and insoluble phosphates they yield. Superphosphates 
made from coprolites and. apatite, although they may contain the 
same percentage of soluble and insoluble phosphates as from 
ground bones and bone-ash, do not command the same price, 
being of less value : hence the practice of most manufacturers is 
to make a distinction between the two — bone superphosphate 
(commonly called dissolved bones) being usually sold " warranted 
free of any admixture of coprolites." 
It is unnecessary here to enter into the details of the machinery 
at present in use in a large manufactory for the preparation of 
superphosphates, where the object is the production of the greatest 
* It is a common practice to weigh in the bags, making no allowance for tare. 
