S26 
On Superphosphate of Lime. 
by Mr. Fothersill not only surpassed the bones, but also that which 
I had manufactured myself. Possibly the quantity of Mr. Fother- 
giU'smay have been too large for comparison ; but though I think 
my own method of preparing superphosphate a convenient one, 
v hen the bones are at hand, it appears also that if we can ensure 
the delivery of a genuine article, it will be still better to buy 
this manuie ready made. In this trial there could be no doubt 
that all the three forms of bones acted strongly, for the crop 
grew vigorouslv where they w ere used, while on spots where they 
w ere purposely omitted it could scarcely be said to grow at all ; 
and though, from late sowing, and from being left too thick, the 
turnips had not time to come to maturity, the result was quite 
decisive for our present comparison. About a fifth of an acre 
was weighed on each piece^ with the following results : — 
Stanure per Acre. Cost, Yield of Turnips. 
1. 20 bushels of bones . . . 55s. . . . 44^ cwt. 
2. 4+ bushels of bones with 
100 Ihs. sulphuric acid . . 2.2*. . . . 49+cwt. 
3. 2 cwt. :Mi-. Fothergill's su- 
perphosphate 14^.. . .53 cwt. 
present price . . 1 7^. 
The saving of imm.ediate expense by Dr. Liebig's discovery is 
certainlv very great, if we take it only as from bbs. to 225. per 
acre on the turnip land, which should be one quarter of the 
whole acreage of a light arable farm. The trouble of prepara- 
tion is slight, and of its application next to nothing : for ISIr. 
Hornsby inform.s me that his turnip-drill w ill distribute equally 
as small a quantity as 15 bushels over an acre: as then the 4^ 
bushels of dissolved bones do not require to be mixed with more 
than ten or fifteen bushels of earth, and his drill holds 2-5 bushels, 
the use of this compost would not rec^uire more than one stoppage 
for filling the drill on each acre. 
Mr. Fothergill's preparation, if the quantity assumed be correct, 
was still more successful, and having tried it elsewhere I am enabled 
to speak most highly of it. A neighbour, to whom I supplied 
some, found that 2 cwt. of this Superphosphate, costing then \ 4s., 
answered better on his land for turnips than 21 cwt. of the best 
Peruvian guano, for which he had paid 32.9. 
It is a srey damp substance, partly a powder, partly in tough 
lumps like dry dough. 7 he same lumps are found in the compost 
as 1 prepare it myself. It would evidently be a great waste of 
manure to drill these lumps into the land without reducing them 
to powder ; but this is rot easily done, for they are so tough that 
no pounding will crush them. As the point is one of importance, 
I may mention the method we at last hit upon. The whole mass, 
mixed with ashes, should be passed through a large coarse wire 
