Soluble and Imoluhle Phosphatci^. 
157 
mineral superphosphate, 20 tons 15 cwt. 2 qrs. 24 lbs. of 
swedes per acre, or an increase of 6 tons 1 cwt. 1 qr. 20 lbs. 
over the unmanui'ed plot. 
In vol. vi. of the ' Journal of the Royal Agricultural Society,' 
Dr. Daubeny records experiments with ground Spanish phos- 
phorite and dissolved phosphorite : — 12 cwts. of ground phos- 
phorite per acre produced 28,1)39 lbs. of turnips ; and 12 cwts. 
of Spanish phosphorite, treated with acid, produced 30,869 lbs. 
As far back as 1844 Mr. G. B. Lawes experimented at 
Rothamstcd on the comparative efficacy of ground mineral 
phosphates, and the same material decomposed and rendered 
soluble by sulphuric acid. A detailed account of these results 
will be found in vol. viii. part ii. of the 'Journal of the Royal 
Agricultural Society of England.' Mr. Lawes records in this 
paper three experiments which appear to me to prove conclu- 
sively the vastly superior efficacy of dissolved mineral phosphates 
in comparison with the same materials not treated with acid 
and merely ground. 
Toil?, cwts. qrs. 
No. 1. 3 cwts. of "round apatite (a mineral phos-l „ r. c ^ 
j.bate)save .. .. \. _ .. } ^ 1 0 of turnips. 
No. 2. 3 cwts. of superphosphate, made fronil ^ 
2 cwts. of apatite and decomposed by acid, gave/ ^' " 
Xo. 3. 270 lbs. of apatite and 104 lbs. of sol-) - '< 
phuric acid, gave j ' " 
In Mr. Lawes' experiments made in 1845, the produce of 
turnips also was larger in the case of bone-ash treated with 
sulphuric acid than with ground bone-ash. Thus, 400 lbs. 
calcined bone-dust produced 10 tons 4 cwts. of white turnips ; 
and 400 lbs. calcined bone-dust with 268 lbs. sulphuric acid 
gave 13 tons 11 cwts. of white turnips. 
Sir Harry Verney also made experiments with ground and 
dissolved Spanish phosphorite, in 1855, on barley. Nothing 
gave 3 qrs. 6 bushels 2 pecks of barley. Undissolved Spanish 
phosphorite, at a cost of 18.s. per acre, produced 5 qrs. 3 bushels 
2 pecks of barley ; and Spanish phosphorite and acid, at the 
same cost, yielded 6 qrs. 3 bushels 2 pecks of barley. 
Mr. Hannam winds up his account of numerous experiments 
with raw and dissolved bones as follows : — ■ 
" The general advantages arising from the use of dissolved 
bones instead of ordinary bone-dust are : 
" 1. Great saving in the cost of the application. 
" 2. A gain in the greatly augmented produce. 
" 3. A crop which grows so quickly that the fly and other 
enemies of the turnip-infancy cannot affect it so seriously 
as in ordinary cases. 
