Agricultural ChemUtry. 
469 
Table IV. 
Summary — showing the cliaracteristic action of Manures ou dififereut Croiis. 
Average Increase of Produce per Acre. 
Constituents of Manure 
(used separately or combined). 
Cereals. 
Leguminous 
Crops. 
Boots. 
Wlieat. 
Barley. 
Beans. jciover 
Turnips. 
Woburn. 
Holkham. 
Rothamsted. 
2. Potass, soda, and magnesia . 
3. Superphosphate of lime 
4. Do. do. and potass . 
lbs. 
lbs. 
lbs. 
270 
414 
97 
lbs. 
none. 
•i-a 
lbs. 
938 
843 
none. 
505 
lbs. 
1017 
1221 
113 
1580 
tons, c^vts. 
7 " U 
5 8 
16J0 
14-12 
2.332 
1714 
1870 
2317 
'!4 
none. 
0 " Gi 
1> Ammonia salts and superphos- ) 
8. Ammonia salts, potass, and super- \ 
9. Ammonia salts, potass, soda, maji;- "> 
nesia, and superphosphate of lime 5 
1757 
2357 
2511 
2956 
,3035 
2828 
3154 
175 
850 
1367 
none. 
108G 
925 
8 15i 
9 161 
10 12i 
Each entry in this Table (IV.) indicates the average increase 
per acre, calculated from all the eligible cases, throughout the 
entire series of experiments with the different manures and 
crops, and extending in most cases over several seasons. The 
method of the estimation is as follows : — namely, to find the 
increase in each case, or average of a number of cases, occurring 
in any particular season, by deducting from the total produce by 
any particular constituent or constituents of manure, that obtained 
without manure in the same season ; and an annual average is 
then taken of the increase thus obtained for the several seasons. 
In such a summary as is here given, we cannot expect exact 
numerical consistency in apparently similar cases, the results 
being frequently the average of very different seasons ; but 
we cannot fail to find prominent indications of the broad and 
characteristic effects of the respective manurial constituents or 
combinations on the respective crops. And, since in all cases 
(unless otherwise mentioned) the indications are derived from 
the growth of the crop in the manner described through several 
consecutive seasons, the characteristic exhaustion or requirements 
of the several crops, is thus very prominently brought to view. 
The manurial conditions enumerated in the first column of the 
Table, may be further explained, thus : — 
Potass, soda, and magnesia — generally as sulphates. 
Siiperphospliate of lime — bone ash, mixed with water, and de- 
composed by three-fourths of its weight of sulphuric acid, sp. 
gr. 1-7. 
Nitrate of soda — commercial. 
