674 
Analyses of Ashes of Plants. 
specimen of cbaff which we have examined did not contain the 
former, and the latter only in small quantity. We give here a 
table of the quantity of the different mineral matters contained in 
a ton of straw and of chaff; and also, for comparison, a calculation 
of the average quantity of these substances removed by the grain, 
straw, and chaff of an acre, calculated as before at 28 bushels of 
61 lbs. 
Silica . . . 
I'liosplioric Acid 
Sulphuric Acid 
Liime . . . 
Magnesia . 
Peroxide of Iron 
Potash . 
Soda 
Mineral 
matters in 
100 parts of 
Straw Ash. 
Mineral 
matters in 
100 parts of 
ChafT Ash. 
In a ton 
of Straw. 
In a ton 
of Chaff. 
Removed from an Acre. 
In 28 bushels 
of (frain, at 
61 lbs. 
(1792 lbs.) 
In 2109 lbs. 
of Straw and 
Chaff (18 c»t. 
91 lbs.). 
63-89 
2- 75 
3- 09 
7-12 
1- 91 
0-4) 
17-98 
2- 47 
81-22 
4-31 
1-8S 
1-27 
0- 37 
9-14 
1- 79 
lbs. oz, 
60 0 
2 8 
2 14 
7 0 
1 13 
0 6 
17 0 
2 5 
lbs. oz. 
172 3 
9 2 
a' 0 
2 11 
0 14 
19 6 
3 12 
lbs. oz. 
1 05- 
12 13 
0 lib 
3 .8fo 
" 3^ 
8 15 
0 l^iL 
lbs. oz. 
83 8 
7 3 
3 12 
7 1 
2 13 
0 10 
13 15 
0 13 
99-99 
99-98 
93-14 
212 0 
28 6^ 
119 11 
From tliis table we may learn that the straw and chaff of a 
given amount of crop (on the average of this year) remove from 
the soil together very little more than half the phosphoric acid 
contained in the grain — at the same time, however, requiring 
twice as much potash. 
The quantity of silica removed in the whole pi'oduce is very 
considerable, f cwt. of this substance being required for a very 
moderate crop. The addition of silicate of potash to the land 
must be tolerably liberal if it is wished to supply by its means the 
silica required for the wheat crop. A comparison of columns 3 
and 4 will show us that, weight for weight, wheat chaff contains 
three times as much silica and phosphoric acid as the straw ; and 
although, from the quantity of mineral matter it contains, and the 
woody nature of its vegetable substance, it may not be so nutritious 
a Ibod for animals as the straw, the manure into which it is con- 
verted must be regarded as much more valuable than that pro- 
duced from the latter. 
On the Ash of Barley and Oats. — Our information on these crops 
is comparatively very limited. Barley gives, as before mentioned, 
more ash than wheat ; but it is singular that the mineral matter ol' 
barley, deducting the silica, very closely resembles that of wheat ; 
thus, in specimen 64 we have 2'28 per cent, of ash, of which '74 
