532 
On the Food of Plants. 
It is exceedingly curious to observe that, while the body of a 
plant may abound in a soluble saline matter, sulphate of potash, 
its seed may be absolutely destitute of it ; and that, while the latter 
contains abundance of soluble phosphate, the plant itself is (piite 
free from that substance ! 
7. Lucern from a garden in Battersea Fields — a highly-manured 
soil : roots rejected. 
300 grains of dried plant gave of ash . 28' 1 grains. 
This contained, by analysis — 
Carbonate of potash 
Sulphate of potash 
Silica . 
Earthy phosphates . 
Carbonate of lime . 
Carbonate of magnesia 
Loss 
11-1 
8-65 
0-49 
s-l 
6-6 
0-2 
0-36 
28-1 
111 100 paits. 
39-5 
13-0 
1-7 
20-3 
23-5 
0- 7 
1- 3 
100-0 
It is impossible to speak with certainty concerning the arrange- 
ment of these substances in the living plant. Perhaps it may be 
something like the following : — 
Potash, combined with vegetable acid and little silica 9*53 
Lime, with vegetable acid .... 3*41 
Sulphate of lime . . . .• . . 2-87 
Phosphate of lime . . . . . . 5 • 7 
Magnesia, with vegetable acid . . . . 0"1 
The same plant grown in a field close at hand gave an ash almoil 
identical in composition. 
8. White clover — Hatcham, near Deptford : light sandy soil. 
500 grains of dried plants, without roots, gave of ash 33 "5 grains. 
20 grains of ash gave, on analysis ; — 
Carbonate of potash . . 7 ' 89 
Sulphate of potash . . 2 • 42 
Chloride of potassium . . 0*94 
Silica . . . .0-2 
Earthy phosphates, oxide of iron, &c. 6 • 1 
Carbonate of lime . . I'O 
Sandy matter . . . 0 • 8 
Water .... 0*3 
Loss . . . .0*35 
In 100 parts. 
39-45 
12-1 
4- 7 
1.0 
30-5 
5- 0 
4-0 
1-5 
1-75 
20 0 
100-0 
An ash evidently of the same description as lliat giveri by the 
lucern ; a plant of the same natural order. 
