Cane Soils and Artificial Manures. 287 
weight of mineral matter, which, according to Phipson'S 
analysis, would consist of : — 
58'06 pounds of Potassa 
6-45 „ „ Soda 
32-26 „ „ Lime 
20-97 „ „ Magnesia 
25-80 „ „ Sulphuric acid 
19-35 „ „ Phosphoric „ 
14-52 „ „ Chlorine 
138-70 „ „ Silicic acid or 'silica' 
6 - 45 „ „ Iron and manganese. 
322-56 
Silica, it will be seen, is assimilated by the cane in larger 
quantity than any of the other substances; but, fortunately 
it exists in enormous quantities in all soils, and no 
fears need be entertained of its ever becoming ex- 
hausted. The other substances, however, needed for the 
growth of the cane with the exception of iron, are usually 
present only in comparatively minute quantities, some of 
the most important ones being often met with only in 
' traces', or are even altogether absent. Thus, in the 
Report on Soils from British Guiana communi- 
cated to the Royal Agricultural and Commercial Society 
by the Hon. William Russell in 1880, we find ana- 
lyses of 134 samples of soil from various estates, made 
by Mr. THOMAS JAMIESON of Aberdeen ; and of that 
number a large proportion contained none at all, or only 
traces of lime, sulphuric acid, phosphoric acid and 
chlorine, as the following summary will show : — 
N n Number of Number of sam- Per cent, of sam- 
samples pies containing pies deficient 
containing none. 
only traces. 
in plant-food. 
Lime 
26 
62 
66 
Phosphoric acid.. 
44 
57 
74 
Sulphuric acid .. 
14 
59 
54 
Chlorine 
17 
46* 
47 
* Mr. Jamieson returned these 46 samples as containing a " moderate " quantity of 
Chlorine, but as he holds that a " trace " of that element is sufficient in a cane "soil 
see page 22 of the Report) it was thought proper to include them here, 
NN I 
