288 
TlMEHRI. 
In order to show the average composition as well as 
the variation met with in the soils employed for 
growing canes in British Guiana the following table 
has been compiled from numerous analyses (about 
150) made by Dr. Alfred Sibson, Dr. Newlands, Dr. 
Phipson, Mr. Scard, Mr. Jamieson and myself, of 
soils from estates in all parts of the colony. 
Percentage composition of British Guiana Cane Soils, exclusive of 
Water and Organic Matter. 
Constituent. 
Sukface Soil. 
Sub-Soil. 
Mean. 
Maxi- 
mum. 
Mini- 
mum. 
Mean. 
Maxi- 
mum. 
Mini- 
mum. 
Potassa 
0-21 
0-57 
0-02 
019 
0-56 
002 
Soda 
0-20 
098 
o-oi 
0-27 
2-22 
0-01 
Lime 
0-20 
099 
o-io 
0-22 
0-62 
0-08 
Magnesia 
0-50 
1-44 
o-ii 
0-53 
1-41 
0-08 
Ferric Oxide 
4-51 
11-07 
1-78 
5-10 
10-68 
2-22 
Alumina 
8-98 
1535 
3-66 
8-90 
12-95 
2-36 
Sulphuric Acid ... 
008 
031 
Trace 
0-07 
0-50 
Trace 
Chlorine 
003 
0-08 
None 
0-03 
0-09 
0-01 
Phosphoric Acid.. 
0-09 
0-24 
0-02 
0-08 
0-18 
002 
Silicious Matter.. 
73-58 
83-25 
59-60 
78-04 
82-58 
70-88 
Nitrogen 
025 
0-85 
0-05 
0-16 
041 
0.05 
It will be noticed that with the exception of 
silicious matter and iron, the mineral substances re- 
quired for the growth of the cane exist only in the 
proportion of a fraction of a per cent, Nevertheless, 
