138 TlMEHRI. 
In discussing whether gypsum is advantageous as a 
cane manure in British Guiana, we will consider it first 
as a plant food. It is a well known fa6t that the soils of 
the colony are deficient in lime, and that they are defi- 
cient in sulphuric acid (or sulphates), was shown by the 
numerous analyses made by T. JAMIESON, of Aberdeen, 
whose report on the cane soils of the colony was com- 
municated to the Royal Agricultural and Commercial 
Society by the late Hon. WlLLIAM RUSSELL in 1880. 
JAMIESON found that of 134 samples from the various 
estates in which Mr. RUSSELL was interested, 14 sam- 
ples contained no sulphuric acid detectable by analysis, 
whilst no less than 59 samples contained only traces. 
Taking also the analytical results of 145 samples of cane 
soils from various parts of the colony obtained by SlB- 
SON, Newlands, Phipson, Scard, and myself, the 
mean amount of sulphuric acid present is only - o8 per 
cent., the maximum being 0*2 and the minimum, a mere 
trace. 
But the analysis of the ash of sugar cane shows that 
sulphuric acid is present in it in considerable quantity, 
perhaps even to a larger extent than phosphoric acid. 
Thus, according to the analyses of 12 samples of stripped 
cane made by STENHOUSE, the mean amount of sul- 
phuric acid in the ash is 6*62 percent., and of phosphoric 
acid 6"8i per cent. ; whilst PHIPSON found in the ash 
of a ripe cane including the leaves, 8 per cent, of sul- 
phuric acid and only 6 per cent, of phosphoric acid The 
importance of phosphoric acid is fully recognised, and 
is provided for by the abundant phosphatic manures used 
in cultivating the plant, but an equal importance is, by 
no means, attached to sulphuric acid, and canes have to 
