Gypsum as a Cane Fertiliser. 133 
from various agriculturists as to the action of gypsum, 
and the inquiry was far from being exhaustive or decisive. 
Many points left untouched were independently inves- 
tigated in France by M. DE ViLLELE, and in England by 
a Mr. SMITH. Smith's results, (obtained 1792-1794) as 
regards the action of gypsum on cereals, were dire6lly 
contrary to the decision of the French Committee. He 
found that the yield of grain on light soil was nearly 
doubled by the use of the fertiliser. Similar results 
attended his experiments with leguminous fodder crops. 
VlLLELE's experiments performed in the south of France, 
corroborated those of Smith, as far as they went, but 
seem to have been confined^to clover and sainfoin. 
It is evident, however, that these early inquiries were 
undertaken at a time when the chemistry of agriculture 
was but little understood. The simple salt, gypsum, 
consisting practically of lime, sulphuric acid and 
water, being placed on the same footing as a complete 
fertiliser, such as guano or stable manure, which contains 
every thing requisite for plant growth. 
The remarkable results achieved by gypsum in certain 
cases, however, were sufficient to attract the attention of 
scientific men, and to account for them, various theories 
have been from time to time put forward, and much 
controversy consequently excited. 
Sir H. Davy simply considered that gypsum bene- 
fited those plants that naturally contained a large 
proportion of calcium sulphate ; and only when the 
soil was deficient -in that substance was the benefit 
experienced. Davy did not even regard the gypsum 
as a source of sulphur, or of sulphuric acid, or of lime ; 
but that the mineral in its entirety was necessary to the 
