332 TlMEHRl. 
able proportion of the manures employed is wasted, 
partly by being converted into insoluble inert compounds 
in the soil, and partly by being washed out into the sea 
by drainage. 
The principal inorganic or mineral elements essential 
to the growth of the sugar cane required to be furnished 
in sufficient quantities by the soil naturally, or by 
manures mixed with the soil, are potassium, nitrogen, 
sulphur, phosphorus and calcium — these elements being 
ranged in the order of their relative importance. Most 
compound manures contain all these elements in greater 
or less quantity, but the money value of a manure 
depends almost wholly on the amount of potassium, 
nitrogen and phosphorus it contains ; compounds of 
sulphur and calcium being so abundant and readily 
procurable, and their value so small in comparison with 
the other elements specified, that they are almost 
altogether neglected in the pecuniary valuation. 
Furthermore, compounds of potassium, for some not 
very definite or satisfactory reason, are unwelcome in- 
gredients in cane manures, and are seldom met with in 
them to a greater extent than one or two percent. Thus 
we arrive at the remarkable fact that the sum of £195,000 
or thereabouts, annually spent by this colony on artificial 
manures, is almost entirely devoted to purchasing sup- 
plies of nitrogen and phosphorus ! It is true these ele- 
ments are very costly. Nitrogen is paid for at the rate 
of £100 per ton, whilst phosphorus costs about 
£110 per ton in the form of soluble phosphate, and about 
£62 per ton as insoluble animal phosphate ; insoluble 
mineral phosphate is, however, very much cheaper. 
There exists a great variety of substances suitable for 
