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The fact that phosphoric acid is an indispensable agent to the maintenance of vegetable life and the formation of grain, be coming daily more understood by the farmer, I think it needless to dwell further on this subject, or to speak of the benefit derived from the application of phosphatic manures.
There were a variety of artificial manures introduced into the market, each of which was claimed to be the most effective one.
The enormous success, however, attained by the use of dissolved phosphate or super-phosphate of lime, attributable to the solubility of portions of its phosphoric acid, soon established the character of its superiority, and has elicited the establishment of extensive factories for this class of fertilizers.
The importance of your discovery will be readily understood, from the fact that native phosphate of lime is of rare occurrence, mainly found in Spain and some few other localities, in deposits not large enough to be the object of distant commerce. Found some years ago in the formation of crag and green sandstone of England, its extraction was expensive, and thus the manufacture of the most desirable fertilizer, the super-phosphate of lime, was wanting a source of abundant supply of the main material.
This substance, in future and for a long time to come, will be supplied to the trade to the extent of its demands, without other limits but the labor on the island and the shipping facilities.
Before closing this report, I have to insist on this most important fact, that the phosphate found on the Island of Navassa is a mineral and not a guano, although known since its introduction into this market as Navassa Guano.
From their nature, the deposits of guano are limited, and their rapid exhaustion is already felt by the consumer, but the large development of phosphate of lime—a mineral substance—found on the Island of Navassa, gives the assurance of a permanent and rich yield. As a fertilizer, the action of the ammoniacal guano is mainly due, besides to its contents of phosphates, to the proportion, or the elements it contains for the formation of ammonia. The sources for this agent are numerous, and may be supplied to the wants of agriculture by many varieties of manure, blood, flesh, fish, etc., but the case is not
