NOTE I. (p. 297).

Peruvian Guano Imported into the United Kingdom, 1865-1893.

NOTE II. (p. 298).

Guano Deposits of the World.

NOTE III. (p. 303).

Composition of Concretionary Nodules.

(Analyses by Karmrodt.)

NOTE IV. (p. 306).

The following analyses, being the average of a large number of different samples analysed from time to time in the chemical laboratory of the Pommritz Agricultural Experimental Station, show the gradual deterioration of Peruvian guano, as regards its percentage of nitrogen, during the years 1867-81:—

NOTE V. (p. 309).

Composition of Different Guanos.

The following is a list of the more common nitrogenous and phosphatic guanos which have been used in the past or are at present in use. Those printed in italics are still being worked. As their value depends on their nitrogen and phosphoric acid, these alone have been given. The percentages must be taken as mere approximations, as the quality of different cargoes from the same deposits varies very much. The table may be found useful for reference.

Nitrogenous Guanos.

Phosphatic Guanos.

NOTE VI. (p. 314).

It may be of interest to refer to a theory put forward by Liebig as to the action of oxalic acid in guano. This, he considered, had the effect of gradually rendering the insoluble calcium phosphate soluble, and giving rise to the formation of ammonium phosphate and calcium oxalate. Such an action would probably take place were the guano allowed to ferment by itself. We know, however, that when it is brought in contact with the soil-particles, all its soluble phosphate is converted into precipitated phosphate.

NOTE VII. (p. 326).

Analyses of Dung of Fowls, Pigeons, Ducks, and Geese.
(Storer's 'Agricultural Chemistry,' vol. i. p. 367.)

According to a computation by a Belgian farmer, a pigeon yields about 6 lb. of dung in a year, a hen about 12 lb., a turkey or goose about 25 lb., and a duck 18 lb.