Composition and Value of Guano. 



199 



the express purpose of throwing light upon the agricultural value 

 of guano, and upon the extent of variation in its composition, 

 great pains have been taken to render the results perfectly trust- 

 worthy and unexceptionable. 



I am indebted to Mr. Lawes for several of the specimens of 

 which the analysis is given, and for much information and assist- 

 ance in the course of my inquiries. The samples given me by 

 Mr. Lawes were taken from the cargoes in the docks, mostly by 

 himself, and with every care that they should represent truly the 

 bulks from which they were separated; that they are really fair 

 averages of the respective cargoes I shall attempt to show in a 

 subsequent part of this paper. 



To Messrs. Gibbs and Sons, the importers of Peruvian guano, 

 1 owe the opportunity of selecting specimens of this year's im- 

 portation. These gentlemen, having become aware of my inten- 

 tion of publishing the results of my earlier analyses, placed them- 

 selves in communication with me, and afforded me every facility 

 in taking samples from the ships in dock. 



In addition to the analyses made in my own laboratory, I am 

 enabled, by the kindness of Mr. Lawes, to enrich this paper by 

 the introduction of many others which have been from time to 

 time made for him by Dr. Ure and Mr. Teschemacher, and which 

 are now published for the first time. 



The following analyses of different specimens of guano will 

 present to the reader its ultimate composition (more especially as 

 regards the mineral portion), and will enable him to judge to 

 which of its constituents, according to the rules before laid down, 

 he should attribute its principal value in relation to other available 

 manures. 



Table L — Composition of Eight Specimens of Peruvian Guano.* 



* For methods of analysis, &c., see Appendix 



