140 Mr. Denham Smith on the Composition of Guano, 



products, — one equivalent of urate of ammonia combining witli 

 8 equivalents of water and 1 of oxygen, and producing 5 equi- 

 valents of oxalate of ammonia. 



Uric acid . . C^" W W 0« Oxalic acid . C^ O^ 



Ammonia . . N H^ Ammonia . . N H^ 



CioN5H7^6r C^O^ NTl^^ 



Water, 8 eqs. H^ O^ 5_ 



Oxygen, 1 eq. O C^^O'^N^H'^ 



'C'ONTTsOi^ 



This theory has simplicity to recommend it, and is in ac- 

 cordance with observed facts, so far as they go ; but after all 

 it is merely hypothesis, and rests upon no experimental proof 

 whatever; and I neither have faith in it myself, nor recommend 

 it as worthy of credence by others. A more legitimate sub- 

 ject of speculation than the mode in which the oxalate of am- 

 monia found in guano is produced, is the origin of guano itself 

 and of its varieties. The large lumps found in the bags of 

 guano, which I have termed "concrete guano," appear to 

 me to have been taken from the oldest portions of the beds of 

 this substance, and in which decay of the organic salts and ani- 

 mal substances has proceeded further than in common guano, 

 and that concrete guano is merely ordinary guano in an ad- 

 vanced stage of decay agglomerated by pressure and long con- 

 tact. This remark applies chiefly to sample No. 5. I consider 

 it probable that samples 6 and 7 are formed from the action 

 of sea water on a bed of guano somewhat deficient in ammonia 

 salts and containing no urate of ammonia; in short, one of 

 the oldest beds on the lower ledges of the coast and rocks. 

 The spray of the sea falling upon a bed of guano in this posi- 

 tion mixes with it, the insoluble portions subside in regular 

 horizontal strata, which again dries and hardens, giving rise 

 to the formation of masses consisting chiefly of insoluble sub- 

 stances, as in the specimen No. 6, whilst the solution collect- 

 ing in the crevices and hollows is subsequently dried by eva- 

 poration in a dry atmosphere, and forms the saline guano. 

 No. 7, in which common salt so greatly predominates, the 

 oxalate of ammonia being converted by double decomposition 

 into oxalate of soda and muriate of ammonia; the tlisappear- 

 ance of the larger portion of the latter salt I can only account 

 for by its well-known tendenc}', when in a damp state, as ex- 

 isting as a saturated solution, to creep over the sides of the 

 vessels which contain it, by which means it may have sepa- 

 rated itself from the sea-water solution previously alluded to 

 before that became quite solid and dry, and thus extending 

 itself over the ledges of rock, assisted in its progress by noc- 



