A CHAPTER ON GUANO. 357 



Tlie young analyst could not, however, proceed with sufficient 

 accuracy from directions so general, and which are deficient 

 in all the details of manipulation. Yet, general as it may be, 

 it comprises ample comparisons of results as obtained by 

 various eminent chemists, all tending to show what every one 

 who undertakes an analysis of this substance must soon dis- 

 cover, that there are no two samples of guano which perfectly 

 agree in their constituents. 



Dr. Ure gives — first, the tabular catalogue of the consti- 

 tuents found by the French chemists in the sample presented 

 by Humboldt," estimated in hundredth parts and decimals. 

 We assume the grain of apothecaries' weight, as being the 

 simplest integer, and thus in 100 grs. are found — 



Urate of ammonia 9.0 



Oxalate of ammonia 10.6 



Oxalate of lime 7.0 



Phosphate of ammonia 6.0 



Phosphates of ammonia and magnesia . 2.6 



Sulphate of potash 5.5 



„ of soda 3.3 



Sal-ammoniac 4.2 



Phosphate of lime 14.3 



Clay and sand 4.7 



Clay and organic matters .... . 32.3 



Loss 5 



~lMo 



This might be reckoned as a fair sample of fertilising guano ; 

 but the last named items, 32.3, are loosely given, because 

 they do not particularise the proportion of water and organic 

 matters. 



The analysis of Professor Johnston is far less satisfactory. 

 Thus— 



Ammonia 7.0 



Uric acid 0.8 



Water, carbonic acid, and oxalic acids, | p^-. p^ 



&c. expelled by a red heat . . . j 

 Common salt, -with a little sulphate \ -. -. i 

 and phosphate of soda . . . . j 



Phosphate of lime, &c 29.3 



100.0 



