THE FARMERS' REGISTER. 



59 



The next analysis was by Foiircroy and Vau- 

 quelin (Gehlen's Jour,, vi. p. 679.) Their results 

 gave — 



Per cpiit 



Drale of ammonia ... 90 



Oxalate ol" ammonia - • - 10.6 



Oxalate of lime - ... 70 



Phosphate of ammonia ... 60 



Phosphate of ammoira and magnesia 2.6 



Sulphate of potash ... 5.5 



Sulphate of soda . . . . 3. .3 



Sal ammoniac - - - - 4.2 



Phosphate of lime ... - 14.3 



Clay and sand - - - - 4.7 



Water and orfjanic matters - - 32.3 



100 

 If we suppose the analyses equally correct, the 

 specimens examined severally by Klaprolh and 

 by Vauquelin differed very much in chemical 

 constituiion. That of Klaprolh was mixed also 

 with one-third of its weight of sand and silica. 



To a circular, recently issued by Mr. Macdo- 

 nald, the following analysis is appended, but the 

 authority is not given : — 



Per cent. 



Bone earth 30^ 



Sulphates and muriates - . - 3 



Uric acid . - ... 15 



Ammonia - - ... 15 



Other organic matter ... 36J 



100 



This also differs materially from the other two ; 

 and, allowing for slight errors in analysis, shows 

 that the substance varies widely in composition. 

 It cannot lail, indeed, to vary to some extent, ac- 

 cording to the state of decay in which it is sub- 

 jected 10 examination, 



Oi the guano which has been imported into 

 this country a box having been obligingly sent to 

 me by Mr. Macdonald of the average quality of 

 that which, as he states, is likely to be hereafter 

 brought to England, I have submitted it to a 

 chemical examination, in reference chiefly to its 

 economical value. It is of a brownish-red color, 

 is evidently a very ancient deposite, and has un- 

 dergone much decomposition. It consists of a 

 powdery portion mixed with lumps of various 

 eizes. The latter, when broken, exhibit an ag- 

 gregation of minute crystalline plates, are much 

 richer in ammonia than that which is in powder, 

 and are freer from sand and stones. When broken 

 up, however, the lumps speedily lose their crys- 

 talline appearance, give off ammonia even at the 

 ordinary temperature of the atmosphere, and as- 

 sume the condition of the powdery portion with 

 which Ihey are mixed. 



1. The quantity of sand conta'med \n a portion 

 of the powdery variety I (bund to amount to near- 

 ly 11 per cent. ; while in one lump there were 

 present 8 per cent., and in another less than 2 per 

 cent. The eand consisted chiefly of mica, quartz, 

 and felspar, the debris of the igneous rocks of the 

 coast of Peru. Occasional fragments of rock 

 occur, of considerable eize also, among the 

 guano. 



2. The quantity of volatile or combustible mat- 

 ters, (including the water and ammoniacal salts) 

 which are capable of being driven or burned off by 

 .a red heat is also very variable. Thus, 4 portions, 



taken at random from different pans of the box, 

 lost, respectively, 23^, 46, 60, and 53 per cent, of 

 iheir whole weight ; leaving an ash of a white 

 or slightly gray color. This difference is not 

 owing to the presence of unlike quantities ofsand, 

 lor the numbers above given are calculated on the 

 supposition that the specimens were all free from 

 s.iiid. Thus the first specimen lost by heating 

 only 21^ ; but, as it contained 8 per cent, of sand, 

 it wouliJ have lost, as stated^above, if free from 

 sand, 23^ per cent. 



In so /ar as the volatile constituents are con- 

 cerned, llierefore, the guano which comes to this 

 country may vary in value from 1 to 3. 



3. Yet the loss by heating, which is very easily 

 ascertained, is not a true measure of the richness 

 of the guano in ammonia and other valuable or- 

 ganic matters. When reduced to powder it ra- 

 pidly absorbs moisture from the air. Thus, in 

 48 hours, a weighed portion of a lump broken 

 into coarse powder gained by exposure to the air 

 2 per cent. ; another portion gained in 10 days 

 no less than 6 per cent., and after a longer lime it 

 became perceptibly moist between the fingers. 

 This absorption of water from the air will lend 

 not only to depreciate tlie value of a given weight 

 of the guano when brought to our humid climate, 

 t)ut also to cause errors in the results of agricul- 

 tural experiments made with different samples 

 of the manure. 



4. I have stated above that the lump guano 

 when crushed gives off ammonia at the ordinary 

 temperature of the atmosphere. In hot weather 

 this may be rendered sensible by holding over it 

 a feather dipped in strong vinegar or diluted mu- 

 riatic acid ("spirit of salt.) when white fumes will 

 be perceived ; or at any time by healing the guano 

 to lOO'^ or 150*^. By this evolution of ammonia 

 it loses both in weight and in virtue. By drying 

 at 150° I Ibund a lump to lose 11 per cent, of its 

 weight, ammonia being sensibly given ofi' during 

 the whole duration of the experiment ; yet when 

 it was again exposed to the air it absorbed so 

 much water as in four days to be 5 per cent, 

 heavier than it had been before it was exposed 

 to heat.* 



This evolution of its volatile constituents by 

 exposure to the air is well known on the coast of 

 Peru. From the guano island near Aricasucli 

 a stench proceeds that vessels are prevented by it 

 from ancfioring near the town (Feuille and Hum- 

 boldt;) while the white guano at the present day 

 sells in the port of Mollendo at a price more thaa 

 one half higher than that which is given for the 

 dark-gray and the red. (Winterfeldi.) 



I do not know in what way the guano is shipped 

 for transport to this country ; but it is certain that 

 were it rammed hard into casks as soon as it is 

 taken from the mine, and so kept in this country 

 till it was about to be applied to the land, it would 

 neither be so far deteriorated by the loss of its 

 volatile constituents, nor increased in weight by 

 the absorption of water. 



5. The absolute quantity of ammonia contained 

 in the guano of Klaprolh and Vauquelin is not 

 Slated. In the analysis published by Mr. Mac- 



• If a little guano powder be mixed in a wine-glass 

 with a little newly-slaked lime, ammonia is imms- 

 diately evolved, and becomes distinctly sensible te 

 the smell. 



