286 CHEMICAL MANUEES. 



of the phosphoric acid, moreover, depends on the percentage of 

 alkaline salts in the guano, present-day raw guanos are much less 

 soluble than the old Chincha guanos. Farmers were, therefore, 

 justified up to a certain point in attributing to the old guanos now 

 exhausted a characteristic specific action, not only because these 

 guanos contained 12 per cent of nitrogen against 7 per cent in the 

 present products, but also because the ammoniacal salts present 

 are insufficient to bring the phosphoric acid to a soluble condition 

 in the soil. 



By now using 100 lb. of raw guano with 7 per cent of nitrogen 

 and 14 per cent of phosphoric acid, the same results would be 

 obtained as formerly with 58 lb. of the old guano (containing 12 

 per cent of nitrogen and 12 per cent of phosphoric acid), mixed 

 with 20 lb. of 36 per cent phosphoric acid and bone ash. It 

 follows that the use of raw guano in these circumstances would be 

 sheer waste of phosphoric acid. Taking it for granted that all the 

 phosphoric acid of the old guano was soluble in the soil (which is 

 •not absolutely demonstrated), it may be asserted with certainty that 

 •only the half of the phosphoric acid is soluble in the guano of the 

 present day. Now by dissolving the guano the farmer can utilize 

 all the phosphoric acid present in the manure. Another advantage 

 which dissolved guano has over raw guano, is that its nitrogen 

 cannot be volatilized nor consequently lose its nitrogen in the air. 

 All the carbonate of ammonia is converted into sulphate, and if 

 new portions could be formed it would at once be fixed by the 

 sulphuric acid. 



Finally, dissolved guano is more easily applied than raw guano ; 

 it contains neither lumps, which oblige the farmer to crush it, nor 

 dry powder, which, spread in stormy weather, lost itself in the 

 neighbouring field. Dissolved guano is in the form of a moist but 

 not tacky powder. The farmer has so well understood these ad- 

 vantages, that he has given up the use of raw guano. ^ 



1 The farmer has no option but to give up what is not available. \Yhen 

 the old guano was applied to gi'ain crops at the time of sowing it was appUed 

 broadcast, and in the north-east of Scotland by an experienced man who dis- 

 tributed it with both hands, swinging them rhythmically, and alternately throw- 

 ing to the left with his right hand and to the right with his left hand, in a 

 manner to be seen to be appreciated. If these farmers could get the old guano 

 back again they would soon find means of applying it. In former days the bags 

 were distributed over the field, and the requisite amount carried by women on 

 their heads, in a wide sieve-shaped vessel with a leather bottom, to the man sowing 

 it, the whole forming a picturesque scene when the man distributing the manure 

 had the knack of s'winginghis two hands almost simultaneously and in opposite 

 direction. Grain was sown in the same way. If the guano burned the cloihes 

 and got in the eyes that only showed its virtue. Now the fanner only gets the 

 dead body, whose spirit, volatile ammonia, has departed. The sulphuric acid has 

 killed it by fixing it, even if it has dissolved the phosphates ; besides it must be 

 remembered that the sulphuric acid used to dissolve it only costs £2 per ton at 

 the most, and that the cost of the guano to the concessionaires is diminished 

 ^ro rata. — Tk. 



