COMPOUND MANUEES. 143 



the inverse order, that is to say, by lifting it from the ground to 

 throw on to the middle of the heap. ^ 



These manipulations are sometimes rather unpleasant, such as 

 the disengagement of dust, etc., nevertheless they form the best 

 method of mixing. The materials so mixed are afterwards passed 

 through a Carr's disintegrator or through the toothed crusher and 

 a very homogeneous mixture is thus obtained. Inert materials 

 should be avoided in these mixings. By mixing high strength 

 superphosphates with low strength superphosphates common sorts 

 can be made without recourse to inert materials, sand, plaster, etc. 



[Sujjerplios'pliate of Ammonia ^J Ammoniated Superjjhosphate. — 

 Although the composition of this manure is very variable, the most 

 usual strength being 9 x 9, 5 x 10, or 6 x 12, the first figure in- 

 dicating the percentage of nitrogen, the second the percentage of 

 soluble phosphoric acid, this manure is in great esteem. It is 

 analogous to dissolved Peruvian guano to which farmers are 

 accustomed. It, moreover, presents this advantage, that its acid 

 retrogrades less easily in the soil than that of pure superphosphate, 

 seeing that the sulphuric acid combines first with the bases which 

 it encounters in arable land. The mixture of superphosphate with 

 sulphate of ammonia is easily made. Sulphate of ammonia is 

 delivered in a finely ground granular condition. It contains 24*5 per 



1 This explanation is not very intelligible ; possibly the following will make 

 it plainer : — 



Take a 10 ton mixing according to the following formula : — 



'Tons. Cicts. 

 15 cwt. superphosphate . . . . . . = 7 10 



3 cwt. sulphate of ammonia =1 10 



1 cwt. bone meal .......= 10 



1 cwt. muriate of potash .....= 10 



First ot all the 7^ tons of superphosphate would be laid down in a heap and 

 accurately levelled, then the IJ tons of sulphate of ammonia would be spread 

 uniformly over the levelled top of the heap, then the J ton of bone meal uni- 

 formly over that, then the muriate over that. Then a screen with two men 

 would be placed at one end of it and a man to get the stuff for them, that is by 

 digging down the heap vertically and mixing it for the two men to shovel it 

 through a ^ inch or 1 inch screen. When this first screening is done the 

 material is screened through in the reverse direction, but this time through 

 a I inch sieve. If the heap has been laid down anything like proportionately 

 and uniformly, samples taken from any point will agree in analysis in a manner 

 that those who have not seen it done would hardly credit. If the 7 J tons of 

 superphosphate were taken from the superphosphate heap, if the foreman has 

 a good eye for bulk and weight there need be no necessity to weigh the 7^ tons ; 

 he can tell to a nicety its bulk. — Tb. 



2 This name as used by the author is misleading, applied as it is to 

 a mere mechanical mixture of sulphate of ammonia and superphosphate of lime, 

 and would not pass muster in a court of law in Great Britain. The translator 

 has altered it to ammoniated superphosphate. Superphosphate of ammonia 

 seems to imply that it is a superphosphate of lime in which the lime is replaced 

 by ammonia. But that does not occur until the manure is dissolved by the 

 moisture in the soil. — Te. 



