of ammonia 5 x 10. For 100 kg. of mixture, take — ,^^ ^ = 24:'4:. 



COMPOUND MANUEES. 145 



its manner of manufacture, and may end in fifteen days, when the 

 mass is in a large heap and exposed to a certain pressure. " Super- 

 phosphate of ammonia " (ammoniated superphosphate) forms a 

 hard, sometimes locky mass, the shifting of which is expensive, for 

 one is obliged to blow it up wdth gunpowder (! ! ! ).^ It is crushed by 

 Carr's disintegrator, is j^assed through the sieve, and bagged up 

 immediately afterwards, for it does not solidify again if made 

 according to rules, that is to say, if each grain of sulphate of 

 ammonia is united to its grain of superphosphate to form a sulpho- 

 phosphate. To diminish the hardening as much as possible, sand, 

 or better still, powdered peat, sawdust, wool dust (? scutch), or chim- 

 ney soot are added, and in the second place, immediate saturation of: 

 the sulphate of lime by the addition of a little water. The secondil 

 grinding is therefore necessary to effect the perfect mixing of the- 

 two ingredients. In fact, if the substance be analyzed after the first 

 crushing, there w^ill be found 8-8 per cent of phosphoric acid andl 

 9*2 per cent of nitrogen, together 18 per cent, but after the second 

 crushing the product uniformly shows 9 per cent of phosphoric acid 

 and 9 per cent of nitrogen. This method of preparation serves, 

 equally, for all the mixing it is desired to make superphosphate 



100 X 5 



20^ 

 kg. of sulphate of ammonia of 20*5 per cent N, and consequently 



n^r ^ ,■ u i . . • ■ 100 x 10 , .3 ^ 



7o"b kg. of superphosphate contammg — --— — = 13-2 per cent. 



phosphoric acid. If it be a case of a wagon of 10 tons of sulphate- 

 of ammonia, 41 tons of the mixture will be obtained of the 5 x 10' 

 mixture, requiring consequently 31 tons of superphosphate. It is. 

 easy to bring the superphosphate to the right strength by mixing a* 

 high strength superphosphate with a low strength superphosphate- 

 or with gypsum free from iron, alumina, and carbonate of lime, a 

 poor superphosphate with a rich superphosphate, or wdth a double- 

 superphosphate. 



^ In the hardening of the author's so-called superphosphate of am- 

 monia he seeni"^ to confuse mixing operations by the wet w.-.y with those by 

 the dry way. It is perfectly feasible that through bad manipulation a mixing, 

 might so harden in the " dens " that it might almost require blasting operations 

 to break it up, but only through culpable, nay wilful, neglect on the part of the 

 man in charge of the mixer in not running in the proper amount of acid,. 

 Bone meal and sulphate of ammonia give a very hard glutinous mixing when 

 sent up the cups, but sulphate of ammonia and phosphate alone should do no. 

 such thing. The translator has made numerous dry mixings of superphosphate 

 with sulphate of ammonia in all proportions and never found the hardening 

 to go further than caking, but he always made a point of having at least 1 cwt=. 

 to IJ cwts. or even 2 cwts. to the ton of bone meal in such mixings, and this, 

 kept it friable and open, and when the stimulant elements of the manure hacJ. 

 done their work then the plant had something to fall back upon. — Tn. 



10 



