MANURES. 113 



applied to the land in the form of powder. It is sold in this state at 

 8 per ton. 



Bones have been extensively used as a manure during the last forty 

 years. They are used in two ways : they are either hroken up by mills 

 into a rough kind of powder and sold as bone-dust or crushed bones, 

 or they are dissolved in sulphuric acid. The latter is the most imme- 

 diately effective, both as a topdressing for grass and when used for 

 turnips; and this is accounted for by the fact that the different small 

 particles of the bones are more finely separated when the dissolving 

 takes place ; in this way the manure is more efficiently spread over 

 the soil, and gets better about the roots of the plants than several large 

 pieces of bones will do. There is no doubt, also, but that the sulphur 

 in the acid has a beneficial effect, since agricultural chemistry tells us 

 that sulphur is necessary in a small degree to the growth of plants. 

 Dissolved bones are often got in an adulterated state ; when a farmer 

 is not certain about getting them pure, he should prepare them himself. 

 The following description as to the way in which they are prepared is 

 taken from Johnston's ' Elements of Agricultural Chemistry and Geo- 

 logy,' eighth edition, page 216 : 



For the purpose of bringing bones into a state in which the substances they con- 

 tain can be more readily taken up by the roots of plants, and at the same time more 

 uniformly distributed through the soil, the method has been adopted of dissolving 

 them in sulphuric acid. For this purpose, the bone-dust is mixed with one-half its 

 weight, and sometimes with its own weight, of sulphuric acid (the oil of vitriol of 

 the shops), previously diluted with from one to three times its bulk of water. Consider- 

 able effervescence takes place at first, from the action of the acid upon the carbonate 

 of lime in the bones ; but after two or three days, with occasional stirring, the bones 

 are entirely dissolved or reduced. The solution or paste may now be dried up with 

 charcoal powder, with dried or charred peat, with sawdust, or with tine vegetable 

 soil, and applied with the hand or with the drill to the turnip crop ; or it may 

 be diluted with fifty times its bulk of water, and let off into the drills with a water- 

 cart. 



A simple mode of preparing crushed bones for immediate use is to 

 mix them with dry peat-mould, and occasionally water the heap with 

 liquid manure. Fermentation soon sets in, and the bones become dis- 

 solved. A quantity of salt mixed through the heap is of much use. 



Nightsoil is a very strong and useful manure. It is one of the chief 

 manuring substances used by the Chinese, who have taught us many useful 

 lessons in cultivation. It has never been properly used in this country, 

 most probably on account of the difficulty of its application and its smell. 

 The best way to obviate this is to mix it with dried earth or peat, when 

 it can be easily applied to the land. In Paris it is mixed with lime 

 and allowed to dry in the open air, and then put into large stoves to dry 



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