212 MANURE, ARTIFICIAL 



the formation of humic acids, and similar organic compounds. These organic acids 

 constitute the mixture of organic matters, -which in practice pass under the name of 

 humus. 



Composition of Farmyard Batted Dung (Horses', Cows', and Pigs'), in 100 parts. 



Water 75'42 . 



Soluble organic matter ' 371 



Soluble inorganic matter (ash) : 



Soluble silica 254 



Thosphate of lime -382 



Lime -117 



Magnesia , -047 



Potash 446 



Soda -023 



Chloride of sodium -037 



Sulphuric acid -058 



Carbonic acid and loss -106 



1-47 



Insoluble organic matter - 12-82 



Insoluble inorganic matter (ash) : 



Soluble silica 1'424 



Insoluble silica 1-010 



Oxides of iron and alumina, -with phosphates . -947 



Containing phosphoric acid . . . " . . (-274) 



Equal to bone-earth ('573) 



Lime 1-067 



Magnesia -091 



Potash '. -045 



Soda . . -038 



Sulphuric acid . -063 



Carbonic acid and loss 1-295 



6-58 



100-00 



Farmyard manure thus is a perfect manure, for experience and analysis alike 

 show that it contains all the fertilising constituents required by plants, in states of 

 combination which appear to be especially favourable to the luxuriant growth of our 

 crops. 



On most farms the supply of common yard manure is inadequate to meet the de- 

 mands of the modern system of high farming. Hence the endeavour of enterprising 

 men to supply this deficiency by converting various refuse materials into substitutes 

 for farmyard manure. Artificial manures likely to approach farnyard manure in 

 their action should contain all the elements in the latter, and in a state of combina- 

 tion, in which they are neither too soluble nor too insoluble ; for it is evident that a 

 plant can grow luxuriantly, and come to perfect maturity only when all the elements 

 necessary for its existence are presented to it in a state in which they can be assimi- 

 lated by the plant. 



But the question arises, Is it desirable to produce by art perfect substitutes for 

 common dung ? We think not, for the following reasons : 



In the first place, well-rotted dung contains in round numbers two-thirds of its 

 weight of water, and only one-third of its weight of dry matter. A large bulk there- 

 fore contains, comparatively speaking, but a small proportion of fertilising-matters. 

 In every 3 tons of manure we have to pay carriage for 2 tons of water ; and it may 

 bo safely asserted that no manure, however efficacious it may be in a dry condition, 

 will be found an economic substitute for farmyard manure, if it cannot be produced in 

 a much drier condition than common yard manure. 



Again, several of the constituents which greatly preponderate in farmyard manure 

 are present in most soils in abundant quantities ; they need not, therefore, be supplied 

 to the land in the form of manure ; or, should they be wanting in the soil, they can 

 be readily obtained almost everywhere at a cheap rate. If, therefore, these inexpen- 



1 Containing nitrogen I -297 



Equal to ammonia . *S6 



* Containing nitrogen '309 



Equal to ammonia -375 



Whole manure containing ammonia in free state . . . -046 



,, form of salts . . -007 



