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XXXII. — Agricultural Chemktry. — Pig Feeding, By 

 J. B. Lawes, of Rothamsted. 



In a former Number of this Journal we published a paper under 

 the title of ' Sheej) Feeding and Manure^ in which we gave the 

 amount of Increase in Live iceight of Animal, obtained by the 

 consumption of known quantities of food of various kinds — the 

 chemical composition of such food being* also given — and we 

 promised to follow up the subject in our next with an account, 

 first, of the Composition of the Increase in Live iceight, and after- 

 wards, of that of the Manure obtained. The main object, indeed, 

 of the investigation — as stated both at the commencement and 

 conclusion of that paper — was, to illustrate the general economy 

 of the feeding process, as one of the great features of farming 

 practice ; that is to say, as producing Manure as well as Meat, 

 rather than as comparing one food with another in regard to its 

 feeding value merely. 



Sheep had at that time received the greatest share of our 

 attention ; and, owing to the difficulty and labour involved in ex- 

 tending the field of experiment in like detail to other animals, it 

 was intended, if possible, to complete our subject of Meat and 

 Manure-making by almost exclusive reference to the animals 

 which had given the title to our paper. The further we pro- 

 gressed, however, the more were we convinced, that in spite of 

 the difficulties and necessary postponement of publication, the 

 inquiry must be extended to other animals, to enable us at all 

 satisfactorily to explain the connection between the composition 

 of the food consumed by farm stock generally, and that of the 

 increase, and manure, obtained. 



Viewing the feeding process as one of the chief means of obtain- 

 ing manure, it is of the utmost importance that the farmer should 

 be possessed of some principles by which to judge of the produc- 

 tive power of such manure, especially in relation to the compo- 

 sition and value of the food consumed. And, as in this country 

 there is employed a constantly increasing amount both of pur- 

 chased and saleable food, and of artificial manures, it is essential 

 that the farmer should possess a clearer conception of the prin- 

 ciples both of Feeding and of Manuring. 



The importance of such general propositions in agriculture 

 cannot be over-estimated ; nor will they be undervalued when 

 farmers more clearly recognise and appreciate the influence of 

 chemical composition in determining the value of manure, and 

 how far it is a question merely of economy, whether tlie fertility 

 of the soil shall be kept up by manures produced in the yard 

 and the stall, or by those which are purchased in the market. 



