Steam Culture. 
433 
You lately suggested that a charge of 11. lOs. per day would probably 
bo sxilUcieiit to cover tlio cost of iutci'e.st, repairs, and depreciation 
of machinery and tackle. I am willing to adopt this estimate, 
which, when added to the day's expenses (1/. 26'. 9ci.), gives as the 
total cost of ploughing 5 acres 21. Vis. 9c/., being a charge of (say) 
10*-. Gc/. an acre for steam-ploughing; and since wo can in a day 
cultivate (scuffle) double the quantity ploughed, the cost of culti- 
vating may bo considered as one-half, or bs. 'M. an acre. 
About hero in ordinary ploughing four horses are used in a team. 
They get over on an average three-quarters of an acre in a day, and 
it is reckoned that the cost of ploughing an acre may be put at 20*-. 
According to my showing, the cost therefore of sfeam-ploughing is 
10s. M. an acre, against Aorse-ploughing at 20s. It should be 
remembered, however, that when the plough and tackle are not at 
work the engine is useful in other departments of the faim ; I ought 
not theicfore pi'operly to charge the ploughing, as I have done, with 
the whole cost of the interest and wear and tear of the engine. 
The advantage of employing steam-power on heavy land is not 
confined to a reduced expenditure in cultivation, and to increasing 
the depth of tillage, but by accomplishing so large a daily acreage 
you are less liable (than in the slower process of ordinary ploughing) 
to stoppages in consequence of changes in the weather ; and by 
keeping off your land the heavy treading of horses, that consolida- 
tion is avoided which is so injurious to crops on our stiff clays. 
Then, again, the diminution in the number of horses stabled is a 
great source of economy. Mr. Morton calculates that a working 
horse cannot be kept at a less cost than 30/. a-year ; and this agrees 
with my experience altogether. When I commenced steam- 
ploughing I had in my stable twenty woiking horses : I have now 
ten : that is, my stable expenditure is reduced by one-half. Wishing 
that I were able to reply more fully to your queries, 
I remain, my dear Sir, yours very truly, 
Ed. Holland. 
P. II Frere, Esq. 
XXIII. — On the Composition of Oxen, Sheep, and Pigs, and of 
their Increase xohilst Fattening. By J. B. Lawes, Esq., F.R.S., 
F.C.S., and Dr. J. H. Gilbert, F.R.S., F.C.S. 
More than ten years ago we commenced a series of articles in 
this Journal, the expressed object of which was to elucidate the 
chemistry ot the feeding of animals, considered as a process for 
the manufacture of meat and mamire — and, as such, constituting 
a highly important branch of the business of the farmer. It was 
proposed to investigate experimentally — 
1. The amount of food, or of its several constituents, consumed 
— in relation to a given weight of animal within a given time. 
