418 
Steam Culture. 
per acre, and crossed for 5s. 9^^. per acre, or the double process 
accomplished for 15s. per acre at a depth which will vary from 
7 inches on clays to 12 on loams. 
On the Cost of House-power for Ploughing and 
Scarifying. 
We have now to consider what the same work would cost, if 
done by horses. It had been designed that the general economy 
of horse-power should have been discussed in a separate article 
in this Journal, its importance demanding a distinct notice ; but 
as this intention has not been carried out, I must touch on the 
subject, confining myself, however, to that portion of it which is 
essential to our present purpose. This will be more safe than to 
adopt the broader conclusions of a general statement ; for, at the 
best, agricultural generalizations are so rude, that it is not often 
desirable to supersede special investigation by the assumption of 
a formula. 
In our case there is to be considered the cost and efficiency not 
of the average horse at average work, on the average of the year, 
but of the stout horse adapted to clay land, only when ploughing 
or cultivating, and at those seasons in spring and autumn when 
the demand for horse labour, and consequently its value, are far 
above the average. Now the heavier clay horse costs rather more 
to buy, and a good deal more to keep than that adapted to light 
soils ; there is some ground also for doubting whether his traction 
power in a plough does not considerably exceed that assigned to 
Lim by theory, although that theory, we are told, was based by 
Stevenson on the performances of heavy London horses.* 
• Mr. Morton has shown that 33,000 Ihs., lifted one foot per minute, is equi- 
valent to a draught of 150 lbs. where the horse is working a plough at the rate of 
2j miles per hour. Now, at Canterbury the average draught on the lightest four- 
horse plough was over 800 ll)s., or 200 lbs per liorse. Were, then, the horses 
going at a less rate than 2^ miles per hour ? At a subsequent private trial, three 
horses with an iron plough competed with these four-horse Kentish ploughs. Did 
not these three exert a force considerably in excess of our theory ? 
In Mr. Morton's calculations so much depends upon the number of pounds 
lifted 1 foot high per minute which is equivalent to the average efficiency of the 
horse, that it becomes important that one arithmetical mistake in his Article 
(Journal, vol. xix., p. 4C4) should be corrected. 
The annual horse-labour on Whitfield Farm, says Mr. Morton, amounted to 
37,10G cwt. drawn (= lifted) 1 mile per annum; and he continues, " l''<>r the 
words ' per annum ' we may substitute 300 days of 9 liours each, and the work done 
will be found on calculation to have been equal to the lift of 13.'),4.'j0 lbs. 1 foot 
high per minute during all that time, which, its 7 horses u-cre cmpluyid, was 
16,492 lbs. a-piece." Now 135,450 lbs. (the correct aggregate) divided by 7 gives, 
not 16,492 lbs. as there stated, but ['J,:iM lbs., that is to say, a larger amount than 
that given elsewhere in round numbers as the maximum that was known in one 
instance only (Mr, Melvin's) where tlie cartage was clearly excessive. 
If in the Whitfield schedule some of the work, such as root-carting, is set at a 
high estimate, on the otlier hand on every farm the horses have to perforin a 
certain amount of what may be called estate-labour, in carting materials for roads 
