Steam-digging Machine . 299 
hours, would require one man to manage it, and one 
man with a horse and cart to fetch wood and water. It 
is evident that as any machine for breaking up the soil 
must, besides performing that operation, move itself, a 
main point to be attained is that, in digging a certain 
extent, it may move as small a distance as possible; and 
it is equally evident that, in the present machine, so 
considerable a space may be taken at once that the dis¬ 
tance passed over by the engine will be comparatively 
very small. A new apparatus of this kind must neces¬ 
sarily require many trials and new adjustments to bring 
it into quite an effective state; but a pretty good judg¬ 
ment can be formed of the soundness of the principle 
of this machine from an inspection of the one now con¬ 
structed, and from its operation when worked by men. 
The weight of a 5-horse power machine would perhaps 
be 2 tons, and of a 10-horse one under 3 tons; but 
with a regular locomotive boiler it would weigh less. If 
the proposed rotatory engine is used, almost every intel¬ 
ligent ploughman might be taught to manage it. 
The advantages of the machine would be these : 
1st. It would dig an acre in this Island at about 
3s. 67/., including everything, and one digging would be 
equal at least to two plougliings ; while the two plough- 
ings, estimated from the same data, would cost 205. 
2nd. It would require 3 men to a 10-horse machine 
to dig 10 acres per day, which with horses requires 
10 men. 
3rd. The soil might be dug to almost any depth. 
What a farm regularly dug over to the depth of 1 foot 
would produce, it is difficult to judge ; but it can hardly 
be reckoned at less than one-third more than on the 
present system. 
4th. The machine being portable, when it was not 
required to dig, the engine might be employed in sowing, 
grinding, or thrashing. 
