Steam-digging Machine . 297 
and it is well worth the examination of men of invention: 
but two points are easily determined respecting the spade ; 
1st, that it is the most effective implement at present 
known ; and 2ndly, that it is exceedingly well adapted to 
steam power. This I think is clearly shown in the pre¬ 
sent machine : the main point was to convert a rotatory 
motion into that used in digging by a simple arrange¬ 
ment. This has been accomplished by fixing the upper 
end of the diggers to cranks in an axle, and passing their 
handle through holes in the frame of the machine, by 
which they are guided. As the cranks of the axle revolve, 
they alternately raise and depress the diggers, penetrating 
the earth, breaking oft’ a portion, and throwing it out of 
the trench, nearly in the same way that a spade is worked 
by a man. A man, however, after breaking off the 
portion of earth, reverses the soil, that is, brings the 
under part to the surface by turning the spade over late¬ 
rally : this the engine docs not effect; but it is intended 
to accomplish the same end by working it with such a 
speed that it will throw the earth with some violence out 
of the trench, and thereby as effectually reverse the soil 
as by digging by hand. This, however, remains to be 
proved: the machine has yet been tried only by hand, 
and, consequently, at a slow speed; and it appears to 
work perfectly well, as far as respects breaking up the 
soil, and laying it light and even. While the steam is 
working the main axle which carries the diggers, it at 
the same time gives motion to another set of wheels, 
which are connected with the axle of the carriage wheels, 
and give the whole machine a slow retiring motion, so 
that it recedes a few inches during every stroke of the 
diggers. By a simple arrangement of these wheels, the 
motion may be made quicker or slower, according to the 
object in view in digging the land. If it is required to 
exterminate the weeds by cutting them to pieces, or to 
