A drawing by Trevithick—having as usual neither name, date, nor scale, nor writing of any kind, but the watermark in the paper is 1813—illustrates his ideas expressed to Sir Charles Sinclair in 1812:—"It is my opinion that every part of agriculture might be performed by steam." The thrashing and grinding engines were at work, and the tormenting harrowing engine was probably designed for bringing under steam cultivation the extensive commons referred to. In those days, before the practice of underground drainage, the surface of cultivated land was thrown into furrows, or a series of small hills and vales, the latter acting as the surface drain for carrying off the water.
Suppose the first step in cultivating a common to be the breaking of the soil, and throwing it into uniform lines of rise and fall that facilitated drainage without inconveniencing the tillage, what better machine could have been devised than Trevithick's? A combination of the modern tormentor and harrow loosened the ground to the required depth, which was then, by a revolving wheel with spades, thrown on one side, resulting in uniform lines of ridges and hollows. The steam-shoveller was removed, or the tormentor irons raised, when only the harrow was required.
The absence of the ordinary shafts at the front end of the framing indicates that the spade-tormentor was not to be drawn by horses, but whether by a locomotive or by a fixed engine is not self-evident.
Trevithick's Steam Spade-tormentor, 1813.
[Rough draft.]
"Camborne, January 26th, 1813.
"Mr. Kendal,