The plow is drawn across the field by means of cables. Sometimes a traction engine moves along with the plow.
But the plow of Jethro Wood, as excellent as it was, did not fully meet the needs of the western farmer. The sod of the vast prairies could not be broken fast enough with a plow of a single share. So about the middle of the nineteenth century the gang plow, a hint for which had been given long before (p. 78) was invented, and as this new plow moved along three or four or five furrows were turned at once. At first the gang plow was drawn by horses (Fig. 13) but later it was drawn by steam (Fig. 14).
The great gang plow drawn by steam marked the last step in the development of the plow. The forked stick drawn by human hands and making its feeble scratch on the ground had grown until it had become a mighty machine drawn across the field by an unseen force and leaving in its wake a broad belt of deeply-plowed and well-broken soil.
[THE REAPER]
After man had invented his rude plow and had learned how to till the soil and raise the grain, it became necessary for him to learn how to harvest his crop, how to gather the growing grain from the fields. The invention of the plow, therefore, must have soon been followed by the invention of the reaper.