In using the corn planter, a wire, having buttons attached thereto, at intervals corresponding to the distance between the hills, is first stretched across the field and anchored at its ends. This wire is then placed upon the guide rollers at the side of the machine and passes between the jaws of a forked lever, which is connected at its other end with a rocking shaft passing across the machine and serving to oscillate a feed-plate in the bottom of each seed-hopper. As the buttons on the check-wire strike the forked lever, the latter is drawn to the rear and causes the feed plate to drop the seed through the tubes into the open space between the plates of the furrowing shoe. A reel at the rear of the machine is used to take up the check-wire as the planter progresses. (P. WC.) SOYBEAN, also known in some countries as the soja bean ond the soya bean, is a leguminous plant native to south eastern Asia. It has been cultivated in China and Japan since long before written records were kept, and from the standpoint of uses and value is the most important legume now grown in those countries. Although limited acreages are grown in Italy, France, southern Russia, Rumania, Netherlands Indies, South Africa and in a few countries of South America, its culture at present is largely confined to China, Manchuria, Japan, Chosen (Korea) and the United States. It is also more or less important in India, Indo China and the Malayan islands. Although first introduced into the United States in 1804, the soybean has become important only during the last 20 years. Only 8 varieties were grown in 1898, whereas at present more than loo varieties are handled by growers and seedsmen. Previous to 1917, the soybean acreage was less
than 5oo,000, but by 1939 it had increased to more than 8,000.000.
The soybean can be grown in any climate suitable to maize or cot ton, and the crop is now grown generally over the eastern half of the United States. Recent increases in acreage have been most marked in the maize belt and some of the Southern States. Intro duction and breeding of improved varieties have extended the cul ture of the crop far beyond what were first considered its limits of profitable production, and it is destined to become a crop of great economic importance in the United States. Its principal uses are hay, pasture, silage, oil and oil meal, and human food (see SOYBEAN OIL). It can be used advantageously, either as a seed crop or a forage crop, in many systems of rotation; also as a catch crop where new seedings of grass or clover have failed. In combi nations with other crops, such as corn, cow-peas, Sudan grass or sorghums, it furnishes a well-balanced ration for livestock, a large yield and a great variety of forage.