go on a strike.  The farmer, not seeing the thing from the standpoint of the bacteria, says the soil is “sick” and he proceeds to doctor it according to his own notion of what ails it.  First perhaps he tries running in strike breakers.  He goes to one of the firms that makes a business of supplying nitrogen-fixing bacteria from the scabs or nodules of the clover roots and scatters these colonies over the field.  But if the living conditions remain bad the newcomers will soon quit work too and the farmer loses his money.  If he is wise, then, he will remedy the conditions, putting a better ventilation system in his soil perhaps or neutralizing the sourness by means of lime or killing off the ameboid banditti that prey upon the peaceful bacteria engaged in the nitrogen industry.  It is not an easy job that the farmer has in keeping billions of billions of subterranean servants contented and working together, but if he does not succeed at this he wastes his seed and labor.

The layman regards the soil as a platform or anchoring place on which to set plants.  He measures its value by its superficial area without considering its contents, which is as absurd as to estimate a man’s wealth by the size of his safe.  The difference in point of view is well illustrated by the old story of the city chap who was showing his farmer uncle the sights of New York.  When he took him to Central Park he tried to astonish him by saying “This land is worth $500,000 an acre.”  The old farmer dug his toe into the ground, kicked out a clod, broke it open, looked at it, spit on it and squeezed it in his hand and then said, “Don’t you believe it; ’tain’t worth ten dollars an acre.  Mighty poor soil I call it.”  Both were right.

[Illustration:  Courtesy of American Cyanamid Co.

FIXING NITROGEN BY CALCIUM CARBIDE

A view of the oven room in the plant of the American Cyanamid Company.  The steel cylinders standing in the background are packed with the carbide and then put into the ovens sunk in the floor.  When these are heated internally by electricity to 2000 degrees Fahrenheit pure nitrogen is let in and absorbed by the carbide, making cyanamid, which may be used as a fertilizer or for ammonia.]

[Illustration:  Photo by International Film Service

A BARROW FULL OF POTASH SALTS EXTRACTED FROM SIX TONS OF GREEN KELP BY
THE GOVERNMENT CHEMISTS]

[Illustration:  NATURE’S SILENT METHOD OF NITROGEN FIXATION

The nodules on the vetch roots contain colonies of bacteria which have the power of taking the free nitrogen out of the air and putting it in compounds suitable for plant food.]

The modern agriculturist realizes that the soil is a laboratory for the production of plant food and he ordinarily takes more pains to provide a balanced ration for it than he does for his family.  Of course the necessity of feeding the soil has been known ever since man began to settle down and the ancient methods of maintaining its fertility, though discovered accidentally and followed blindly, were sound and efficacious.  Virgil, who like Liberty Hyde Bailey was fond of publishing agricultural bulletins in poetry, wrote two thousand years ago: