All About Inventions and Discoveries
The Romance of modern scientific and mechanical Achievements

264 All About Inventions dispensable element through its leaves in a manner comparable with our process of respiration, because the plants are unable to select the nitrogen from the air. This staff of life has to be associated with the soil, so that it may be sucked up by the roots of the plant. Fortunately for the vegetable kingdom, it is not a difficult matter to administer the nitrogen in this manner, because all fertilisers, both natural and artificial, possess a certain proportion of nitrogen, although the content of this element varies widely, according to the nature of the agent. All decaying matter, both vegetable and animal, contributes a certain proportion of nitrogen, which explains why such refuse is turned into the ground for the stimula- tion of plant life. But the needs of the community have grown so rapidly and enormously that what may be described as natural fertilisation has become inadequate. There is one plant more than any other upon which we depend vitally, and consequently it is necessary for us to stimulate this plant to an excessive degree—to force it, as it were, so that its yield shall be twice or thrice of what it would be if left to Nature. The plant in question is wheat. It has been known since the earliest days as the “ staff of life,” and never was this colloquialism more true than it is to-day. And yet we are virtually fighting for our existence. The population of the world has multiplied at such a rapid rate as to produce a critical situation, because the yield of wheat is not rising in proportion. The whole of the white race, and an increasing number of other races which have been and are being brought into contact with the white men,