[Footnote 4: At the time this was written, no illuminated, night time sports fields existed.]
[Footnote 5: In 1911 the outer planet Pluto had as yet not been discovered.]
The following day was set aside for a visit to the Accelerated Plant Growing Farms. It had been known for hundreds of years that certain plants, such as mushrooms, could be fully developed in a few days. Plant or vegetables grown under glass and the temperature within kept at a high point, would grow at great speed and be ready for the market long before those grown in the open.
But only recently, as Ralph explained to Alice, had it been possible to do this on a large scale. To be sure, certain vegetables, like asparagus, lettuce, peas, etc., had been produced in hothouses for hundreds of years, but these, after all, were rather luxuries, and could not be classed as essentials.
When, about the year 2600, the population of the planet had increased tremendously and famines due to lack of such essentials as bread and potatoes had broken out in many parts of the world, it was found vitally necessary to produce such necessities on a larger scale and with unfailing regularity. These farms became known under the term of Accelerated Plant Growing Farms and were located in every part of the world. The first (and now obsolete) European and African farms were built along the lines of the old-fashioned hothouses. The European farms were simply horizontal steel-latticed roofs, with ordinary glass panes, permitting the sunlight to penetrate to the soil beneath. While covering huge acreages, they were not heated artificially, using only the sun's rays to accelerate plant growth. As compared with Nature's single crop of wheat or corn, two could be made to grow in the same season by means of these super hothouses.
Similar farms were used in America until Ralph undertook their study and approached the subject from a scientific angle. One of his first efforts was to obtain greater heat for these huge hothouses. One of these hothouses is about three miles long and the same width. Ralph took the existing hothouses, which were simply oblong steel and glass boxes, and built a second hothouse box covering each of them, thus creating a double-walled, air-locked hothouse. The second glass-paneled wall was about two feet inside the outer one. This left dead air locked between the walls, and as air is a poor heat conductor, the heat in the hothouse was retained longer, particularly during a cold night.