"It is also necessary to vary the strength of the current during the day. With full sunshine and maximum heat we do not need as much current as we use during the night. Several hundred years ago when using somewhat similar methods that had not as yet been perfected, it was necessary to use artificial light during the night, as plants need light for growth. We found, however, that the electric current with the soft light which you see glowing now, is sufficient for the purpose and the plant does not require any other light." Alice stood for many minutes silently watching the beautiful sight of the glowing purple field, listening to the faint crackling discharge of the electric current as it leaped from the points of the wheat into the air. They finally left and flew back to New York. The next day, Ralph took Alice to one of the city's Synthetic Food Laboratories. While flying toward it, Ralph explained that while the farms which they had looked over yesterday were for the purpose of raising real foodstuffs, there were many commodities that could not be so raised, such as sugar, milk, and many others, which were now made synthetically. As chemists had known for many hundreds of years, sugar was nothing but a simple carbohydrate, whereas milk was composed of an emulsified mixture of casein, lactic acid, butter, water and minor constituents. As the population increased, it was neither possible, nor profitable to obtain these foods by natural means, and it was found necessary to resort to the chemist. They alighted at one of these chemical laboratories which manufactured sugar, milk, cooking fats, butter and cheese. There was really not much to see, save large boiler-like chemical retorts, large white enameled vats, and a lot of pumps and electric motors. The manager explained that sugar was made out of sawdust and acids. The sawdust, he explained, was digested in the huge white enameled steel vats by means of certain acids. After the digesting process was completed other chemicals were added, the ensuing syrup then being run through retorts and finally emerging as a stream of white liquid sugar. The manager handed Alice a piece of clear, transparent sugar, as well as several specimens of crystallized sugar, which she ate delightedly, exclaiming laughingly that "it was the best sawdust she had ever eaten." They next visited the synthetic milk section, where hundreds of thousands of gallons of milk were produced every day. This being a recent discovery the manager explained it in detail. "Milk," he said, "has been known since the dawn of humanity, but only when man became somewhat civilized did he learn how to obtain milk from animals, such as the goat and the cow. It took thousands of years to domesticate these animals, and it is not known at what period man first began to milk these domestic animals for his own supply of milk.