“I tell you what we’ll do, Bob,” Billy suggested. “Let’s come home in March and build one!” “Won’t that be grand!” cried the girls with enthusiasm. “We’ll help all we can.” “Ah! You can’t——” began Billy, then stopped. * * * * * So one sunny day in the early part of March, just the very day Eleanor discovered some of the snowdrops blooming, the boys surprised them. About an hour after they came, the lumber and sashes for the hotbed arrived. “We bought the frames ready to set up,” Billy said, “but a fellow could make one quite well. Even a grocery box, if cut in the right shape and covered with glass, makes a good substitute.” “Yes, we made that kind at school for practice,” added Bob, and to show how well he had learned his lesson, he started to dig where they had decided to place the hotbed. Meanwhile Billy referred to his useful note book, and explained what they were about to do. “The situation is very important,” he said, “for we learned at school that a— HOTBED should be sheltered from the north winds; so, if possible, place it on the south side of a large building. Let it slant toward the sunny south, where the glass sash will catch the sun’s rays. You see, a hotbed is a tiny greenhouse. In both a greenhouse and a hotbed, artificial heat is supplied. Greenhouses are heated by steam or hot water pipes: ordinary hotbeds are heated by fresh manure, which, in the process of decomposing, gives off a great amount of heat. Heat, air and sunlight are essential for plants’ growth. The slanting glass sash catches the sunshine, and holds in the heat which the manure gives off. The sashes are raised a little in the warmest part of each day, which gives the plants air. The frame is generally about eighteen inches high in back and twelve inches in front. Dig nearly two feet deep, in a space a foot wider and longer than the frame. Get ready a pile of fresh horse manure which has been mixed with one-third as much bedding straw or litter. If very dry, sprinkle with water. When, in a day or two, it begins to steam, turn it well over, and in a day or so more, fill the dug-out space to within six inches of the top. Place the frame on this, and bank up the _outside_ with more manure. Cover the manure with earth. Fill the inside with earth six or eight inches deep, and water with a sprinkler. Put on the sash, and place a thermometer inside. It may go up to 120 degrees, but in a few days will come down to 90 degrees, when the bed is ready for planting. Seeds may be planted direct in the soil, but a more convenient plan is to fill shallow boxes, called “flats,” with soil, and plant the seeds in them, placing them in the hotbed. They are easily lifted if a slat is nailed across the middle, when the young plants are ready for transplanting into the—