The sunken pit described on page 98 may be readily converted into a hot-bed; all that is necessary to do being to place hot manure or other heating material in the pit and tread it moderately firm with the feet. The manure should fill the pit to the depth of two feet, and then be covered with five or six inches of light rich soil, on which to sow the seed. This sunken pit prevents the escape of heat from the manure much better than when the hot-bed is made on the surface in the usual way. The preparation of the heating material for the hot-bed requires some attention. It should be manure fresh from the horse-stable, and when they can be procured, it is better to mix it with about an equal bulk of leaves from the woods. If the weather is very cold, the bulk of manure must be of good size, from five to six wagon loads, thrown in a compact conical heap, else the mass may be so chilled that fermentation cannot take place and no heat generated. If a shed is convenient, the manure may be placed there, especially if the quantity is small, to be protected from cold until the heat begins to rise. The heap should be turned and well broken up before being used for the hot-beds, so that the rank steam may escape and the manure become of the proper "sweetened" condition for the healthy germination of the seeds. After the manure has been packed in the pit to the depth and in the manner described, the sashes should be placed on the frame and kept close until the heat is again generated in the hot-bed. Now plunge a thermometer into the manure, and if all is right it will indicate 100 degrees or more, but this is yet too hot as bottom heat for the growth of seeds or plants, and a few days of delay must be allowed until the thermometer indicates a falling of 10 or 15 degrees, then the soil may be placed upon the manure and the seeds sown, or plants set out in the hotbed. Amateurs are apt to be impatient in the matter of hot-beds, and often lose their first crop by sowing or planting before the first violent heat has subsided. Another very common mistake is, in beginning too early in the season. In this latitude nothing is gained by beginning before the first week in March, and the result will be very nearly as good if not begun until a month later. There are two or three important matters to bear in mind in the use of hot-beds. It is indispensable for safety to cover the glass at night with shutters or mats until all danger of frost is over, for it must be remembered that the contents of a hot-bed are always tender from being forced so rapidly by the heat below, and that the slightest frost will kill them. Again, there is danger of overheating in day-time by a neglect to ventilate when the sun is shining. As a general rule it will be safe in all the average days of March, April, and May, to have the sash in the hot-bed tilted up from an inch to three inches at the back from 9 a.m. to 4 p.m. Much will, of course, depend upon the activity of the heating material in the hot-bed, the warmth of the weather, and the character of the plants in the bed; so that we can only give a loose general rule. Numbers of our amateur friends come to us every season lamenting that themselves or their men in charge had omitted to ventilate their hot-bed, and on their return home from business at night, found all the contents had been "boiled" up. Or the complaint may be on the other extreme, that the plants are frozen through neglect to cover them at night. A hot-bed requires a certain amount of attention, which must be given at the right time, or failure is certain.