(C.) Nothing is more easily forced than lettuce. Indeed, we doubt whether anything is better fitted for the purpose than the common hotbed frame. For artificial heat, stable manure or leaves are preferable. Very little heat is required; over 55º may be considered injurious, unless the plants are very near the glass, which, in any case, they ought to be. If it were desirable to grow them very extensively, no better plan could be adopted than to have long pits constructed with boards or brick, and the whole heated by hot-water pipes carried around on the inside. This could all be done in connection with the small propagating house inquired about - -one boiler heating both. For a propagating house, and, indeed, for any kind of greenhouse structure where heat and light • in winter is an object, a lean-to house, with a south or southeast aspect, is preferable to any other. In a house expressly for propagating, it is best to have a pit built, so as to contain a few feet deep of tan or leaves, or even sand, with the view of having a slight bottom heat or material to keep moisture around the pots. Sashes are not essential, if you provide sufficient ventilators in the front and back walls to keep down the temperature when it is likely to rise too high.

A house can be built at a considerably less cost, and will cost less to maintain artificial heat, when the roof is built on the house without movable sashes. The entrance should be at one end - at the warmest.

Where coal and lumber are cheap, houses and frames may be constructed of wood more profitably than of any other substance.