2101. Though the making of putty be hardly within the gardener's province, yet it is fitting he should know that there are several sorts, of which the following are the principal: ï¿½ Soft putty, being a well-wrought paste of flour of whitening and raw linseed-oil; Hard putty, composed of whitening and boiled linseed-oil; Harder putty, in which a portion of turpentine, or what is called drying oil, is introduced; and the Hardest putty, composed of oil, red or white lead, and sand. The first is the most durable of all, because it forms an oleaginous coat on the surface, but it requires a longer time for drying. The hard sorts are apt to crack, if not soon well painted; and the hardest of all, though it appears to be impenetrable, and of the greatest durability, yet renders it difficult to replace a pane when broken. It seems, therefore, quite unfit for hothouses. Much depends on well working the putty some days before it is to be used; and, in general, that putty which has been ground and wrought in a putty-mill is to be preferred.