All of the stones which are suitable for the heavy walls which we have described should he large, and will require the use of derricks in handling. If the building is to be one of great size or height, a system of three or four large derricks will probably have been started, swinging from some central scaffold, and guyed to this and to each other. For a building of hut three or four stories however, the builder would probably use a series of smaller derricks supported each by its own guy ropes. The superintendent should make sure that the ropes are strong and not frayed out, that the mast and boom are neither cracked nor sprung, and that the running gear is strong and shipshape. The securing of the guy ropes is a very important matter, and should be noted by the superintendent. Although it belongs to the contractor to do this, a careful inspection by the architect will doubly insure the safety of all concerned. In suburban or out-of-town work the guys will usually be secured to a convenient tree, and this should be a young or evidently sound tree, or if posts have to be put down, as will be necessary in the city, they should be set deep in the ground with the earth well tamped in again. The guys must be at all times drawn taut, as a loose guy will be given a sudden and dangerous strain if a heavy stone is swung around so as to bring its weight upon it.

The derrick will allow of heavy stones being carefully set, and his will be especially noted in the handling of the capstones for the piles. These will have been selected for an even bed and can be shifted until they rest immovable on the piles. In bedding, the heavy stones may be held suspended over the place where they are to lie while an even bed is being prepared, and, if neces-sarv, the stone may be lowered and then raised again before the final setting, so that the impression will show where the bed will need fitting.