When buildings stand very near each other, timber-work cannot be put together outside of the walls, and it therefore becomes necessary to adopt the arrangement shown in Fig. 9, all the work being done here beneath the structure. The cross-pieces, _a_, occupy here the entire width of the house, and are spaced about 36 inches apart from axis to axis. The structure rests upon two pieces of timber work constructed like the ones mentioned above. Besides this, it is necessary to utilize the timbers, L, of the flooring, P, for supporting a part of the load. During the widening of State Street, in Chicago, several three or four story brick structures were moved in this way. One of these houses was set back about four feet without the necessity of lifting it. Apertures (Fig. 10) four feet in length were cut in the foundation walls, the edges were made level, and planks, _c_ and _c'_, were inserted and fixed in tightly by wedges. The intervening masonry was removed, and, after laying planks alongside of those already in place, the structure was put in motion in the ordinary way. When single threaded screws are employed for moving buildings, it requires much time and manual labor to place and move the pieces. For the purpose of securing greater rapidity in these operations, Mr. Hollingsworth has devised a sort of jack-screw (Fig. 11) that consists of a steel screw about eight feet in length and three inches in diameter, provided with two threads, running in opposite directions. The nuts are set into the corresponding extremities of two beams, one of which abuts against a cast iron brace-block, _n_, held in place by a stirrup-iron, _t_, while the other bears against the string-pieces, _b_. Thanks to this arrangement, a structure may be moved at one time over a length of 6 feet instead of 1.3, the latter being the maximum travel with single screws. The method in which slide beams, f, are prolonged in view of resisting the pressure of the jacks is scarcely employed at present, the objection to it being that it occasions changes of direction from the line formed by the timber work. For this reason, contractors prefer to use independent posts to receive the jacks.--_Revue Industrielle_. [Illustration: FILTER FOR INDUSTRIAL WORKS] * * * * * FILTER FOR INDUSTRIAL WORKS.