being locked into the corner plates without nails. The sides should then be covered, one at a time, the tin plates being put on with locked joints. All locked joints to be 1⁄2 inch, and nailed under the seams with 11⁄2-inch long barbed nails for 221⁄2-inch doors, and 14-inch barbed nails for 2-inch doors. No solder to be used. Use "terne" plate where doors are exposed to damp

ness.

Hardware for Sliding Doors.-The track to be of best quality flat rolled steel, 3%-inch thick by 31⁄2 inches wide and bolted every 22 feet with 3/4-inch bolts running through the wall, having nut and flanged washer on the opposite side. The hangers to be of wrought metal, x31⁄2 inches, and attached by 1⁄2-inch bolts. Wheel to have not less than 11⁄2-inch bearing on axle, roller bearing preferred, and to be of malleable or wrought iron; the long end of hanger to be not less than 18 inches, and to be drilled for not less than two 1⁄2-inch carriage bolts. For doors less than 6 feet wide two hangers are sufficient; for doors over 6 feet wide three hangers to be used. Wrought iron binders x31⁄2 inches, drilled for 3/4-inch bolts; each binder to have an angle flange at back end, I inch deep to notch in wall, or to have two bolts, to prevent sagging; two binders are required, one at side near floor and one at same side near top, into both of which the door closes. A roller guide to be located near bottom of door at opposite side from binder stops; guide to be of wrought metal, 2x2 inches, the base to be "U" shape, countersunk in floor and wall and bolted to wall; a flat piece of metal to be attached to front of door to take wear of roller guide. Chafing strips of 1-inch half-round iron to be screwed to door on side next wall, located one-third the distance from bottom to top of door, parallel to door track, ends to be 6 inches from side of door. Two handles required on each door; one large, heavy, wrought iron, bow-shaped handle to be bolted to front of door, and one handle to be countersunk flush with surface of door. Twc bumper shoes placed on the door where it strikes the binders in closing, to be of 1-16-inch plate iron. Hard plaited cord with a 160-degree fusible link, so placed in its length as to be in the open doorway when the door is open, to hold the door open by a weight on the end not attached to the door.

Hardware for Swinging Doors.-Wall eyes of wrought iron,

for 3/4-inch pin, built in wall or bolted through wall with 3/4-inch bolt, with 3-16-inch iron washer each side; bolts should always be put through brick work far enough from edge of opening to prevent weight of door loosening the masonry. The hinges should be of wrought iron, 3% x 21⁄2 inches, bolted to door with four 3-inch bolts; hinges to extend three-quarters way across door. The latch to be of wrought iron, 3% x 2 inches, bolted to door with 3-inch bolts; keeper to be wrought iron, and also bolted to door. Catch to be of heavy wrought iron built in the wall or bolted' through it.

All wrought iron sheaves, hinges and latches to be secured by bolts passing through door, the head of bolt resting against a washer next to the tin, the nuts being against the wrought iron. Do not use screws to attach any hardware except chafing strips, bumpers and automatic attachment. Do not use builders' ordinary cast iron hardware, and use only the best quality of bolts.

Sills should be of stone, built into wall at least 6 inches at each end, and extended under and flush with outer surface of door, or of wrought iron or steel plate not less than 1/4 inch in thickness, on brick, stone or concrete support, built into wall at least 6 inches at each end and extended under and flush with outer surface of door, or of concrete placed between suitable angle-irons and made flush with their upper surfaces. This angle-iron to be placed on each side of the wall, to be not less than inch in thickness, to have faces of equal width, to extend 6 inches beyond the opening at each end, to be held in place by 3/4-inch bolts run through the wall and to have its horizontal face extend under and its edge flush with the outer surface of the door.

The Intel should preferably be a brick arch.

Sliding doors must overlap sides and top of opening 4 inches. Swinging doors to shut into a brick rabbet in wall or into a 21⁄2 x 21⁄2 x 4-inch iron rabbet secured on each side with 3/4-inch bolts through the wall, or into an approved door frame having jambs of rabbetted 21⁄2-inch angle-iron 14 inch thick, and held firmly in place by at least three 3/4-inch bolts each side, passing through wall, with metal sill well secured to the iron frame and catches for latches, also pin blocks to receive the hinges, of heavy wrought iron and properly riveted to the iron frames.

Vertical sliding doors can be used where swinging or horizontally sliding doors cannot be used. Malleable or wrought iron wheels should be used, and the cord connecting with the fusible link should be attached to lower part of door, passing over its proper pulley to the left and supporting the smaller weight. The heavier weight is permanently connected by a wire cable to the upper loop at top of door, and is adjusted to prevent the sudden dropping of the door, but allowing it to close when link fuses.

STANDARD TIN-CLAD FIRE SHUTTERS (National Board of Fire Underwriters).—The construction is the same as that of standard tin-clad fire doors, excepting that only two thicknesses of %-inch boards are required. When the shutters are made in pairs the edges coming together should be flush and not rabbeted. Hinges to be of wrought iron 5-16 x 14 inch, secured by bolts passing through the shutter, with washers under the bolt heads. The pin, or eye blocks, to be of substantial wrought iron, set in the wall or bolted through the wall. The shutters must be hung next to masonry, either overlapping window openings 4 inches or fitting close to the inside openings, and must be securely shut by an iron bar 3% x 11⁄2 inches bolted through the shutter, and at least one shutter in three on each floor above the first to be constructed so that it can be operated from both the inside and the outside; catches must be bolted to the shutter.

STANDARD IRON DOORS, VAULT PATTERN (National Board of Fire Underwriters).-The sills must be of iron or steel and raised not less than 2 inches above the floor on each side of the wall; if they are of plate iron or steel the edges must be securely fastened to 11⁄2 x 11⁄2 x 4-inch angle-iron, or heavier, on the inner side of the wall frame; in all cases they must rest substantially on the solid brick wall and extend to the upper edge of the wall frame. The basement floor must be of stone or concrete where the doors are to swing; in no case to be of wood unless the door swings clear of wood at least 6 inches. The wall frame must be of 4 x 3 x 3⁄41⁄2-inch angle-iron, or of 4 x 3-inch bar iron stiffened by 11⁄2 x 11⁄2 x 11⁄4-inch angle-iron riveted on the back; the bottom pieces of frame to project 2 inches above floor, and each set of wall frames to be connected

by bars of 14 x 4-inch iron, spaced not over 24 inches apart all around, except where sill acts in place of bars, or by 5%-inch bolts through the wall and spaced not over 24 inches apart, and the top and bottom pieces of wall frame to be joined to side pieces by wide splice plates of 38-inch iron securely riveted in place. Door plates must be securely riveted to the panel frames and panel bars, and must be of 3-16-inch iron or steel thoroughly straightened, and must overlap wall frame at least 1 inch on all sides, or if doors are flush, to shut into at least 5-inch rabbet all around, formed by angle on back of wall frame. Panel frame must be made of 2 x 2 x 38-inch angle-iron, continuous with bent corners or with corners reinforced by fillet angles where joined, the fillet angles being securely riveted in place; the frame to be stiffened with 2 x 2 x 3%-inch angle-iron panel bars, with ends offset so as to extend over sides of frames, or ends may be fastened with fillet angles, each frame to be provided with at least two panel bars, and where doors exceed 7 feet in height panel bars not to exceed 2 feet part.

Fittings. At least three wrought iron hinges must be used, those riveted to the wall frame to be at least 4 x 3 inches and made of 3%-inch iron or heavier, and to be fastened by three 3-inch rivets; the hinges on the doors must be constructed of 2 x 38-inch bar iron bent to overlap the panel frame on the hinge side; upper and lower hinges to extend across the door to panel frame on opposite side; center hinge to extend at least one-half of the distance across the door; must be securely riveted to door plate and through panel frame on each side, pins being of 5%-inch turned steel.

Doors to be secured by at least three lever bars of 11⁄2 x 38-inch iron, working together, upper and lower lever bars not to exceed 12 inches from upper and lower edges of door opening, and must be secured both in front and back by at least two lugs or binders on each side, made of 8-inch round iron passing through holes in the angle-iron panel frame when the door is closed; lugs to be so arranged that they will bind door to the wall frame when it is closed and latched, and to be securely riveted or bolted to the wall frame and in back of wall frame.

Rivets to be of Norway iron, at least 3% of an inch in diameter and spaced not over 6 inches apart.

Steel rivets should not be used. DOUBLE SWINGING DOORS IN PAIRS.-To have two opposite doors fastened together by hooks of 5-inch round iron, bolts or spring catches at top and bottom, and the righthand door to fold over left-hand door, lapping at least 1 inch, or, where the doors are flush, to fold into rabbet at least 5% inch; catches to be of 2-inch Norway iron securely riveted through door plate and angle-iron panel frames.

SLIDING DOORS, NOT AUTOMATIC, to slide in channels at the top and bottom, the latter channels to be formed by two angle bars 21⁄2 x 3% and 11⁄2 x 4 inches, the top channel to be formed by two angle bars 2 x % and 11⁄2 x inches; they must be securely riveted or bolted to the wall frame, and where they extend beyond the wall frame, to be firmly bolted to the wall by expansion bolts (1⁄2 x 41⁄2 inches); the lower channel to extend beyond the wall frame at least 12 inches on the side toward which the door opens. The doors must be secured both in front and back by at least two lugs or binders on each side, made of %-inch round iron passing through holes in the angleiron panel frame when the door is closed, the lugs to be so arranged that they will bind door to the wall frame when it is closed and latched, and must be securely riveted or bolted to the wall frame and in such manner as to prevent turning. The hangers to be of the anti-friction pattern and securely fastened to the door plate by at least four 1⁄2-inch machine bolts at each fastening, at least two hangers to be placed on each door; the wheels must be of cast iron 34 x 41⁄2 inches, and may be constructed with curved grooves so as to bear only on each edge of the 1⁄2-inch track, which latter must be without incline, of 1⁄2 x 1⁄2-inch iron securely riveted on the upper side of the angleiron channel, and to be perfectly true and without obstruction to wheels.

The door must be provided with a latch formed of 2 x 3%-inch iron, to which the handle is fastened.

AUTOMATIC SLIDING DOORS.-The cord on the latch side to be of flexible phosphor bronze, securely attached to the door; the remainder of the cord may be of the usual form; the link must be so placed as always to be in door opening, and so arranged that when it gives way under heat a sufficient excess