The Goetz Anchors, and Caps for Wooden Posts. Figs. 7, 8, and 9 show a form of joist and girder anchor recently patented by the Goetz Box Anchor Company, of New Albany, Ind.

These anchors are made wedge-shaped so that it is impossible to pull them out of the wall, and the more weight there is upon the beam, the greater will be the bondage that holds beam to box and box to wall.

not even weakened by the space left in the wall, because the anchor remains, and the crushing strength of this cast-iron box is much greater than that of the wall. No break or breach is made in the wall, and the anchor that remains, securely held, forms a space for

the easy replacement of joist. The anchor provides a perfect and secure foundation for each joist. Fire from a defective flue cannot ignite a joist end, because it is protected by a ventilated cast-iron box.

The boxes, or anchors, also have air spaces in the sides, inch wide, which permit a circulation of air around the ends of the joist, effectually preventing dry rot in the ends of the timbers.

If timber is wet or unseasoned it will have a chance to dry out

S

Fig. 10.

Plate P, 1" to 2" thick; L, 1" x 1"; socket S, 4" to 5" deep.

after it is put in the building. These anchors are obviously greatly superior to the ordinary method of anchoring beams and girders to walls, and their use would, in case of fire, undoubtedly save much loss by the falling of the walls, which are almost invariably

pulled down by the ordinary iron anchors. The average weight of a box like Fig. 7, for 2 x 12 joist, is 15 to 17 lbs. ; of Fig. 8, from 12 to 15 lbs.

Fig. 10 shows the Goetz cap for wood posts. This cap holds all the timbers securely in place, provides ventilation about

the ends of the timbers, and permits the horizontal timbers to fall, in case of fire, without damage to the vertical posts.

These anchors and caps are recommended by the factory mutual insurance companies of New England, and can be made in any foundry, by paying a royalty of of a cent per pound on all that are made, to the Goetz Box Anchor Company, of New Albany, Ind.

P. Duvinage & Co. of Brooklyn. N. Y., have patented the anchors and cap shown in Fig. 11, and they have been used to a considerable extent. The cap differs from the Goetz cap principally in the substitution of pins for the projecting rib which holds the timbers. It is claimed that the pins do not cause the timbers to check and split, as is often the case with the rib, and it is also less work to fit the timbers to the cap. Either of these forms of caps and anchors is superior to those in common use. They must not be used, however, without a license from the patentees.

CHAPTER XXV.

MATERIALS AND METHODS OF FIRE-PROOF CONSTRUCTION FOR BUILDINGS.

The term fire-proof is applied to various kinds of buildings, sometimes correctly, but more often incorrectly.

The buildings most generally referred to by this term may be classed as follows:

1st. Those in which all the structural parts, both on the interior and exterior, are of non-combustible materials carefully protected from the action of fire by fire-resisting materials. (See also quotation from Chicago building ordinance, page 485.)

2d. Those built on the so-called "mill principle," and protected by fire-proof material.

3d. Those built in the usual manner with wooden construction, and protected by fire-proof material. Of these classes the first is the only one that is considered by experts to be absolutely impregnable to the effects of fire.

MATERIALS.

Various materials have been introduced for the purpose of making incombustible buildings, and for the purpose of fire-proof protection of other materials in structural parts of buildings, all more or less effective. Experience, however, has shown that the only materials upon which it is safe to rely are the products of clay, some concretes, and lime mortar under certain conditions. Plaster blocks have been found to be useless to withstand the effects of fire, moisture, and frost. The lime of Teil was for several years used in the manufacture of fire proof material, but to the best knowledge of the writer this has been discarded. All methods of fire-proofing by the use of exposed iron in any form are also acknowledged to be inefficient. Of all materials, burnt clay has the most numerous applications in incombustible building. It stands preeminently first as the most efficient fire-proof material in all departments of building, and especially so for interior filling of floors and partitions. For this it is used in hollow tiles of two general kinds. They are known by severa! different names: the one by such as porous terra-cotta, terra cotta lumber, cellular pottery, porous til

ing, etc.; the other by fire-clay tile, hollow pottery, hard tile, terracotta, dense tiling, etc For convenience, the first is herein referred to as porous tiling, and the second as dense tiling The terms "hollow tiling" and fire-proof tiling" will be used when both are referred to in a general way. They will be described in their

order.

Porous Tiling.-A substance formed by mixing sawdust with pure clay and submitting it to an intense heat, by the action of which the sawdust is destroyed, leaving the material light and porous, like pumice-stone. When properly made it will not crack or break from unequal heating, or from being suddenly cooled by water when in a heated condition. It can also be cut with a saw or edge tools, and nails or screws may be easily driven into it for securing interior finish, slates, tiles, etc. For the successful resistance of heat, and as a non-conductor, there is no building material equal to it. As a casing, covering, or lining for the protection of other material, it is to be preferred above every other material.

It should be manufactured from tough, plastic clays. A small percentage of fire-clay mixed in is desirable but not essential.

The proportion of sawdust should be from forty to sixty per cent., according to toughness of clay used. Care is required in manufacture that the work of mixing, drying, and burning be thoroughly done. The burning should be done in down-draught kilns by quick process. The product should be compact, tough, and hard, ringing when struck with metal. Poorly mixed, pressed, or burned tiles, or tiles from short or sandy clays, present a ragged, soft, and crumbly appearance, and are not desirable.

A fire-proof filling and protecting material should be substantial as well as incombustible. In a building made of absolutely incombustible materials it is of the first importance that the fire-proofing be able to withstand rough usage, for, in the event of fire, damage to the structural parts will be serious if the fire-proofing is dislodged, falls apart, or yields to the action of fire, or of water when a fire is in progress, or if it collapses under sudden loads, jars, or impact, although the material itself may not burn at all. In such buildings enduring qualities, both of the fire-proof material and its construction, are as vital and important as the incombustibility of the material. In the event of fire, the first danger is from the collapse of the material and not from its combustion. Experience has shown that fire-proof tiles of plastic clays, when porous, are more enduring than dense tiles, even if the dense tiles be of part or all fire-clay. Porous tiles are tough and elastic. Dense tiles are hard and brittle. The most essential requisites of a fire-proof filling and