Marx & Co.; Pavin de Lafarge; Plkettyj Rabltz; Rari- 

 some; Roebling; Sanders; Siegwart; Stolte; Thacher; 

 Walser-Gerard; Wayss & Freytag; Williams; Wunsch. 



The Johnson bars are among the best known. The 

 Kahn are in great vogue. The Thacher and Diamond, 

 made by the Concrete Steel Engineering Co., are much 

 used. The Clinton Wire Cloth Co.'s system is one of the 

 best known, while the Unit and Hennebique are being 

 patronized extensively. The International Fence & Fire- 

 proofing Co. makes a good form of reinforcing. Some of 

 the recently introduced forms in America are : The Ga- 

 briel, C. A. T. Turner, Maxwell (American Concrete Steel 

 Co.), the system of the General Fireproofing Co., and 

 Ferro-Inclave, put out by the Brown Hoisting Machinery 

 Co. mostly for roofing. The Trussed Concrete Steel Co., 

 owners of the Kahn patents, have recently brought out 

 the Cup-Bar and a style of expanded metal reinforcement. 



FORMS. 



Formwork depends on the type of construction, thick- 

 ness of slab and consequent large dead load of slab and 

 required alignment of the completed structure. For floors 

 a live load of 35 Ib. per sq. ft. would appear sufficient. 

 They should be of sufficient rigidity that the vibrations 

 are not severe enough to affect the setting: of the 

 cement. All forms should be put together so that they 

 can be easily removed and should be made to take any 

 swelling which may occur. This can be done by beveling 

 one edge. Open jointed canvas lined molds are sometimes 

 used. Dressed lumber should be used where finished sur- 

 face Is desired. To prevent concrete from sticking to the 

 molds, oil, paper and tin or sheet iron are used. Win-re 

 corners are likely to be broken off, bevel strips are used. 

 Openings should be left in the bottom of columns to re- 

 move sawdust, etc. Bands are placed closer at the bot- 

 tom than at the top of columns; battens used about 18 in. 

 o. c. on beams and girders, every other one projecting 4 

 In. below bottoms to nail on cross piece; joists placed at 

 each batten to brace sides of beams and girders; strips 

 nailed along battens to support joists; bottoms of beams 

 and girders shored. Forms can be held together by rods, 

 wires or special devices. The span of flooring, siding, 

 joists and shoring can be computed from the following 

 data and tables: 



