BUILDING AND ORNAMENTAL STONES. 329 



soft limestone being at tlic rate of about 24 inches an hour, and in Car- 

 rara marble a little more than 9 inches an hour. Brittany granite is cut 

 at the rate of nearly 1| inches an hour, and even porphyry can be worked 

 at the rate of eight tenths of an inch an hour. In certain Belgian mar- 

 ble quarries the saw is said to have been used to advantage in cutting the 

 rock fiom the quarry bed. In thus utilizing it the floor is iirst cleared as 

 for channeling machines, and then, by means of large cylindrical drills, 

 fed with metallic sand, a shaft 27 inches in diameter is cut to the desired 

 depth, the cores being removed entire, as in the common tubular dia- 

 mond drills, Two of these Iiolcs are sunk at jiroper distances apart 

 and guides set up in them, on which move frames carrying pulleys of 

 a diameter somewhat less than that of the holes; over these pulleys the 

 cord-saw is stretched; motion is then imparted to the pulleys by a sim- 

 ple system of transmission, and the saws cut without interruption until 

 the bottom of the drill pit or shafl is reached.* A great saving of 

 time and material is clainsed for this invention, but although it seems 

 to proniise well none are at present iu use in this country, nor has the 

 author ever had ojiportunity for examining oue.t 



(7) Tlli: SAND BLAST. 



As already noted, the sand blast has been utilized to some extent in 

 the work of lettering head-stones, and for producing delicate tracings on 

 the Sioux Falls quartzite. That the process is still so little used is due, 

 as I am informed, to the opposition of trades-unions, and not to any 

 deliciency of adaptability in the process itself. 



(S) HAND IMPLEMENTS. 



Face hammer. — This is a heavy square-faced hammer, weighing from 

 15 to 25 pounds, and used for roughly shaping the blocks as they 

 come from the (piarry. It is sometimes made with both faces alike or 

 again with one face flat and the other drawn out into a cutting edge 

 (Fig. 10, PI. v). The cavil differs only in having one face drawn out 

 into a pyramidal point. 



Ax or pean hammer. — A hammer made with two opposite cutting- 

 edges, as seen in Fig. 13, PI. v. The edges are sometimes toothed 

 roughly, when it is called the toothed ax. 



I'afenI or hnsh hammer. — A hammer made of fOur, six, eight, ten, or 

 more thin blades of steel, bolted together so as to form a single piece, 

 the striking faces of which are deeply and sharply grooved. This ham- 

 mer is said to have been invented by Mr. Jose]»h Kichards, of (^>uiiicy, 

 Mass., about lS31-'40. As hrst constructed the head was comjiosed of 

 a single piece, instead of several, as now (see Fig. 12, PI. v). In some 

 works this is called the bush hammer. 



*A 111. Arch, juid Build. News, Nov. 7, Ir-'S'). 



t Tliis app.aratns is lij^nrcd and dcscrihcd in tlic SciciiMdc, Aiiicricaii Air Miucli 

 G, I88G, p. 147. 



