328 



REPORT ON NATIONAL MUSEUM, 1880. 



tent, but have been found too expensive for ordinary work. In sawing 

 slate circular saws are used, such as are employed in sawing lumber. 

 Philo Torolinson, who was engaged in marble sawing at Marbledale, 

 Oonu., near the date 1800, is stated by Professor Seeley* to have been 

 one of the first to successfully apply the gang-saw system in this 

 country. 



For sawing circular apertures in the tops of wash-stands or getting 

 out tops for small tables a saw made of plates of soft iron bent into 

 the form of a cylinder and revolved by a vertical shaft is used. Sand 

 emery, or globules of chilled iron form the cutting material, as in the 

 saws just mentioned. 



McDonald Storuo Cutting Machine. 



A recent European invention for sawing stone consists of a twisted 

 cord of steel, made to run around pulleys, like a band-saw. The cord is 

 composed of three steel wires loosely twisted together, but stretched 

 tightly over the pulleys, and is made to run at a high rate of speed. 

 The swift successive blows from the ridges of the cord, delivered along 

 the narrow line, disintegrates the stone much more rapidly, it is claimed, 

 than tlio iron blades fed with sand, the usual rate of cutting in blocks of 



*Op. ciL, p. 29. ■ 



