344 Dr Traill on the Introduction into Scotland of 



are, as usual in such works, of soft iron -plates, secured in a 

 frame ; and operate on the stone by means of quartz-sand and 

 water, applied as in slicing marble. No emery is requisite in 

 these operations, the particles of siliceous sand being sufficient 

 to cut the quartz, the hardest material in the granite. Fre- 

 quently 14 saws are used in a single frame ; and occasionally 

 they have had as many as 18 employed at once on a single 

 block of stone. The progress of the work, of course, is slow ; 

 it requiring a whole day to cut a groove two- thirds of an inch 

 in depth in th6 granite. The slabs, when cut, are polished by 

 moving one over the other, by appropriate machinery ; siliceous 

 sand being first interposed, and then emery of various degrees 

 of fineness, until the requisite degree of lustre is obtained. 



The first dressing of the granite blocks into parallelepipeds, 

 cylindrical masses or other curved forms, is performed by 

 hand-picks, with short handles, and lieads about 4 pounds in 

 weight; which the woi'kmen, fi'om long habit, wield with sur- 

 prising accuracy. The sui-faces are then reduced to a regular 

 form by means of well tempered chisels, urged l>y iron mallets ; 

 the chisels require a very particular tempei-, which must be 

 neither very hard nor vei'y soft, else they would either lose 

 their edge by chipping, or fail to cut the stone. I observed 

 that they frequently require sharpening in the more delicate 

 kinds of work. The chisel is held by the workman very ob- 

 liquely to the surface of the stone, and he sepai*ates very small 

 particles at a time. 



I have already described the polishing of plane surfaces. 

 Circular forms, such as stelce, frusta of columns, as pedestals 

 I'or busts, vases, and the like, are fixed in well-contrived 

 lathes, and are whirled round by machinery, while the sand 

 and emery are applied to their surfaces by means of thick 

 plates or bars of iron, previously forged to their various cur- 

 vatiu-es, when they are not cylindrical. 



I saw a large vaso, about 4 feet in diameter, prepared by 

 the chisel for the process of polishing. Its graceful curves 

 were beautifully and accurately cut by the chisel ; the iron 

 bars, 1 or 1;^ inch in thickness, neatly forged to its various 

 curves, lay beside it ready to be applied, when it was fixed in 

 the lathe. 



In the warerooms were many finished articles of great 



