260 



MANIPULATION. 



steel or brass, in which the diamond is set; this piece of 

 metal is connected to the handle by means of a swivel-joint 

 which works in the end of a brass ferrule attached 

 to the handle of the instrument. The handle is 

 generally composed of wood or ivory, the upper 

 part is round and slight, whilst the lower part is 

 much larger and flattened on two sides, for reasons 

 presently to be assigned. The amateur, when 

 taking a diamond in hand for the first time, must 

 not be disappointed if he fail to cut a strip from a 

 piece of glass : he may even persevere, and still 

 some time elapse before he is certain of making a 

 good cut — hence it has been thought that a few 

 words of instruction on this point would not here 

 be out of place. The diamond should be held in the 

 hand thus : — The upper part of the shaft or handle 

 should be placed between the fore and middle 

 finger, and one of the square sides of the lower 

 end pressed upon by the thtmib, and the opposite 

 square side by the middle finger. The side of the 

 oblong piece of metal in which the diamond is set 

 should now be brought against the edge of the 

 ruler, and by means of the swivel-joint it will 

 readily accommodate itself to it. Supposing we 

 wish to cut a strip from a piece of glass, we 

 must first lay the ruler on the glass, in the 

 position in which we wish the cut to be made; 

 the diamond held as already directed must be 

 placed against the edge of the ruler, at the spot 

 where we wish the cut to commence, and should 

 the operator have never cut with the same diamond 

 before, he should rest it on its point, and move it backwards 

 and forwards upon it, making the upper end of the handle 

 describe a curve, until the diamond marks or takes readily to 

 the glass. When the right position is»^t)btained, the diamond 

 may be drawn carefully along the ruler to the opposite end of 

 the glass, care being always taken that the pressure exerted on 

 it be not great, and that the same degree of inclination of its 



Fig. 168. 



