VOL. LKVII.] PHILOSOPHICAL TRANSACTIONS. ^71 



the metal lightly on the polisher round and round, carrying the edges of the 

 speculum however, not quite half an inch over the edge of the tool, and now 

 and then with a cross stroke. 



The first putty, and indeed all the succeeding applications of it, should be 

 wrought with a considerable while ; for if time be not given for the putty to bed 

 itself in the pitch, and any quantity of it lie loose on the polisher, it will accu- 

 mulate into knobs, which will injure the figure of the metal : and therefore as 

 often as ever such knobs arise, they must be carefully scraped off with the 

 point of a penknife, and the loose stuff taken away with the brush. After the 

 putty is well wrought into the pitch, some more may be added in the same 

 manner, but never much at a time, and always remembering to work on it first 

 with the bruiser, for fear any gritty particles may find their way on the polisher. 

 If the bruiser be apt to stick, and do not slide smoothly on the pitch, the sur- 

 face of either tool may be occasionally brushed over with the soap and water, but 

 it must be remembered that the wet brush must be but lightly rubbed on the 

 soap. 



In the beginning of this process little effect is produced, and the metal does 

 not seem to polish fast, in some measure owing to its taking the polish in the 

 middle, and perhaps because neitiier that nor the bruiser move evenly on the 

 polisher : but a little perseverance will bring the whole into a good temper of 

 working ; and, when the pitch is well defended by the coating of the putty, the 

 process will advance apace, and the former acquiring possibly some little warmth, 

 the metal moves more agreeably over it, with a uniform and regular friction. 

 All this while the metal must have no more pressure than that which it derives 

 from its own weight and that of the handle; and the polisher n)ust never be 

 suffered to get dry, but as often as it has any tendency to do so, the edges of it 

 must be moistened with the hair pencil ; and now and then, even when fresh 

 putty is not laid on, the surface of the polisher should be touched with the 

 brush to keep it moist. 



When the polish of the metal nearly reaches the edge (for it always, as before 

 said, begins in the middle) you must alter the method of working ; for now the 

 round strokes must be gradually altered for the short and straight ones. Sup- 

 posing then you are just beginning to alter them ; after having put on fresh 

 putty, and gently rubbed it with 2 or 3 strokes of the bruiser, you place the 

 metal on the tool, and after a stroke or two round and round, give it a few for- 

 ward and backward, and from side to side, but with the edges very little over the 

 tool ; then having turned the metal -l round in your hand, and moved yourself 

 as much round the block (which must be remembered throughout the whole 

 process) you go on again with a stroke or two round, to lead you only to the 

 cross strokes, which are now to be principally used, and with more boldness. 



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