270 Mr Sang's Annual Report on the 



rest for the slowness of its proceeding. Experience soon removes 

 this objection. 



The first estimate of the relative amounts of skill required is 

 as far wide of the truth. A stranger to the art of turning has 

 only to take a tool in his hand and apply it against the work, to 

 be feelingly convinced that more skill than he had even imagined 

 is necessary. The roughness of the cut, if indeed he succeed in 

 making a cut at all, indicates that not the turning-lathe but the 

 workman has the skill ; but how different with the slide.rest ! 

 The tool once placed, we have only to turn the winch to make 

 work as good as that produced by the experienced artisan. It 

 is the slide-rest, not the man, that operates ; and this is clear, 

 for we may even employ the steam-engine to di'ive the leading 

 screw of the slide-rest. 



This conclusion, however, is hastily reached. The steam- 

 engine cannot determine on the acuteness of the edge, the pro- 

 per inclinations of its planes to the axis of the lathe, nor of the 

 projection which the cutter may have beyond its support. These 

 considerations require brains, and an active exercise of that m*a- 

 terial organ of thought. 



The hand-turner feels from the nature of the cut whether he 

 have placed his tool in the most advantageous position, and by 

 a motion which appears natural, adjusts the direction of the in- 

 strument. Great skill and considerable practice are needed for 

 the accomplishment of this motion; but we must not judge that 

 skill and practice are not needed by the slider.* His tool once 

 placed, remains there; while the finish of the work depends es- 

 sentially on the proper placing of the cutter; but the inconve- 

 niencies of an improper position are not experienced by himself; 

 he must divine their existence from the appearance of the mate- 

 rial, or from the sounds emitted by the machine ; and he can 

 only remove these by a change in the form or position of the 

 cutter. In the sharpening and placing of the cutter, then, is his 

 •whole skill shewn ; these accomplished, he leaves the advance- 



• Technically, we say to slide a cylinder, not to turn jt. 



