280 Mr Wilson's Description of an Improvement on 



period of decrepitude. It is also shewn that the mode in which 

 this energy shews itself depends upon local causes. The se- 

 cretion of milk, the return of the menses, and the growth of 

 the teeth, may in most cases be attributed to an irritation ap- 

 plied to the parts poncerned. In some instances, these changes 

 are accompanied by symptoms of constitutional irritation, and 

 fatal results have followed in more than one case ; a fact which 

 connects the physiology of the subject with practical medicine. 

 Dr Mehliss's book is, on the whole, interesting ; and con- 

 tains many curious details, and some important physiological 

 views. 



Description of an Improvement in the Common Vice, and Vice- 

 Chuck^ zvhereb// the action of the Screzv is made perfect. * By 

 Mr lloBKRT WiLsox, Engineer, Paul's Work, Edinburgh. 

 Communicated by the Society for the Encouragement of 

 the Useful Arts in Scotland, f 



In the common vice-chuck and hand-vice, the screw is fixed 

 to one of the arms, and the nut which works on it revolves ; 

 and as the arms are jointed, it follows that to render the appli- 



• Read before the Society for the Encouragement of the Useful Arts in 

 Scotland, loth Feb. liiS"] ; and obtained the Society's Silver Medal, value 

 Five Sovereigns, 6th December 1837. 



•f- JReporf of the Committee of the Society of Arts for Scotland on Mr Wilsons Im- 

 provement on the Common Vice and Vice-Chuck. 



The great and acknowledged defect of all vices which turn on centres is, 

 that the screw cannot act fairly at all distances. This defect is found also in 

 spring-compasses and callipers. 



The very simple and efficient plan adopted by Mr Wilson is to give to the 

 moveable arm such a form as may cause the nut to bear upon its diameter, to 

 whatever distance the cheeks of the vice may be opened ; in this way pre- 

 venting entirely every undue strain upon the screw. 



•Your Committee have great pleasure in reporting, that the curve given by 

 Mr Wilson completely produces the required eifect ; and that there is this 

 farther advantage in the method, that it can be applied even to vices that 

 are already constructed, — a piece of steel of the requisite form has only to be 

 placed between the washer of the nut and its present bearing. , 



