without affecting their Life or Limls. 257 



1 think it right to give this explanation in justice to Sir 

 Theophilus Biddulph, from whom my idea of the utility of 

 something of the kind arose, as also to show the difference 

 -between his invention and the trap I have made, which is 

 so very simple as hardly to require explanation. When set, 

 it only requires thai the two keys be withdrawn, and that 

 the trap be covered with a few loose leaves or mould. To 

 the trap I have attached a piece of chain and a screw to be 

 screwed into the ground, so as to prevent its being carried 

 away ; but against any person that may be caught such a 

 precaution is perhaps unnecessary, for any person who is 

 caught will find the jaws of the trap close so fast on the 

 leg that he caniiot drag the trap far without great pain, and 

 will consequently be glad to stand still and to call out for 

 relief. For the convenience of explanation I have applied 

 mufflers to the jaws of the trap, so that any person may put 

 ill his leg without the least inconvenience. I have even 

 tried it without, yet, though void of danger, the sensation 

 is not pleasant. The muffle will of course be omitted when 

 set for use, as it is not then necessary to guard against a 

 little inconvenience, otherwise the springs might be made 

 weaker. I remain, sir, 



Your most obedient humble servant, 



Woburn, Feb. 12, 1809. ROBERT SALMON. 



to C. Taylor, M.D. Sec. 



P. S. — Permit me strongly to recommend to the notice 

 Of the Society the earth screw attached to the trap, as excel- 

 lent for the purpose of fixing any thing steadily in the earth. 

 This screw is far superior to the common way of driving an 

 iron point or stake therein. 



I have employed it for several years in fixing cross- staffs 

 and other surveying instruments with great advantage. The 

 very act of driving a spiked instrument into the earth leaves 

 it loose with some play or movement, which prevents it 

 from being easily secured ; but with ? screw of this kind at 

 the bottom or the instrument it is firmly fixed in the ground, 

 and a turn of the screw will again fix it, if it should by any 

 means be moved or loosened. It may also be screwed into 

 the ground with any instrument upon it, which would be 

 spoiled by the act of driving it in. 



Description of Mr. Salmon's Man-Trap, it'hich detains the 

 Offender^ without injuring or maiming him. See Plate 

 VIrFig 1. 

 The principal figure in the fore-ground of Plate VI. is a 



Vol, 36. No. 150. Oct. 1810. R perspective 



