INSTRUMENT FOR EXTRACTING HARD SUBSTANCES, 175 



cafe of exigence in the fpring and fummer : If this happen to 

 be (b, then it is at the expence of fprings ; for we find the ge- 

 nerality of fprings become languid, or entirely ceafe to flow 

 at the end of a long drought. As to the few fprings that feera 

 to be little affected by dry or wet feafons, they form exceptions 

 which it would not be difficult to account for. 



VII. 



Defcription of an Infirument for extracting Hard Subftances which. 

 £ may flick during their Pajfage to the Stomach. By G. C. 



To Mr. NICHOLSON. 

 SIR, 



ENCLOSED^ I fend you a drawing of an untried inflru-I^^ent for 

 ment ; if you think it likely to accomplish the end for which f tom the t h roaU 

 it was defigned, you will, perhaps, give it a place in your 

 very ufeful work. This inftrument, I conceive to be an im- 

 provement of that commonly ufed for forcing down any hard 

 fubftances that may flick between the mouth and the ftomach. 

 In many cafes nails, pins, and other metallic matters, get into 

 this fituation, when it would undoubtedly be preferable to 

 draw them up through the mouth, inftead of palling them into 

 the ftomach> where they are no fooner arrived, than they 

 furnifh a new fpecies of danger to the fufferer.. With this Description* 

 view the following inftrumeni was conftrucled. A, B, PI. XI. 

 is a rod of whalebone, having a fmall groove down the middle, 

 from end to end, large enough to contain a ftrong filken 

 thread ; this thread is confined to the groove by a few lap- 

 pings of fine waxed filk. At B, is faftened, as ufual, a fponge, 

 about one third of the common fize. Juft above the fponge 

 is fixed a fmall pulley, round which the filken thread winds, 

 and returning up the oppofite fide of the whalebone to that on 

 which it defcended, is tied fan 1 to the bottom of a fmall leather 

 cap C. Above this cap, at D, are faftened 12 or 14. fmall 

 filver wires, made to fpring into the form reprefented in Fig. 2. 

 Thefe wires by means of loops at their ends, fupport a round 

 bag of net-work of fine filk, perforated in the centre to admit 

 the whalebone rod. Thefe wires, together with the bag, 

 rnuft be capable of being inferted and confined in thq cap C, 



