56 IMPRftVEp MAN-TflAI». 



Another slm- I think it right to give this explanation in justice to Sir 

 Tance for* the Theophilus Biddulph, from whom my idea of the utility of 

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



between his invention and the trap 1 have made, which is so 

 very simple as hardly to require explanation. When set it 

 only requires, that the two keys be withdrawn, and t]hat the 

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

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

 ed into the ground, so as to prevent its being carried away; 

 against any person tfiat 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 cannot 

 drag the trap far without great pain, and will consequently 

 be glad to stand still, and to call out for relief. l?or the con- 

 venience of explanation I have applied mufflers to the jaws 

 of the trap, so that any person may put in his leg without 

 the least inconvenience. I have even tried it without, yet, 

 though void of danger, the sensation is not pleasant. The 

 muffler will of course be omitted when set for use, as it is not 

 then necessary to guard against a little inconvenience, other- 

 wise the springs might be made weaker. 



I remain, Sir, 



Your most obedient humble servant, 



ROBERT SALMON. 



Ascrewcon-^ p. S. Permit me strongly to recommend to the notice of 



trived forfix- ^ s oc i ety the earth-screw attached to the trap, as excel- 

 mg any tning j ( . . • . . 



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

 grouud rp^ screw i s f ar superior to the common way of driving an 



iron point or stake therein, 

 very useful on I have employed it for several years in fixing cross-staves 

 various occa ^^ 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 a screw of this kind at the 

 bottom of 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 



HOPS. 



