INSTRUMENT FOR COUNTING THE LIFTS FROM A MINE. 117 



bottom of the box, and then faften the latter {o, that it can Inftrument for 

 give way to any remaining inaccuracy of the other parts ofj^^f^j^fj^^ ^' 

 the gudgeon. mine. 



I have fent a drawing* x)f fuch a machine, which will be 

 eafily underftood, fmce the principle is the fame as in the 

 mode!. But as gins are commonly made ufe of in deep mines, 

 I have made it upon a larger fcale; viz. the firft wheel has 

 fixty-four cogs ; and this, with a pinion of four leaves, will 

 require fixteen revolutions of the gin, for one of the wheel. 

 Allowing ten yards for the circumference of the gin, it will 

 make one hundred and fixty yards of rope ; and confidering^ 

 that the faid wheel can nearly make two revolutions, and that 

 the catch will ftill a6l only once, it will confequently ferve 

 for a pit of three hundred yards deep, as well as for one of ten 

 or twenty. 



In this machine, the three wheels are placed one on another, 

 and the index is divided ; viz. the fifty on the fecond, and the 

 1000 on the third wheel. As the wheels move, the two hands 

 are flanditig, which will point out the numbers as exa6tly as 

 thofe in the model. Indeed, machines for hand windlalfes 

 may be made in the very fame way, and thereby be more 

 fimple, though the difTerence is but fmall ; viz. the box would 

 require but one hd and lock, and th,e two fmaller wheels be- 

 come unnecefTary. . 



Though in fetting the machine fo as to begirt counting wilh 

 one, it may eafily be effected by lifting out the fpring, and then 

 turning the wheel with the other hand, till both hands fland 

 upon one, yet, in the double index, the upper hand muft only 

 be fet thus with the wheel, and the lower may be moved rOund 

 on its focket. 



. In my humble opinion, my machines may be ufeful in two 

 ways; firft, to the honed- bank^sman, as they will fave him 

 t)ie trouble of noting down each box which is drawn up, and 

 prevent miftakes; fecondly, in the prevention of fraud, which 

 will be their greatelt and mofl important ufe. To. obtain this 

 end. It is necefllary that the machine be fo contrived, that 

 nothing etfentially wanted can be difengaged. I have there* 

 fore made the model fo as to fruftrateany fuch defign. All is 

 within Xhe box J and neither the endlefs fcrevv'can be difen- 



-♦ Thisddrawing is in the Society's ppfleflion. 



gaged 



