niities of which are placed hands capable of being moved lound 1 

 on: their extremities by pullies and ropes ; each of thefe . hands : 

 is capable of ten different . pofitions, which arc fufficiently dlf- 

 tinguifliable from each other, as may be feen in fig. 3, and 

 •which may reprefent the ten cyphers, and if we fappofe the hand 

 at £ to reprefent units, that at C to reprefent tens, that at D to 

 reprefent -hundreds,' and that at i^ thoufands,- It Is< plain that the 

 number of any word under ten thoufand may ber denoted,- by a 

 linglc arrangement of the parts of the inftrument, and that 

 thefe may be obfervT:d at a- great diftkmce by atelefcops.: for in^ 

 fiance, if i6 were required to reprefent the number 2701^ the- 

 hand at' 2^ isto be put into the fecond pofition, that at D into tha 

 feventh, C into the tenth, and E into the. firft pofition. If it 

 were neceffary to reprefent a word the number of which was 26^ 

 the hands at JT and at D are to be put into the tenth pofition, to 

 fignify no thoufands no hundreds^ that at Cintathe fecond, and 

 that at E into the fixth pofition. In order to work this inftru* 

 ment, there may be apulley affixed to the end of each haud,..and 

 a rope, the ends of which are to be joined together, is to pafs .. 

 over it, and alfo to pai& over another pulley of equal diameter at 

 the bottom, fo that the hand may be moved by moving the 

 pulley below; let the lower pulley be furnifhed with an index, 

 and let the numbers, which it may be required to reprefent by the 

 hand above, be written on a fixed circle round the lower pulley 

 fb that the index may be turned to any of them, and faftenedf 



tliere i. 



