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XXXVII. — Description of an Instrument for 

 ascertaining the Specific Gravity of Bodies, 

 without the Use of Weights or Calculation. 



By Alexander Apte, F. R. S. E. & M. W. S. 



(Read l6tk December 1820. ) 



This instrument is a simple lever of a square form, 

 balanced on a centre. One arm of the lever is 

 made considerably longer than the other, to allow a 

 greater range of division. On the long arm, a sli- 

 der and hook, A, (as represented in Plate XXIII. 

 Figure !.,) moves freely ; the upper part of the 

 slider is opened, to show the divisions on the 

 upper surface of the lever ; and there is an index- 

 line in the centre of the opening. The divisions 

 are numbered from 1.1 up to 212 ; and each prime 

 division as far as 4, which is the useful part of 

 the scale, is subdivided into 10, and numbered 

 1.1, 1.2, &c. The fixed cylindrical weight at the 

 extremity of the short arm is merely to counter- 



