1 26 Prof. Hare's improved Eudiometrical Apparatus* 



Example: — Given x 2 — llx + 35 = 0. To find the values 

 of x. 



Here x = ?'gp . Moreover, — — 



d 17- 



X 2 



= 35. 



Hence, 17*— d* =140 or, d 2 = 149. 



.\ J = + V 149 = + 12 . 206 + &c. 



.-. x = (17 + 12 . 206 -f &c.)-r-2. Or, (17-12 . 206 + &c.)h-2 . 

 = 14.603 + &C, or 2.397 + &C. 

 I will not trouble you with any more examples, as there is 

 no need. I remain, Dear Sir, 



Your most obedient and much obliged servant, 

 Chelsea, June 20, 1828. Joseph Seers. 



XXIII. Improved Eudiometrical Apparatus. By R. Hare, 

 M.D. Professor of Chemistry in the University of Pennsyl- 

 vania *. 



I. Piston Valve Volumeter. 

 f" HAVE contrived some instruments for taking volumes of 

 **- gas at one time, precisely equal to those taken at another 

 time. I call them volumeters, to avoid circumlocution. They 

 are of two kinds, one calculated to be introduced into a bell 

 glass, over water, or mercury; the other may be filled through 

 an orifice, as is usual in 

 the case of filling a com- 

 mon bottle over the pneu- 

 matic cistern. The an- 

 nexed figure will convey 

 a due conception of one 

 of them, which having a 

 piston, I call the piston 

 valve volumeter. 



The lever L is attach- 

 ed by a hinge to a piston 

 p, which works inside of 

 a chamber C. The rod 

 of this piston extends be- 

 yond the packing through 

 the axis of the bulb B to 

 the orifice O in its apex, 

 where it sustains a valve, 

 by which this orifice is 

 kept close, so long as the 



* From the American Journal of Science, with corrections and additions 

 by the Author. 



pressure 



