Vol. 32. OCTOBER 1866. No. 216. 



Published the First Day of every Month.-— Price 2s. 6d. 



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloch's 'Philosophical Magazine, 3 

 Nicholson's ( Journal,' and Thomson's ' Annals of Philosophy ' 



CONDUCTED BY 



SIR DAVID BREWSTER, K.H. LL.D. F.R.S. L.&E.&c, 

 SIR ROBERT KANE, M.D. F.R.S. M.R.I. A. 

 WILLIAM FRANCIS, Ph.D. F.L.S. F.R.A.S. F.C.S. 



FOURTH SERIES. 



N° 216.— OCTOBER 1866. 



WITH A PLATE, 

 Illustrative of Mr. R. Gill's Paper on an Air-pump without Clearance. 



LONDON: 



PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET, 



Printers and Publishers to the University of London. 

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