THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



CONDUCTED BY 



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

 SIR WILLIAM THOMSON, Knt. LL.D. F.R.S. &c. 



AND 



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



"Nee aranearnm sane textns ideo melior quia ex sejila gignnnt, nee noster 

 quia 



vilior quia ex alienis libamus ut apes." Just. Lips. Poht. lib. i. cap. 1. 



VOL. XXIL— FIFTH SERIES. 

 JULY— DECEMBER 1886. 



/ SJ~AA1_ 







ulXj &X 



LONDON: 



TAYLOE AND FRANCIS, RED LION COURT, FLEET STREET. 



SOLD BY LONGMANS, GREEN, AND CO. ', KENT AND CO. ; SIMPKIN, MARSHALL, AND CO. 



AND WHITTAKER AND CO.; AND BY ADAM AND CHARLES BLACK, AND 



T. AND T. CLARK, EDINBURGH; SMITH AND SON, GLASGOW J 



HODGES, FOSTER, AND CO., DUBLIN; PUTNAM, NEW YORK; 



VEUVE J. BOYVEAU, PARIS ; — AND ASHER AND CO., BERLIN. 



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