Vol.4. JULY 1877. No. 22. 



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



ft' 



THE 

 LONDON, EDINBUEGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE. 



AND 



JOURNAL OF SCIENCE. 



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

 Nicholson'' s ^Journal,'' and Thomson s 'Annals of Philosophy.'' 



CONDUCTED BY 



SIR EGBERT KANE; LL.D. F.R.S. M.RJ.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. 



FIFTH SERIES* ^ 



<e^. 



W 22.-- JULY 1877. 



LONDON: 



S, BED LION COURT, FLEET STREET, 



the University of London. 



LIBRARY OF CONHRF^^ ?S er; Kent and Co.; Simpkin, MarshaU and 

 v^l OUI^UHLOO, iJ^ A. and 0. Black, and Thomas Clark, Edin- 

 dges, Foster, and Co., Dublin: — Putnam, 



UNITED STATES OF AIV3ERICA. *^ 



