Vol.7. FEBRUARY 1879. No. 41 



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



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE. 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine? 

 Nicholson's 'Journal ,' and Thomsons 'Annals of Philosophy .' 



CONDUCTED BY 



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

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



A2tt> 



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







- 



FIFTH SERIES. 



N° 41.— FEBRUARY 1879. jfc 



WITH THREE PLATES. / 



Illustrative of Professors Perry and Ayrton's Paper on the Music of 

 Colour and Visible Motion, Prof. N. S. Maskelyne's on the 

 Crystallography of Nitrosoterpenes, and M. v. Lang's on a Ho- 

 rizontal Goniometer. 



LONDON: 



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Sold by Longmans, Green, Beader and Dyer ; Kent and Co. ; Simpkin, Marshall and 

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 New York : — and Asher and Co., Berlin. 



