Vol.21. MAY 1886. No. 132, 



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 Tilloclis 'Philosophical Magazine,"* 

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



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. <fec. 



AND 



WILLIAM FRANCIS, Ph.D. F.lM ftBJLS. F.O.S. 



FIFTH SERIES 



N° 132.-MAY 1886 

 WITH TWO PLATES. 



Illustrative of Prof. Langley's Paper on Id visible Heat-Spectra and the 

 Eecognition of hitherto Unmeasured Wave-lengths ; and Mr. Baily's 

 on a Map of the World on Plamsteed's Projection. 



LONDON: 



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