Vol. 28. JULY 1889. No. 170. 



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



^>-> THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 

 JOURNAL OF SCIENCE. 



Being/ a Continuation of TilloeK s '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. &c. 



AND 



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



FIFTH SERIES. 



N° 170.— JULY 1889. 



WITH ONE PLATE. 

 Illustrative of Mr. C. V. Boxs's Paper on Quartz as an Insulator. 



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