Vol. 34. AUGUST 1892. No. 207. 



Published the First Bay of every Month. — Price 2s. 6d. 



THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE, 



AND 



JOURNAL OF SCIENCE. 



Being a Continuation of Tilloclis 'Philosophical Magazine? 

 Nicholsons 'Journal? and Thomsons 'Annals of Philosophy: 



CONDUCTED BY 



LORD KELVIN, LL.D. P.R.S. &c. 



GEORGE FRANCIS FITZGERALD, M.A. Sc.D. F.R.S. 



AND 



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



N° 207.— AUGUST 1892. 



WITH TWO PLATES. 



Illustrative of Messrs. Edseb, and Stanseield's Paper on a Portable 

 Instrument for Measuring Magnetic Fields. 



LONDON: 



PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. 



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