[3.  MARCH   1872.  No.  285 
Published  the  First  Day  of  every  Month.— Price  2s.  6d. 
THE 
LONDON,  EDINBURGH,  and  DUBLIN 
HILOSOPHICAL     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  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. 
FOURTH    SERIES. 
N°  285.— MARCH  1872. 
WITH  A  PLATE, 
llustrative  of  Mr.  G.  K.  Winter's  Papers  on  Testing  the  Metal-resistance 
of  Telegraph-wires  or  Cables  influenced  by  Earth- currents  ;  and  Obser- 
vations on  the  Corona  seen  during  the  Eclipse  of  December  11th  and 
12th,  1871. 
LONDON: 
PRINTED  BY  TAYLOR  AND  FRANCIS,  RED  LION  COURT,  FLEET  STREET, 
Printers  and  Publishers  to  the  University  of  London. 
Bold  by  Longmans,  Green,  Beader  and  Dyer  j  Kent  and  Co. ;    Simpkin,  Marshall  and 
Co. ;  Whittaker  and  Co. ;  andH.  BaiUiere,  London :— and  by  A.  and  C.  Black,  and 
Thomas   Clark,   Edinburgh;     Smith  and  Son,  Glasgow :— Hodges    and    Smith, 
Dublin :— Putnam,  New  York  :— and  Asher  and  Co.,  Berlin. 
