VI  CONTENTS  OF  VOL.  XLIII. — FOURTH  SERIES. 
Page 
Notices  respecting  New  Books  : — 
Monthly  Notices  of  the  Royal  Astronomical  Society     305 
Observations  of  Comets  from  b.c  611  to  a.d.  1640.  Ex- 
tracted from  the  Chinese  Annals  by  John  Williams 305 
Weather  Charts  issued  daily  by  the  Meteorological  Office.  306 
Mr.  B.Williamson's  Elementary  Treatise  on  the  Differen- 
tial Calculus,  containing  the  Theory  of  Plane  Curves  .  .    307 
Mr.  W.  Ogilby's  New  Theory  of  the  Figure  of  the  Earth, 
considered  as  a  Solid  of  Revolution 308 
Proceedings  of  the  Royal  Society : — 
The  Astronomer  Royal  on  a  supposed  Alteration  in  the 
amount  of  Astronomical  Aberration  of  Light,  produced 
by  the  passage  of  Light  through  a  considerable  thickness 
of  Refracting  Medium   310 
Proceedings  of  the  Geological  Society  : — 
Prof.  A.  E.  Nordenskjold  on  the  Greenland  Meteorites  . .    314 
Mr.  H.  Woodward  on  the  Relationship  of  the  Limulidce 
(Xiphosura)  to  the  Eurypterida  and  to  the  Trilobita    . .    314 
Prof.  O.  Heer  on  Cyclostigma,  Lepidodendron3  and  Knorria 
from  Kiltorkan 315 
Mr.  G.  Maw  on  the  Geology  of  the  Plain  of  Marocco,  and 
the  Great  Atlas 315 
An  Experiment  in  reference  to  the  question  as  to  Vapour- vesicles, 
by  T.  Plateau     . 316 
On  the  Absorption-spectra  of  Chlorine  and  Chloride  of  Iodine,  by 
D.  Gernez 318 
On  the  Mean  Motions  of  Jupiter,  Saturn,  Uranus,  and  Neptune, 
by  Professor  Daniel  Kirkwood 320 
NUMBER  CCLXXXVII.— MAY. 
The  Hon.  J.  W.   Strutt  on  the  Reflection  and  Refraction  of 
Light  by  intensely  Opaque  Matter    321 
Prof.  P.  G.  Tait's  Reply  to  Professor  Clausius    338 
M.  C.  Szily  on  Hamilton's  Principle  and  the  Second  Proposition 
of  the  Mechanical  Theory  of  Heat    339 
Prof.  C.  A.  Young  on  Recurrent  Vision   343 
M.  F.  Zollner  on  the  Origin  of  the  Earth's  Magnetism,  and  the 
Magnetic  Relations  of  the  Heavenly  Bodies 345 
-Prof.  A.  Cayley  on  a  Bicyclic  Chuck     365 
Dr.  H.  Emsmann  on  a  Collector  for  Frictional  Electrical  Ma- 
chines     368 
M.  G.  Quincke  on  Electrolysis,  and  the  Passage  of  Electricity 
through  Liquids 369 
Notices  respecting  New  Books  : — ■ 
Mr.  P.  Frost's  Elementary  Treatise  on  Curve-Tracing    . .    376 
Mr,  J.  B.  Smith's  Arithmetic  in  Theory  and  Practice. .  . .    377 
Mr.  J.  Harris's  Kuklos,  an  Experimental  Investigation  into 
the  Relationship  of  certain  Lines 379 
