223 
to Delaunay’s criticisms in some letters published in Nature; 
and read an extract from the last of these. He asked whether 
it was true that the axis of the fluid nucleus would not be 
affected by the motion of the shell of the earth, and whether it 
would not drag upon the fluid interior. 
Mr Rours replied that it would drag. 
Professor STOKES said that a hollow sphere with a perfect 
fluid within would pass over the fluid without dragging, whereas 
a very viscous fluid would follow that sphere; therefore it was 
entirely a question of degree. 
Professor CAYLEY enquired whether Mr Réhrs had examined 
Delaunay’s paper, in which he accounted for the difference be- 
tween the observed and calculated time of ancient eclipses by 
a retardation leading to an alteration in the length of the day. 
‘Professor STOKES made a few remarks on the mode of 
attempting the problem in the former of Mr Réhrs’ commu- 
nications. 
May 29, 1871. 
The PRESIDENT (PROFESSOR CAYLEY) in the Chair. 
Fellow elected : 
M. Foster, M.A., M.D., Trinity. 
Honorary Members elected : 
Prof. Sir BENJAMIN CoLLINS Bropig, M.A., F.R.S. 
W. B. Carpenter, M.D., F.RS. 
A. R. CLARKE, Capt. R.E., F.R.S. 
Prof, T. Huxuny, M.D., E-B.S. 
Prof. BARTHOLOMEW Prics, M.A., F.R.S. 
WILLIAM SPOTTISWOODE, M.A., Treas. R.S. 
Prof. F. W. A. ARGELANDER (Bonn). 
Prof. A. CLEBScH (Gottingen). 
Prof. A. O. DES CLOISEAUX (Paris). 
Prof. H. HetmHouz (Berlin). 
Prof, F. W6HLER (Gottingen). 
