Geological Society. 389 
On page 58, last two lines, ¢ and p should change places. The 
chapters are :—Refraction at a Single Surface, at Two Surfaces in 
Succession, at any Number of Surfaces; Achromatism; Deter- 
mination of the Foci and of the Principal Points, Nodal Points ; 
Different Forms of Lenses; with an Appendix on Continued 
Fractions. There are no numerical examples given to exercise 
the student. 
Transit Tables for 1885. By Latimer Cruarx, MW.LC.E., ge. 
London: Spon, 1885; pp. 71. 
Me. Latimer Cuark continues his useful work by bringing out 
a new Edition of his Tables, which we understand are now 
ordinarily employed at Kew Observatory in place of those of the 
‘Nautical Almanac.’ This year’s issue differs slightly from its 
predecessors, the times of transit being given to the nearest tenth, 
instead of, as previously, to the nearest hundredth, of a second. 
There is also an additional set of Tables, giving for each alternate 
day certain astronomical data, among others, the Sun’s semidiameter. 
The last would be much more conveniently placed immediately 
after the column containing the time of the Sun’s transit. The 
introductory matter contains much useful information as to the 
method of using the Transit instrument and obtaining true time 
in any part of the world. The book will prove a very useful 
adjunct to the private observatory. 
Electrical Units, their Relation to one another, and other Physical 
Units; with a Chapter on the Different Forms of Dynamos and a 
Series of Numerical Questions. By Dr, R. Wormett, M.A. 
London: Murby; feap. 8vo, pp. 48. 
Iy this, which is an Appendix to ‘Magnetism and Electricity’ by 
the same Author, there is a fairly lucid explanation of the various 
units in use in the science and of the manner in which they are 
connected. Several forms of Incandescent Lamps are described, 
as well as some of the Dynamos now most frequently used for the 
production of the Electric Light. The pamphlet concludes with 
a series of useful questions on Magnetism and Electricity generally. 
XLII. Proceedings of Learned Societies. 
GEOLOGICAL SOCIETY. 
{Continued from p. 229. ] 
February 25, 1885.—Prof. T. G. Bonney, D.Se., LL.D., F.R.S., 
President, in the Chair. 
HE following communications were read :—- 
1. “On a Dredged Skull of Ovibos moschatus.” By Prof. W. 
Boyd Dawkins, M.A., F.R.S., F.G.8. 
2. “On Fulgurite from Mont Blanc.” By Frank Rutley, Esq., 
F.G.S. 
The specimens described in this paper were collected by Mr. J. 
