Correspondence—Bernard Smith. 45 
of the problem of Four Tautozonal Poles. The indices of two poles 
C, D may be expressed as functions of those of the two other A (adc), 
B (def) in the form (pa+qd, pb+-ge, pe+ qf), (ma+nd,mb+-ne, me+nf) 
where p, g, m, m are small positive or negative integers. Since 
npcot A D=(np-mq)cotAB+mqcot AC, a table of natural cotangents 
enables a numerical example to be solved rapidly. Usually p=q=1, 
and the equation reduces to ncotAD=(n-m)cotAB-+ mcot AC. 
L. J. Spencer: Crystals of Iron Phosphide (Rhabdite) from a Blast- 
furnace. The small, acicular, tin-white, and strongly magnetic 
erystals were found sparingly in cavities in a large mass of 
metal at the bottom of a blast-furnace near Middlesbrough. They 
are tetragonal (sphenoidal -hemihedral) with the axial ratio, 
-@:c=1:0°3469. Dr. G. T. Prior: The Meteoric Stone of Cronstad 
Orange Free State. 
At the above meeting the following officers and members of Council 
were elected: President, W. Barlow, F.R.S.; Vice-Presidents, Professor 
H. L. Bowman and A. Hutchinson; Treasurer, Sir William P. Beale, 
Bart., K.C., M.P.; General Secretary, Dr. G. T. Prior, F.R.S.; 
Foreign Secretary, Professor W. W.- Watts, F.R.S.; Editor of the 
Journal, L. J. Spencer; Ordinary Members of Council, Dr. J. J. Harris 
Teall, F.R.S., F. N. Ashcroft, Professor H. Hilton, Arthur Russeli, 
W. Campbell Smith, Dr. J. W. Evans, Dr. F. H. Hatch, J. A. Howe, 
T. VY. Barker, G. Barrow, Dr. C. G. Cullis, and F. P. Mennell. 
CORRESPON DHNC#. 
‘ON CERTAIN CHANNELS.” 
Srr,—A section of Professor Bonney’s recent essay On certain 
Channels attributed to overflow streams from ice-dammed lakes! is 
devoted to an extremely courteous criticism, but final rejection, of 
_ my interpretation of glacial phenomena in the Black Combe area.’ 
Since he advances an alternative hypothesis to account for the above- 
mentioned channels, [ am sure he will pardon me if I, in my turn, 
offer a few critical remarks. 
I must first protest against Professor Bonney’s assumption (vede 
title of his paper) that I ascribe practically all these channels to 
overflow waters from ice-dammed lakes. In many cases, as I clearly 
state, they were merely carriers of the normal marginal drainage of an 
ice-sheet. Nor do I invent ice-dams ‘‘almost by the dozen’’. As 
regards overflows from lakes, one dam—the Irish Sea Ice—is quite 
sufficient. 
In my description the drainage channels are discussed and 
' interpreted in the light of observations, recorded on 6 in. field maps, 
and fall into place as an important chapter in the glacial history 
of the area. Professor Bonney states that he accepts most of my 
facts, but differs from my conclusions; yet, having made this 
admission, and agreeing that land*ice ‘‘occupied all this district 
during some part of the Ice Age’’, he appears to ignore the evidence 
1 Published by Bowes & eae Cambridge, 1915. 
2 Q.J.G.S., vol. Ixviii, 1912. 
