559 
of Edinburgh, Session 1874-75. 
Kohlrausch Las already corrected his first results to be made 
“perfectly satisfactory.” We might therefore congratulate our- 
selves on having made so close an approximation, and proceed to 
lighten our mirror. Whether or not, however, it must be much 
or little or at all lightened, is a question which must be regarded 
as not yet settled. It may be that Professor Beetz’ results are 
accurate, and that ours alone need correction, but that is not 
proved ; and, in the meantime, it will be well to hold to the 
acknowledged truth that neither accuracy nor error is often found 
to be all on one side. 
Professor Beetz “would not have pointed ouF the weak points 
of our paper in so searching a style, had we not conducted the 
experiments under the guidance of Professor Tait,” who, in com- 
municating it for us to the Boyal Society, took upon himself, he 
thinks, the responsibility for its contents. He did so, at the very 
least, to the same extent as is always done by the secretary of a 
learned Society who communicates a paper not written by a Fellow. 
The remarks which I have offered will, I venture to think, shew 
the responsibility to be a lighter matter than Professor Beetz 
supposes. If our errors were as numerous as his accusations there 
would certainly be a great deal to answer for. But fortunately the 
strength of the arguments on which he bases them is inversely as 
the strength of language in which he expresses them ; and as the 
latter is great, so the former is small. 
Monday , 7 th June 1875. 
DAVID STEVENSON, Esq., Vice-President, in the Chair. 
The following communications were read : — 
1. On High Flood Marks on the Banks of the Eiver Tweed 
and some of its tributaries, and on Drift Deposits in 
Tweed Valley. By David Milne Home, LL.D. 
In many parts of Scotland there are indications that our exist- 
ing rivers reached much higher levels than at present, and that 
