£38 Dr Traill on Thermo-Magnetism 
and so on successively, till the whole embankment is washed 
away, and the valley left as we now see it. 
The stones all bear the marks of having come from some dis- 
tance, and may possibly have been deposited by a river flowing 
fmm the snowy Andes in ancient times ; while some vast, though 
transient cause, may, at one operation, have scooped out the 
valley, filled it with water, and left a barrier of adequate strength 
to retain it for a time, till, by a succession of sudden disruptions 
of this barrier, the lake would stand at different levels, and the 
washing of the water down the sides of the banks, would bring 
along with it the loose stones to the water’s edge, where their 
velocity being checked, they would be deposited in the form of 
level beaches. In the Alpine valleys of Savoy, circumstances 
precisely analogous frequently occur, when a great avalanche 
dams up a stream, and forms a lake, which stands at different 
levels, as the barrier of ice successively breaks away 
Art. IV.- — On Thermo- Magnetism. By Thomas Stewart 
Traill, M. D,, &c. 
£The following is the substance of- a Paper which was read at two 
successive meetings of the Royal Society of Edinburgh, on Feb- 
ruary 2., and February 17 . 1324.] 
In the first part, the author detailed a long series of Thermo- 
magnetic experiments. The apparatus he employed consists of 
bars of antimony, bismuth, See. 4J inches long, \ inch broad, 
and J inch thick ; to which slips of copper, of the form ex- 
hibited in Plate X, Fig. 3. are united, by tying their extre- 
mities to the ends of the bars with fine copper-wire. This 
renders soldering unnecessary ; and, when the thenno-mag- 
net ism is diminished by the oxidation of the surfaces in con- 
tact, they are soon brightened by rubbing them with sand- 
paper, or a fine file, and easily replaced. 
This form of the apparatus was found very convenient for 
examining the thermo-magnetism of every surface of the com- 
pound metallic rectangle ; and the influence of different posi- 
* We observed a series of natural terraces along the sides of one of the basins 
fn the line of the Union Canal. We reckoned four or five of these, which were 
formed by the successive lowering of the water in the basin. Eon. 
