28 Count Rumford’s Account of a curious Phenomenon 
in the immense masses of solid and compact ice which compose 
the Glaciers of Chamouny ? 
A remark, which surprised me not a little, has been made by 
a gentleman of Edinburgh, (Dr. Thomson,) on the experi- 
ments I contrived, to render visible the currents into which 
liquids are thrown on a sudden application of heat, or of cold. 
He conceives, that the motions observed in my experiments, 
among the small pieces of amber which were suspended in a 
weak solution of potash in water, were no proof of currents 
existing in that liquid ; as they might, in his opinion, have been 
occasioned by a change of specific gravity in the amber, or by 
air attached to it. I am sorry that so mean an opinion of my 
accuracy as an observer should have been entertained, as to 
imagine that I could have been so easily deceived. For nothing 
surely is easier, than to distinguish the motion of a solid suspended 
in a liquid of the same specific gravity, which is carried along 
by a current in the liquid, from that of a body which descends, 
or ascends, in the liquid, in consequence of its relative weight, 
or levity. In the one case, the motion is uniform ; in the other, 
it is accelerated. In a current, the body may be carried forward 
in all directions, and even in curved lines ; but, when it falls in 
a quiescent fluid, by the action of gravity, or rises, in conse- 
quence of its being specifically lighter than the fluid, it must 
necessarily move in a vertical direction. 
The fact is, that I very often observed, in the course of my 
numerous experiments, the motions of small particles of matter, 
of different kinds, in water, which Dr. Thomson describes; 
but. so far from inferri ngfrom them the existence of currents in 
that fluid, their cause was so perfectly evident, that I did not 
even think it necessary to make any mention of them. 
