C «3 3 
III. An Account of a curious Phenomenon observed on the Glaciers 
of Chamouny ; together with some occasional Observations con- 
cerning the Propagation of Heat in Fluids. By Benjamin Count 
of Rumford, V. P. R. S. Foreign Associate of the National 
Institute of France , &c. &c. 
Read December 15, 1803. 
In an excursion which I made the last summer, in the month 
of August, to the Glaciers of Chamouny, in company with 
Professor Pictet of Geneva, I had an opportunity of observing, 
on what is called the Sea of Ice, ( Mer de Glace,) a phenomenon 
very common, as I was told, in those high and cold regions, but 
which was perfectly new to me, and engaged all my attention. 
At the surface of a solid mass of ice, of vast thickness and extent, 
we discovered a pit, perfectly cylindrical, about seven inches in 
diameter, and more than four feet deep; quite full of water. 
On examining it on the inside, with a pole, I found that its sides 
were polished ; and that its bottom was hemispherical, and well 
defined. 
This pit was not quite perpendicular to the plane of the 
horizon, but inclined a little towards the south, as it descended; 
and, in consequence of this inclination, its mouth or opening, at 
the surface of the ice, was not circular, but elliptical. 
From our guides I learnt, that these cylindrical holes are 
frequently found on the level parts of the ice; that they are 
formed during the summer, increasing gradually in depth, as long 
