. 
354 Count Rumford on ha. aHA%-% 
flichofout reidasiss hare dot feeh-the Count’ s Effays; of 
who, from their numerous avocations, cannot {pare time to 
read a more voluminous accoutit. 
In the courfe of a fet of experiments, in which the Count. 
had occafion-to ufe thermometers of an uncommon fize, 
(their bulbs being above 4 inches in diameter) having €x- 
pofed one, filled with fpirit of wine, in a window, to cool 
after being heated, he obferved the whole mafs of liquid in 4 
moft rapid motion, running {wiftly in two oppofite direc- 
tions wp and doy at the fame time. This motion was ren- 
dered vifible by fome particles of duft which had got by ac- 
cident among the fpirit of wine, the fun happening to fhine 
upon the window, as duft in the air of a darkened room is 
vifible by the fun-beams coming through a hole in the 
window-fhutter. The afcending current occupied the axis 
of the tube, the defeending the fides. . On inclining the tube 
alittle, the former moved out of the axis and occupied that 
fide which as uppermoft, the latter the whole of the lower 
fide. Quick cooling, by applying ice cold water to the tube, 
increafed the velocities of the currents, which, however; 
ceafed entirely when the thermometer had acquired the 
‘temperature of the room. 
Being perfuaded that this motion in fluids (for the: fame 
experiment was tried with the fame refult with a fimilar 
thermometer filed with linfeed-oil*) was occafioned by 
their particles going individually-and in fucceffion to give off 
thiir lieat, to the cold fides of -the tube, the Count was led 
to conclude, that fluids are in fact non-conduétors of heat ; 
and that, if heat be propagated in them only in confequence 
of the internal motion of the particles, whatever could ob- 
* The fame motions were rendered vifible in water by mixing powdered 
amber with it, which is nearly of rhe fame fpecific gravity, being 1°078, 
while that of rhe former is 1-000, Potath was added to the water till it 
tecam 
: i ; HY ofthe lian Gece sek “ 
remaibed-ftationary in any part of the liquid, ualefs when the particles of 
lan 5 A a 
ecf the fame gravity wich the amber, the particles ‘of which then 
the latter were put ia motion by any fudden change os temperature: 
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