On the Conduction of Water. 151 
Arr. XIII.—Conduction of Water; by Prof. Cuester Dewey. 
Ir is admitted, in opposition to the dogma of Count Rumford, that 
water slowly conducts caloric from particle to particle. To prove 
this fact it was thought necessary to show that caloric would pass 
downwards, if it was applied at the surface. The experiments have 
been of three kinds ; a thermometer is immersed in water, on whose 
surface hot oils are carefully poured, or ether or alcohol is burned, 
or a hot bar of iron held over it. In all these cases, the thermom- 
eter indicates a rise of temperature, and it is inferred that the calo- 
ric has been conducted downwards. Now, is not more attributed to 
these experiments, than they are known to prove. Is it certain that 
the caloric does not pass downwards by radiation, when a hot iron 
is held over the water or when hot oils are on its surface, for in cool- 
ing these would radiate caloric upwards, and where is the proof that 
a portion may not be radiated downwards? and thus also, when a li- 
quid is burned on the surface. Again, is it ascertained for a cer- 
tainty, that the chief part of the result is not dependent upon the 
conduction of the caloric downwards and along the sides of the ves- 
sel? That in glass vessels, something may depend on this, no one 
will be disposed to deny. If we are pointed to Dr. Murray’s exper- 
iments in vessels of ice, the reply is that they touch not the case of 
other vessels and prove not the point in theirown. For, the water 
will have the temperature of the ice, viz. 32°, Fah., and will be 
lighter than water at any temperature below 40°. Of course, when 
hot oils are put on the surface, the water in contact with the oil will 
have its temperature raised, and therefore be heavier, and sink to the 
thermometer, and thus raise its temperature without affording the 
slightest proof of the conduction of the caloric from particle to par- 
; The experiments of Dr. Murray are a complete failure, un- 
less the temperature of the water is preserved above that of 40°. 
And what is further to be noticed also, the less the water does con- 
duet or the more perfectly it retains the caloric received from the 
oil, the more quick and striking will be the rise of the thermometer, 
and the more complete the deception in the experiments. In this 
way, therefore, it cannot be proved that much of the result in com- 
mon vessels is not dependent upon the passage of caloric along the 
sides of the vessel. Although all these experiments are so defec- 
tive, there is yet full proof by a familiar experiment of the conduct- 
