196 WATER. [Lesson xxix. 



each other, and that when their temperature is 

 undergoing any change, an intestine faction is 

 kept up in them, by a successive alteration taking 

 place in the specific gravity of their particles, he 

 proceeds to shew, that " all bodies are condensed 

 (f by cold without limitation, Water only excep led," 

 and describes the wonderful effects produced in 

 consequence of this particular fact*. 



" Though in temperatures above blood-heat 

 (says the Count), " the expansion of Water with 

 " heat is very considerable, yet in ihe neighbour- 

 " hood of the freezing point it is almost nothing. 

 tl And what is still more remarkable, as it is an ex- 

 tl ception to one of the most general laws of nature 

 t( with which we are acquainted, when in cooling 

 " it comes within eight or nine degrees of Fahren- 



* The circnmstances of this remarkable anomaly have been 

 for some time believed to be the following: 



When heat is applied to water, ice cold, or at a tempera- 

 ture not far distant, it causes a diminution of the fluid. The 

 water contracts, and continues to contract, with the tempe- 

 rature, till it reaches the 10th or 41st degree. Between this 

 point and the 42d or 43d, it suffers scarcely any perceptible 

 change ; but when heated beyond the last-mentioned degree, 

 it begins to expand, and increases in volume with every sub- 

 sequent rise of temperature. 



During the abstraction of heat, the peculiarity in the con- 

 stitution of water equally appears. Warm water, as it cools, 

 shrinks, as other bodies do, till it arrives at the temperature 

 of 43 r or 42. It then suffers a loss of two degrees without 

 any alteration of density. But when farther cooled, it begins 

 to dilate, and continues to dilate, as the temperature falls, till 

 congelation actually commences, whether this occurs as soon 

 as the water reaches the 32, or after it has descended auy 

 number of degrees'below it. 



belt's 



