XIV. Experiments <7k^ Observations upon the Contraction 

 0/ Water /J/ Heat at Low Temperatures. By "Thomas 

 Charles Hope, M. D. F. R. S. Ed. ProfeJJTor of Cbemifiry in 

 the Univerfity of Edinburgh. 



l^Read gth January 1804.] 



TO the general law, that bodies are expanded by heat, and 

 contra(3ed by cold, water at the point of congelation, and 

 for feme degrees of temperature above it, feems to aflford a very 

 fingular and curious exception. 



The circumftances of this remarkable anomaly have been for 

 fome time believed to be the following : 



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

 not far diflant, it caufes a diminution in the bulk of the fluid. 

 The water contra(5ls, and continues to contrad:, with the aug- 

 mentation of temperature, till it reaches the 40th or 41ft degree. 

 Between this point and the 42d or 43d, it fuffers fcarcely 

 any perceptible change ; but when heated beyond the lafl-men- 

 tioned degree, it begins to expand, and increafes in volume with 

 every fubfequent rife of temperature. 



During the abftraftion of caloric, the peculiarity in the con- 

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

 {brinks, as other bodies do, till it arrives at the temperature of 

 43 '^ or 42°. It then fuffers a lofs of two degrees without any 

 alteration of denfity. But when farther cooled, it begins to "di- 

 late 



