150 ANNUAL OF SCIENTIFIC DISCOVERY. 



the limits above mentioned, was found to be 0.48. In determining tho 

 latent heat, the ice was formed into cylinders, in the axis of which 

 were placed thermometers showing T^th degree ; the time of fusion 

 in the calorimeter was on the average about 12 minutes. It was found 

 that the latent heat of fusion of ice was very nearly constant, setting 

 out from a temperature of 2, and was then represented by 79.97. 

 From this it may be inferred that ice approaches very near its point of 

 fusion without sensibly changing its consistence, the slight softening 

 which precedes the fusion being comprised within an interval of two 

 degrees ; the passage of ice from a solid to a liquid state, though suf- 

 ficiently well defined, is still effected by degrees, and not abruptly. 

 De la Provostaye and Dessains on the one hand, and Regnault on the 

 other, had found, for the latent heat of ice, the number 79 ; the experi- 

 ments of Regnault had, however, clearly shown that this number was 

 not constant, but increased as the initial temperature of the ice dimin- 

 ished at least as far as 0.61, for which the corresponding latent heat 

 was 79.71. Ann.de Chimiect de Physique, Sept. 1850. 



EFFECTS OF PRESSURE ON THE FREEZING OF WATER. 



AT a meeting of the American Philosophical Society, Prof. Crenon 

 made some remarks on the experiments of Prof. Thomson, and which 

 Prof. Thomson believes to show that the temperature of congelation of 

 water and other bodies that expand, at the moment of solidification, is 

 raised proportionably to the increase of pressure to which they are sub- 

 jected the ratio of temperature to pressure being in water 1.10 of a 

 degree of Fahrenheit's scale, in ten additional atmospheric pressures. 

 Mr. Crenon presented to the notice of the society a speculation into 

 which he had been led on the subject, showing the effect that such a 

 law might produce in causing water to retain the state of a solid, at a 

 very high temperature. For example, if a continuous channel, admit- 

 ting atmospheric communication, should exist in the crust of the earth 

 to the depth of seventy miles, the pressure of the atmospheric column 

 would exceed fifteen million pounds on the square inch ; and, accord- 

 ing to Professor Thomson, water would remain solid at a temperature 

 above 10.000 Fahrenheit a heat far above that of molten iron. 



ON THE INTENSITY OF SOUND IN THE RAREFIED AIR OF HIGH MOUNTAINS. 



IN the Edinburgh Philosophical Magazine, for Jan., 1851, M. Martins 

 communicates the results of various experiments, made with a view of 

 determining the intensity of sound in rarefied air. 



The intensity of sound depends on the density of the air at the place 

 of the primitive disturbance, and not on that of the strata traversed by 

 it, nor on that of the air surrounding the hearer. This was proved in 

 the course of experiments made with two mortars, upon the velocity 

 of sound ascending and descending, the mortars being of the same 

 fount, the one placed upon the summit of a mountain, and the other 

 below. It was found that, with the same charge, the sound created in 

 tho air, at an altitude of 2082 metres, was much weaker than that 



