Intelligence and Miscellaneous Articles. 467 



ON THE CHANGES IN THE SPECIFIC HEAT OF LIQUIDS NEAR THE 

 CRITICAL TEMPERATURE. BY P. DE HEEN. 



The author used the method of cooling. The steel cooling- 

 vessel is half filled with the liquid in question, and in order to 

 produce a uniform temperature in the whole mass it rotates 

 about a horizontal axis. After being heated it is enclosed in a 

 copper envelope. For ether, amylene, and bromide of ethyle, there 

 was at the critical temperature a sudden diminution in the specific 

 heat. 



Temperature. Specific heat. 

 ml f 185 0-547 



Ether 1 ISO 1-041 



Amylene \ -. t-~ 



0-773 

 1-500 



-p ., , A , J22 0-233 



Bromide ot ethyle. < 



215 0-852 



"With aldehyde, which, however, decomposed, there were no ana- 

 logous phenomena. 



The author infers from the behaviour of the former substances 

 that as the critical temperature is reached the gas-forming mole- 

 cules relinquish their closed curves and describe the rectilinear 

 paths of Clausius. — Bull. Ac. Roy. cle Belg. [3] xv. pp. 522-528. 

 Beibldtter der Fhysik, Xo. 9, 1888. 



ELECTROSCOPE FOR PURPOSES OF DEMONSTRATION. 

 BY B. KOLBE. 



This electroscope, which has been specially constructed for pur- 

 poses of demonstration, is visible on a clear ground at a distance of 

 30 to 50 feet; and gives large deflections, for, when charged, the 

 leaves are almost horizontal. They consist of red silk paper, and 

 are hung in stirrups of fine silvered copper wire at the side of the 

 brass rod, the upper knob of which has a diameter of 2 centim. The 

 length of the leaves is 3*5 to 4 centim., and the breadth about 0-4 

 centim. The end is provided with a semicircular enlargement 

 which is twisted at right angles, so that it always presents a surface 

 to the observer. 



The conducting rod is insulated by a stout ebonite stopper. 



It is important to choose a glass which conducts well, in order to 

 get rid of the disturbing influence of the glass sides. Moreover the 

 glass vessel must be so spacious that the leaves, even when charged, 

 are at a distance of 0*5 to 1 centim. from the glass. If the glass 

 is not a good conductor, the vessel should be so wide that the leaves 

 (when horizontal) are at a distance of 2 to 2*5 centim. from the 

 glass. 



It appears hitherto to have been usual to take a good insulating 



