106 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



its different states of combination, which the author is now 

 engaged in measuring. 



Hesehus lias applied the electric current to the study of 

 the spheroidal state of liquids. He finds (1) that this cur- 

 rent is generally completely interrupted between the incan- 

 descent metal and the liquid spheroid, and that when it is 

 not, this is due either to the fact that the liquid is in motion, 

 and thus establishes momentary contacts, or that, the tem- 

 perature of the metal being low, the drop is ready to burst; 

 (2) that the interval separating the two estimated by the 

 galvanic deposition of copper is about one tenth of a mil- 

 limeter, though it increases with the temperature ; and (3) 

 that the temperature of the liquid, as measured by a thermo- 

 pile, does not vary much from 96 to 97 C. 



Bruhns has given a description of a new psychrometer and 

 barometer devised by Bogen, of Chili. The former is a 

 modification ofRegnault's instrument, only instead of using 

 the evaporation of ether to cool the bulb, the solution of 

 ammonium nitrate in water is made use of. The peculiarity 

 of the barometer consists in the method of filling, which is 

 said to be very simple. It is the subject of a patent. 



Garnett has described the method pursued in the Caven- 

 dish Laboratory, Cambridge, of exhibiting the phenomena 

 of the passage of a gas through its critical point upon a 

 screen in presence of a class. Dr. Andrews's apparatus was 

 used, the image of the tube containing the carbon dioxide 

 being projected on the screen with the calcium light, a mi- 

 croscopic objective enlarging it about 120 diameters. 



Plank has determined the conducting power for heat of 

 several gases. Calling that of air 1, that of nitrogen is 0.993 ; 

 that of nitrogen dioxide, 0.951 ; that of ammonia, 0.91V ; and 

 that of illuminating gas, 2.G70. 



Wiedemann has communicated an elaborate memoir on 

 the specific heats of gases, one object of the research being 

 to obtain as exact results as those of Regnault with less 

 complicated and costly apparatus. Besides air, the gases 

 examined were hydrogen, carbonic oxide, carbonic acid, 

 ethylene, nitrous oxide, and ammonia. The specific heats 

 correspond closely with Regnault's, though much more ex- 

 peditiously obtained. 



