496 Scientific Intelligence. 



known by the Canadian geologists, Bailey, Matthew and Ells, 

 in New Brunswick.* Bell has also recentty described similar 

 rocks in the Sudbury region. f 



Similar areas are easily recognizable in Canada and Maine 

 from the writings of Hunt, Jackson and Hitchcock, in spite of 

 the fact that they are not properly interpreted. Volcanic 

 rocks have not before been clearly identified in the Appalach- 

 ians, but if attention is called to them they will doubtless be 

 recognized at many other points. 



Petrographical Laboratory, 

 Johns Hopkins University, Nov. 1, 1892. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Temperature of Steam from JB oiling Salt-solutions. 

 Considerable diversity of opinion exists on the question of the 

 temperature of the vapor arising from boiling salt-solutions. Cer- 

 tain observers, as Faraday, Wullner and Magnus, maintain 

 that this temperature is the same as that of the solution, while 

 others, as Rudberg and Miiller, hold the opinion that it is practi- 

 cally the same as that arising from water, boiling uuder the same 

 pressure. In order to settle the question Sakurai has made a 

 series of experiments in which certain sources of error incident to 

 previous methods of investigation were avoided. His apparatus 

 consisted of a long necked flask containing the solution, through 

 the stopper of which two thermometers passed, one with its bulb 

 in the solution the other with its bulb in the vapor above it. The 

 neck of this flask was surrounded with a jacket, into which vapor 

 could be passed from a boiler, and which was connected with a 

 condenser. A third thermometer indicated the temperature in 

 the jacket. Through a tubulure in the side of the flask, steam 

 was blown in order to supply sufficient vapor to maintain the tem- 

 perature in the neck, the excess of vapor passing off through a tube 

 in the stopper. The solution to be examined was placed in the 

 flask without soiling the neck, the stopper was inserted, a solution 

 of acetic acid boiling at a slightly lower temperature than the 

 solution was placed in the boiler and made to boil, and the gas 

 was lighted under the flask. When the solution was heated to 

 boiling, steam was admitted through the lateral tubulure and the 

 whole being in equilibrium, the temperature of the thermometer 

 was read. With a dilute solution of calcium chloride, the tem- 

 perature of the solution varied from 112-5° to 113-3°, that of the 

 jacket from 110-8° to 111:9° and that of the vapor from 111-2° to 



*Ann. Sep. Can. Geol. Surv., 18T7-8 DD, and 1879-80 D. 

 flbid., for 1889-90 F, 1891. 



