100 BULLETIN OF THE 



systems was alluded to. In the majority of such halls the plenum 

 system, by means of a fan, is used. The difficulty in introducing 

 this large amount of air into a hall depends partly on the neces- 

 sity for avoiding unpleasant currents, and partly on the cost of 

 heating and supplying power. The question of cost, however, in 

 such halls as are referred to, is # usually a minor consideration, but 

 if the tastes of individuals as to temperature are to be consulted — 

 that is, if each man is to have his air at the temperature which 

 suits himself — the cost becomes a serious matter. 



The effects of various positions of fresh air inlets were pointed 

 out, and stated to depend largely upon the tendency of air to ad- 

 here to surfaces over which it passes, as shown by the investiga- 

 tions of Savart and others. The difference between the upward 

 and downward system were pointed out. 



The various modes of heating were described, more especially 

 with reference to their effect upon the air, and the influence of 

 moisture was discussed. Probably the importance of moistening 

 the air is less than has been supposed, and the methods employed 

 for this purpose have been beneficial only indirectly. 



The system of heating and ventilation of the Hall of the House 

 was then described, and compared with that of the English Houses 

 of Parliament, the Chamber of Deputies at Versailles, and the 

 Grand Opera House at Vienna, and Frankfort on Main. 



The great importance of skilled superintendence was pointed out, 

 and the necessity for continuous records was insisted on. 



Remarks upou this communication were made by Messrs. Anti- 

 sell, Elliott, Museey, and Powell. 



Mr. Hilgard then presented a communication 



ON SIEMENS' DEEP SEA THERMOMETER AND CARRE'S ICE MACHINE. 



Remarks on this communication were made by Messrs. Anti- 

 sell, Dall, Dutton, and E. J. Farquhar, after which the So- 

 ciety adjourned. 



216th Meeting. April 22, 1882. 



President Wm. B. Taylor in the chair. 

 Thirty-six members and visitors present. 

 The Secretary read a list of names of persons who had been 



