724 



SCIENCE. 



[N. S. Vol. XIX. No. 



Professor of chemistry in the University of 

 Berlin; author of some epoch-making discoveries 

 in physical chemistry and of numerous contribu- 

 tions to chemical literature, including ' Lectures 

 on Theoretical and Physical Chemistry,' ' Studies 

 in Chemical Dynamics,' ' Chemistry in Space,' etc. 



Wilhelm Waldeyer, Berlin. 



Beetor magniflcus of the university and pro- 

 fessor of anatomy at Berlin; eminent anatomist 

 and author of numerous contributions to the 

 literature of anatomy. 



Afternoon Session — 2 o'clock. 



President Smith in the chair. 

 A System of Passenger Car Ventilation: 



Dr. Charles B. Dudley, Altoona, Pa. 



During the last ten years there has been 

 developed by the various experts of the 

 Pennsylvania Railroad Company, a system 

 of passenger car ventilation, which bids fair 

 to prove a reasonably successful solution of 

 this difficult problem. The system in brief 

 consists in taking air from the outside in 

 through hoods covered with wire gauze to 

 exclude coarse cinders, situated at diag- 

 onally opposite corners of the car, on what 

 is known as the lower deck, near the top 

 of the car. Thence the air passes through 

 a vertical down-take through the floor to 

 a space underneath the floor, which is 

 bounded by the outside sill, the floor, the 

 first intermediate sill, and the false bottom. 

 This space underneath the floor, reaches 

 the whole length of the car. From this 

 space the air passes up through the floor, 

 by means of slots in the floor, into the 

 heater boxes where the air is warmed by 

 the radiators. From the heater boxes the 

 air passes out through a proper tubular 

 aperture, situated underneath each seat, 

 into the main aisle, from which point it 

 distributes itself throughout the car, and 

 finally passes out of the car through venti- 

 lators situated along the center line of the 

 upper deck, which ventilators are so ar- 

 ranged that when the car is in motion, or 

 the wind blows across the top of the car, 



they produce a suction on the car, helping 

 to exhaust the foul air. 



The amount of air taken through the car 

 by the system when all the ventilators are 

 open is about 60,000 cubic feet per hour, 

 or approximately 1,000 cubic feet of fresh 

 air per passenger. A passenger coach 

 embraces about 4,000 cubic feet of space, 

 so that the air in the car is changed fifteen 

 times an hour. 



The experiments indicating the amount of 

 air as above were made with cars in motion 

 in a train, and with heat in the cars. The 

 control of the system is in the ventilators in 

 the upper deck. By closing the valves in 

 these ventilators, it is possible to diminish 

 the amount of air under the same condi- 

 tions as above to about half or a little more. 

 This diminution applies during extreme 

 cold weather, or when there are only a few 

 passengers in the car. When the car is 

 standing still, and there is heat in the car, 

 nearly half the amount of fresh air that is 

 obtained under full movement still passes 

 through the ear. When the car stands 

 still, with no heat in the car and no lamps 

 lighted, the amount of ventilation is still 

 more diminished. Thus far no serious 

 difliculties have been experienced in keep- 

 ing the ears warm, even in the most severe 

 weather, with the system of heating for 

 which the ventilating system was devised, 

 and the results have proved so satisfactory 

 that the system has now been applied to 

 about 800 passenger coaches on the Penn- 

 sylvania system east of Pittsburgh and 

 Erie, and to nearly 200 coaches on the 

 Pennsylvania lines west of Pittsburgh ; also 

 to some few cars on other railroads. It has 

 not yet been applied to Pullman cars. 



Atmospheric Nucleation: Professor Carl 



Barus, Providence, R. I. 



There is considerable probability that 

 material emanations from the sun enter 



