254 



DUDLEY — PASSENGER CAR VENTILATION. 



[April 8, 



fitted as above described was filled with men from the shops, who 

 were paid for their time, under the charge of a foreman, so that 

 they could be controlled in the matter of opening doors and 

 windows, and a trip was made early in December from Altoona to 

 Johnstown and return. Rubber bags and hand bellows were taken 

 along with which to secure samples of the air in the car. Steam 

 heat was necessary since the temperature outside was from 23 to 30 

 degrees Fahrenheit, and neither door nor window was opened dur- 

 ing the trip, except that after the proper samples of air had been 

 taken at Johnstown the men were allowed some freedom, since a 

 wait of a couple of hours must ensue before the return trip could be 

 made. The air samples for analysis were taken by pumping air into 

 the rubber bags by means of the hand bellows, moving from one 

 end of the car and back again in the aisle during the operation, and 

 taking the air from about the level of the heads of the passengers. 

 The analyses were made immediately after the return. In making 

 the air analyses the carbonic acid only was determined, and from this 

 was calculated the amount of fresh air taken through the car per 

 hour by the ventilating system, the method used being the one 

 described earlier in this article. As a matter of fact, there were 

 fifty-two men in the car, and being workingmen it was assumed 

 that they gave off 0.72 of a cubic foot of carbonic acid each per 

 hour. The figures obtained on the trip mentioned are as follows : 



Westbound. 



All Globe ventilators closed — Bennington 



All Globe ventilators open — Buttermilk Falls . . 



All Globe ventilators open — standing twenty 



minutes at Johnstown 



Eastbound. 



All Globe ventilators closed — Cresson 



All Globe ventilators open — McGarvey 



All Globe ventilators open — standing twenty 

 minutes at Altoona 



Cubic feet of 



air per car 



per hour 



26,700 

 62,400 



22,000 



37.400 

 62,400 



23,400 



