252 DUDLEY — PASSENGER CAR VENTILATION. [Aprils, 



made. Each experiment led to modifications and clianges, whicli 

 were followed often by runs on the road, with analyses of air from 

 the cars, the information obtained from each trial being used to 

 lead to further modification, until a satisfactory result was obtained. 

 Of course, the system as described is the one finally decided on. It 

 will be noted by an examination of the plate that, taken as a 

 whole, the system is extremely simple. It consists in taking air from 

 the outside in through hoods located on what is known as the lower 

 deck near the top of the car, and at diagonally opposite corners of 

 the car. The opening of the hoods is toward the direction in 

 which the car is moving, and, as will be noted a little later, the 

 movement of the car is an element in the problem of getting the air 

 into the car. The opening is covered with a gauze to exclude large 

 cinders. The hood is fitted with a valve operated from the inside 

 of the car in such a way that as the car changes direction the 

 proper passageway is provided. Frcm the hood the air passes 

 through what is technically called a ** down-take," about loo square 

 inches in area, which conducts the air down underneath the floor of 

 the car to a passageway which occupies the space between the out- 

 side sill, the floor, the first intermediate sill and the false bottom. 

 This space has an area of a little over loo square inches, and extends 

 the whole length of the car. From this space the air passes up 

 through apertures in the floor into the heater boxes, where it 

 is warmed. From the heater boxes the air passes out into tubes 

 situated under each seat, and is delivered into the aisle of the car 

 from the tubes. From these points it disseminates through the car, 

 and finally passes out of the car through ventilators situated along 

 the center line of the upper deck. These ventilators may be of any 

 approved form. The kind most used thus far has been what 

 is known as the ''Globe Ventilator," which ventilator has the 

 characteristic that when the car is moving through the air, or when 

 the wind is blowing across the ventilator, a suction is produced on 

 the air in the car. It will be observed from what has already been 

 stated, that there are two things that cause the ventilating air to 

 move through the car. First, the heating system. The ventilators 

 in the upper deck are situated some two feet higher than the top of 

 the hood, and accordingly, when there is heat in the car, or when 

 the lamps are lighted, there is the proper ventilating movement of 

 air through the car, due to this force. Also it will be noted that 

 the movement of the car is an element in the problem likewise. The 

 car movement produces pressure in the hood and down -take and the 



