Nipher — Frictional Effect of Railway Trains upon the Air. 219 



The matter having now ceased to be a subject of judicial 

 consideration, it will not be indelicate to publish the results 

 of experiments upon which the evidence was based, and which 

 could have little meaning to a jury. This seems now to be 

 doubly important as a matter of public safety by reason of 

 the opinion of the court, that the danger here pointed out 

 does not exist. 



Jt may first be explained, that, although probably more 

 common than is supposed, such accidents are not very com- 

 mon. No person of mature years, and unfamiliar with train 

 effects, would voluntarily place himself as near a moving train 

 at high speed, as is necessary to result in danger. The 

 danger comes when one not familiar with trains is taken by 

 surprise, and becomes terrified. Trainmen think nothino- of 

 standing on the ground between a stationary train and one 

 passing at full speed. They know exactly what to expect 

 and they even unconsciously prepare for it. They habitually 

 take risks as great as those of war. But one who is surprised 

 in such a position, and who fears for the result, is in serious 

 danger. He should lie down or get upon his hands and 

 knees, in which position he will be safest. All four-footed 

 animals, particularly if they are small, are also on a stable 

 base, and are therefore in comparative safety. 



The differential anemometer before described is not easily 

 calibrated for precise measurements on account of the 

 element of friction. It was therefore determined to make 

 a direct measurement of pressure due to the velocity of the 

 train, at various distances from the train. For this purpose a 

 hollow cylinder of brass served to collect the pressure. 

 The open end of this tube 

 collector was directed to- 

 wards the head of the train, 

 and the wind pressure in the 

 collector was carried through 

 a small hole in the bottom 

 by means of a rubber tube, 

 to a water gauge in the car. 

 This gauge consisted of a closed cistern of water, having an in- 

 clined glass tube leading out from the bottom . The air pressure 



Fig. 2. 



