856 



THE POPULAR SCIENCE MONTHLY. 



2,845 than in 1SSS-'S9, and greater by 2,627 

 than in ISS'Z-'SS. The number of casualties 

 to passengers was 255 greater than in 1888- 

 'S'J, and 258 greater than in ISSV-'SS. In each 

 class the number killed is about one tenth of 

 the number injured. The largest number of 

 casualties occur to employes engaged di- 

 rectly in handling trains. Thus, while train- 

 men represent but 20 per cent of the total 

 number of employes, the casualties sus- 

 tained by them account for 58 per cent of 

 total casualties. A passenger riding contin- 

 uously at the rate of 30 miles an hour might 

 expect immunity from death by railway ac- 

 cident for 158 years; but an engineer, a 

 brakeraan, or a conductor, under the same 

 conditions, is liable to a fatal accident at the 

 expiration of 35 years. The most common 

 accident to which railway employes are 

 liable results from coupling and uncoupling 

 cars. Railway travel is found to be least 

 safe in the States south of the Potomac and 

 Ohio Elvers. In the Western territory rail- 

 way employment and travel are slightly 

 safer than in the Southern States, while the 

 smallest proportion of accidents occur in the 

 States east of Illinois and north of the Poto- 

 mac and Ohio. 



Th? Power of Water in Motion. — After 

 an elaborate series of computations. Prof. 

 Samuel B. Christy, of the University of 

 California, concludes that if a nozzle of from 

 six to nine inches diameter were specially 

 arranged to throw a stream of water verti- 

 cally upward against a spherical bowlder of 

 quartz weighing 1,000 pounds, the vertical 

 head being anywhere from 100 to 500 feet, 

 the bowlder would be forced up until the di- 

 minished velocity of the stream established 

 an equilibrium of pressures. There would 

 be a point at which the upward pressure of 

 the stream would exactly balance the gravity 

 pressure of the bowlder, holding the rock 

 suspended. In practice, of course, the bowl- 

 der could not be balanced accurately upon 

 the axis of the stream, but would fall to one 

 side or the other. But if a large conical 

 basket of iron bars were arranged about the 

 nozzle so as to catch the bowlder whenever 

 it should be deflected from the stream, and 

 return it to the nozzle, the 1,000 pounds of 

 quartz would be kept in play like a ball in a 

 fountain. As to cutting these streams. Prof. 



Christy says that he has often tried to drive 

 a crowbar into one of them. The stream 

 felt as solid as a bar of iron, and, although 

 he could feel the point of the crowbar enter 

 the water for perhaps half an inch, the bar 

 was thrown forward with such force that it 

 was almost impossible to retain it in the 

 grasp. An axe swung by the most power- 

 ful man could not penetrate the stream ; 

 yet, it might be cut by the finger of a child, 

 provided the child were seated in a railway 

 train moving parallel with the stream in the 

 same direction and with the same velocity, 

 which would be considerably more than a 

 mile per minute. 



Chinese Roads. — According to a com- 

 munication by the United States minister in 

 Pekin, road-making has not been brought to 

 great perfection among the Chinese. The 

 country abounds in water-ways, and roads 

 receive the less attention. Human carriers 

 being cheaper than beasts of burden, the 

 need of roads over the mountain passes Is 

 not so seriously felt as it otherwise would 

 be. In southern China, at the centers of 

 the tea trade, the long string of coolies 

 bearing down from the hills the leaves, in 

 deep baskets slung on poles, is a familiar 

 sight. In northern China, where water-ways 

 are not so numerous as in the south, inter- 

 communication has always presented serious 

 difficulties, which no attempt has been made 

 to overcome. Bridges have been built over 

 some smaller streams, but are not kept in 

 repair. The large rivers are to be crossed 

 by ferries only, the smaller ones to be forded. 

 In some places there are bridges, too narrow 

 to be crossed by carts, where the mules are 

 taken out and led singly, while the carts are 

 carried over on men's shoulders. In times 

 of flood there is frequently no way of cross- 

 ing. Intelligence is conveyed between the 

 capital and outside provinces by an elaborate 

 system of post stations thirty miles apart, 

 where relays of horses are kept in readi- 

 ness for the imperial courier. By these 

 means dispatches have been sent to distant 

 capitals at the rate of two hundred and fifty 

 miles a day. The express courier from Gar- 

 tok to Lhara, in Thibet, a distance of eight 

 hundred miles, travels night and day, and is 

 not relieved. His clothes are sealed on him, 

 and can be removed only after the seal has 



