866 



Popular Science Monthly 



''turbine discharge accelerator," because 

 it can accelerate the flow of water 

 through a turbine water-wheel. It is 

 adjustable, and it can readily be regu- 

 lated to the river conditions. 



The illustrations will give a general 



This household size apparatus will sterilize 

 one thousand gallons of water for five cents 



idea of the new device. The results 

 were so marked as to appear incredible. 

 Some of them are as follows: 



1. The turbine w'heel can be made 

 to develop its normal rated power at 

 half head. 



2. The turbine wheel can be caused 

 to develop nearly double its rated 

 l)ower at its normal head. ( It will, of 

 course, use more water in both cases). 



3. The turbine can be made to 

 develop a fair amount of power at 

 proper speeds, when the head seems 

 to be almost totally destroyed by high 

 water. The latter conditions are 

 extreme and are not often met in 

 practice. 



Sterilizing Water by Ultra 

 Violet Light 



ULTRA violet light is not visible to 

 the eye, yet it affects a photograph- 

 ic plate, decomposes many chemicals, 

 causes sunburn and sunstroke, and 

 kills bacteria. Nature's purification of 

 rivers owes something to the ultra 

 \iolet portion of the sun's rays. A\ hy 

 not use it to purify drinking water? 

 That idea has actually been carried out 

 at Saint Malo, at Rouen and at Lune- 

 ville, all in France. 



The best commercial source is the 

 mercury arc in which mercury vapor 

 in a high vacuum becomes luminous 

 as it conducts the electric current. The 

 ultra violet cannot pass through the 

 glass. Hence, the lamp tube must be 

 made of clear quartz, one of the few 

 solids transparent to these rays. 



The light tube is a "pistol lamp," as 

 it is called, because it is bent into a U- 

 shape and enclosed in a quartz jacket as 

 a protection against the cooling eft'ect 

 of the water. The pistol tube is im- 

 mersed in the flowing water while the 

 connections are outside the tank. 



The capacity of apparatus now in the 

 market varies from twenty gallons an 

 It our to ten thousand gallons an hour or, 

 hv increasing the number of units, to any 

 figure for large city water plants. An 

 experimental plant in one American 

 city forces the water through concrete 

 channels two feet wide, three feet deep 

 and twenty-six feet long, affording a 

 contact period of thirtv seconds with 

 the ultra violet rays. The pistol lamps 

 are spaced thirty inches apart, and in 

 front of each is a baffle of wnred glass 

 in which a rectangular opening is cut 

 to divert the water against the quartz 

 tube. 



The smaller types are used in steril- 

 ization of drinking water for homes, 

 clubs, hospitals, factories, etc., purify- 

 ing swimming pools, sterilizing water 

 for ice plants and can even be found 

 with armies in the field. The Austrian 

 army carries a portal)le type on a motor 

 car. In five minutes after starting the 

 generator the soldiers fill their canteen 

 with sterile and palatable drinking water. 

 Tlie household size is efficient and ec- 

 onomical. 



