STERILIZATION OF DRINKING WATER COURMONT. 243 



We have obtained similar results as to oxygenated water. 1 Cer- 

 tain investigators have thought that this was produced and caused 

 the sterilization and would itself render the water dangerous for 

 alimentary use. Such an explanation is false and the fear ground- 

 less. But a trace of oxygenated water was formed after several 

 hours' exposure to the rays. There was never any oxygenated 

 water formed during the short passage of the water about the lamp 

 necessary for the sterilization. 



CHEMICAL MODIFICATION OF THE WATER TREATED WITH THE ULTRA- 

 VIOLET RADIATION. 



Chemically water is very little altered by the ultra-violet rays, 

 certainly during the short time required for the sterilization. 



With Th. Nogier and Rochaix, 2 I have shown that an exposure of 

 10 minutes (lamp immersed in a basin of water only a few centimeters 

 deep) hardly altered the chemical composition of the water. The 

 organic matter, ammonia, the nitrites, the nitrates, and other sub- 

 stances dissolved, were almost always in the same proportions at 

 the end of 10 minutes; they were not in the least transformed by 

 the passage (several seconds) in an immersion apparatus, a length 

 of passage sufficient for complete sterilization. 



We add that the taste and odor of the water are not altered. 



THE WATER THUS TREATED IS HARMLESS. 



Although the chemical composition of the water is not changed by 

 the ultra-violet rays, the question as to its harmlessness yet remains. 

 Is the water thus sterilized harmless ? 



We have fed daily for a month dogs, rabbits, and guinea pigs with 

 water from a Nogier apparatus. Nothing in their general health, in 

 their weight, or their temperature indicated the least ill effect. 



THE ACTION OF THE ULTRA-VIOLET RADIATION ON THE FLUORESCENT 

 MATTER CONTAINED IN WATER. 



Concerning the processes for controlling the sterilization of water, 

 Dienert 3 has made a very interesting note. There exist in all surface 

 waters fluorescent matter of organic origin. Sterilization by the 

 ultra-violet rays (as well as by ozone or otherwise) causes a notable 

 decrease in the quantity of such matter. Water treated by these rays 

 differs therefore in this respect from the natural river water before its 

 passage through our apparatus. 



1 J. Courmont, Th. Nogier et Rochaix. C R. Ac. des Sciences, 30 mai 1D10. 



2 J. Courmont, Th. Nogier et Rochaix. C R. Ac. des Sciences, 12 juillet 1909. 

 s Dienert. C. R. Ac. des Sciences, 21 fevrier 1909. 



