1915] BOVIE—SCHUMANN RAYS 145 
even if it did, the method would not be practical, because the 
ozone formed would be harmful to the milk and cream. They 
were not able to sterilize water completely by ultra-violet light, 
but they found that the number of bacteria was greatly reduced 
by the treatment. 
BILLON-DAGUERRE (1), nephew of the inventor of the daguerreo- 
type, described in 1909 a new quartz lamp for the sterilization of 
liquids. The source of light was a quartz discharge tube filled 
with rarefied hydrogen gas. Other gases were also used. Such a 
lamp, according to BILLOoN-DAGUERRE, emits Schumann rays. 
In a paper published in 1910 he figured an improved lamp and ~ 
‘asserted that with this lamp water containing 29,000 bacteria 
(Bacillus coli) per cc. could be sterilized at the rate of 5 liters 
per minute. The discharge tube of the improved lamp was 
25 cm. long and 20 mm. in internal diameter. It was excited by 
the current from the secondary of an induction coil which gave 
a spark 15 mm. in length; the primary of the induction coil was 
operated by a current of 2 amperes at 6 volts. He said that the 
lamp was more than 20 times as efficient as the mercury vapor arc. 
Urspam, Scat, and FEIGE (9) questioned the efficiency of 
Schumann rays for sterilizing, because of their small penetrating 
power. They recommended a lamp with terminals of carbon and 
of aluminum for sterilizing large quantities of water. 
LyMAN (7) studied the absorption by water of the Schumann 
rays and showed that light of wave-length 1750 Angstrém units 
was completely absorbed by a layer of water o.5 mm. thick. He 
pointed out the improbability of the results claimed by BILLon- 
DAGUERRE. 
The Schumann rays are undoubtedly very active chemically, 
but they have such a small penetrating power that it seemed 
improbable to Professor LyMAN (at whose suggestion the writer 
undertook this work) that in a sterilizer such as described by 
BILLON-DAGUERRE the bacteria would be exposed to sufficient 
light to kill them. BrtLon-DAGUERRE passed the water, which 
he was attempting to sterilize, through his apparatus at so 
rapid a rate that sufficient exposure for sterilization seems im- 
possible, since the organisms in the water could be affected 
