7 
H. A. Hazen—The Sun Glows. 209 
between the ordinary sunset glow upon clouds or vapor com- 
paratively near the earth and the later after-glow, whereas we 
should expect a continuous phenomenon if the vapor were 
uniformly distributed in depth. There is no evidence to show 
that the vapor is uniformly distributed; in fact Professor Vettin, 
of Berlin, has shown that the clouds havea tendency to arrange 
themselves in well defined layers at nearly constant heights. 
“Nature” for December 20th, 1883, gives the following table 
from his researches :— ' 
Cloud. Height in feet. 
Lower 1600 
Cumulus. - 3800 
Cloudlets .._. 7200 
Under Cirrus 12800 
(pper Gite 26 se a ae 23000 
The Suggestion is also made that this indicates a geometrical 
progression in the heights, with a ratio of two. such a ratio. 
exists we can see that there might be a long interval between 
the highest and lower strata. 
, +He most serious objection yet advanced however has been, 
that the rain-hand spectroscope shows an entire absence of 
watery vapor. This objection is answered by the results of an 
investigation made by F. W. Cory of England, and recently 
Presented to the London Meteorological Society. He found 
that a rainband as high as 70 per cent was followed by a light 
rain and one as low as 10 per cent was succeeded by a heavy 
Show, also that the spectrum is not affected previous to a snow 
fall except negatively, i.e. the rain-band diminished several 
days beforea snow. He suggests that when vapor is transformed 
into snow crystals it does not cause a rain-band and that there 
48S no donbt that when rain falls, after a low eetghe = 
e 
of rain-band, it is due to either melted snow or hail. 
-Teport comes from Magdeburg that in the spectram of the 
ca 
is ap- 
* 
