70 Correspondence of Jerome Nickles. 
On the presence of the vapor of water in certain stars—In 
the course of his researches on the spectrum of the vapor of 
water, Janssen thinks he has noticed its presence in seve 
of the stars, among them, Antares, the spectrum of which 
presents very plainly the lines and_bands of the vapor of water, 
These lines are black, very broad, and have the characteristic 
position. Janssen has taken into account the error pro- 
ceeding from the moisture of the air. On the heights of Mt. 
Etna the air was very dry. The stations where he has made 
trials are, Etna, Palermo and Marseilles. Janssen has observed 
evidence of the presence of the vapor of water also in the at- 
mosphere of Mars and Saturn. 
On the ic Rig of the air.—The inhabitants of valleys 
know that one of the surest signs of rain is the clearness of 
outline mg has color of the distant mountains. It indicates 
great dampness in the air, But it may be asked, how does it 
happen that this dampness aids the transmission of light, while 
it hinders that of radiating heat, as Tyndall has shown. This 
question, raised by de Saussure, has again been iheonstieelll 
Rive has cone that not yes does the peenrthen dust 
become transparent on absorbing the watery vapor, but that 
further, the water absorbed renders the dust heavier and makes 
it fall to the ground. De LaRive also admits that if the pres- 
ence of watery vapor renders the air transparent when it con- 
tains dust or organic particles, its presence is no longer neces- 
sary for this end in the absence of dust. This explains why 
the air is very dry; why the air is so clear over plains of snow, 
and why it is sehen the same on the Peak of Teneriffe in oe 
sequence of the east wind. In the warm season, and in 
when organic life has the greatest activity, the air 7 
= charged with this kind of dry vapor, which in calm 
diminishes in so wonderful a manner the visibility of 
distant objects. Of the various kinds of dust, only those which 
are sorae: 4 in water, for example, common salt, according to 
, are always in the air, even in re s remote from the 
These are the kinds of dust Be pao to the 
fertilization of the soil: a chemist, Barral, has even found 
phosphates. 
According to a meteorologist, Marshal Vaillant, sie 
SRR ters re ere the 
