NATURE 



253 



Jan. 14, 1886] 



nature of which may thus suffice to throw hght upon the of Jupiter Hnes are seen which indicate the existence of 



constitution of the planet's atmosphere. an absorbing atmosphere. Cne band appears to corre- 



Working in this manner, Dr. Muggins has observed no spend in spectral position with dark lines due to our 



trace of an atmosphere in the moon, but in the spectrum | earth's atmosphere ; but another band is different trom 



>. — (iXSpectrum of En 



t ; (2) Spectrum of Winnecke's comet ; (3) Spectrum of carbon in olefiant gas ; {\) Specti 

 oil (Huggins). 



any line caused by our atmosphere, and indicates most 1 aqueous vapour probably exists in the atmospheres of 



probably the existence of some unknown constituent. Jupiter and Saturn. 



Saturn has likewise a band common to the earth, so that | The spectrum of Mars indicates in like manner the 



iiclarSpectruz 

 Line F 



existence in the|atmosphere of that planet of matter 

 similar to that which occurs in the earth's atmosphere. 



The absorption spectra of the far distant planets have 

 likewise been examined. 



Padre Secchi and M. Janssen agree with the conclusion 

 that the vapour of water probably exists in certain 

 planetary atmospheres. 



In the absorption spectrum of our atmosphere Professor 



Fig. 24. — First, the s 



cd. Ueluw, th.. liright line: 



, nitrogen, bari 



Piazzi-Smyth'' has noticed a band which appears to be 

 associated with the presence or possibility of rain, and 

 which he has termed the rain-band. Strangely enough 

 in the bright spectrum of the aurora borealis, which comes 



from our atmosphere, there is a line which we cannot 

 identify with the spectrum of any known terrestrial 

 substance. 



Dr. Huggins has likewise studied the spectra given by 



