692 Chronicles of Science. [Oct., 



gaseous nebulse, which by the loss of heat or the influence of other 

 forces have become crowded with portions of matter in a more con- 

 densed and opaque condition. 



6. If the observations of Lord Eosse, Professor Bond, and others 

 are accepted in favour of the partial resolution of the annular nebula 

 in Lyra, and the great nebula in Orion into discrete bright points, 

 these nebulaa must be regarded not as simple masses of gas, but as 

 systems formed by the aggregation of gaseous masses. Is it possible 

 that the permanence of general form of these nebulae may be main- 

 tained by the motions of these separate masses ? 



7. The opinion of the enormous distance of the nebulae from our 

 system, since it has been founded upon the supposed extent of remote- 

 ness at which stars of considerable brightness would cease to be 

 separately visible in our telescopes, has no longer any foundation on 

 which to rest in reference at least to those of the nebulae which give 

 a spectrum of bright lines. It may be that some of these are not 

 more distant from us than the brighter stars. 



8. As far as the speaker's observations extended, they appeared to 

 be in favour of the opinion that these nebulae are gaseous systems 

 possessing a structure and a purpose in relation to the universe 

 altogether distinct from the great cosmical masses to which the sun 

 and the fixed stars belong. "What is this special purpose? Many 

 fascinating theories present themselves in connection with the great 

 problems of the conservation of the energy of the universe, and of the 

 source and maintenance of solar and stellar heat. In the opinion of 

 the speaker, science will be more advanced by the slow and laborious 

 accumulation of facts than by the easier feat of throwing off brilliant 

 speculations. 



A paper on the spectrum of nitrogen was sent by Mr. "Waltenhofen 

 to a recent meeting of the French Academy, in which he states that in 

 an atmosphere of nitrogen properly rarefied the violet rays disappear 

 before the blue and green. The author's observations lead him to 

 believe that nitrogen is a compound body. 



Professor J. Muller has examined the wave length of the blue 

 indium line, by the method and by means of the grating which the 

 author described some time ago. He finds it to be 0*000455 millim. 



When the light of an indium flame is decomposed by the prism it 

 shows two blue hues, one of which, very intense, is situated close to 

 the blue strontium line, but a little further towards the violet end of 

 the spectrum; the other line is still more refrangible, but so much 

 fainter that it cannot be perceived at all in the spectrum produced by 

 means of a grating. 



A valuable application of the spectroscope to toxicological pur- 

 poses has been made by Hoppe-Seyler, who has described it before 

 the French Academy. He applies it to the recognition of poisoning 

 by carbonic oxide. The method is founded on the following observ- 

 ation : — Blood treated with carbonic oxide alone shows the same 

 spectrum as blood containing oxygen, and, if sulphide of ammonium 



