1879.] 



Note on the Spectrum of Hydrogen. 



31 



6. May we consider the existence of these molecular states as 

 forming a true basis for Dalton's law of multiple proportions ? If so, 

 then the metals in different chemical combinations will exist in 

 different molecular groupings, and we shall be able by spectrum ob- 

 servations to determine the particular heat-level to which the mole- 

 cular complexity of the solid metal, induced by chemical affinity, cor- 

 responds. 



Examples. — None of the lines of magnesium special to the flame 

 spectrum are visible in the spectrum of the chloride either when a 

 name or a spark is employed. The facts recorded in my papers, 

 printed in the " Phil. Trans." some years ago, on the spectra of salts 

 and mixtures, seem all explained in this way. 



I think then that the method of mapping, to be complete, should 

 not only show the metallic lines as produced at various temperatures 

 compared with the Fraunhofer ones, but that for each metal investiga- 

 tions should be made and recorded for as many heat-levels as possible, 

 and for various chemical groupings such as 



CrO Fe 3 Cl 6 

 Cr0 3 FeC 1 3 

 CroOo Fe 



<>; ' 



to give examples, with a view of investigating the facts, to see whether 

 we can trace a molecular evolution in each case. 



Further, the "basic " lines recorded by Thalen will require special 

 study with a view to determine whether their existence in different 

 spectra can be explained or not on the supposition that they represent 

 the vibrations of forms, which, at a early stage of the planet's history, 

 entered into combination with other forms, differing in proximate 

 origin, to produce different " elements." 



V. "Note on the Spectrum of Hydrogen." By J. NORMAN 

 Lockyer, F.R.S. Received December 17, 1879. 



Some years ago, in an account of a research undertaken by Dr. 

 Frankland and myself, it was pointed out that in the tubes we then 

 employed the h line of hydrogen was only seen when the coil and 

 Leyden jar were so arranged as to produce those effects which are 

 generally supposed to be due to high temperatures. The remark, as 

 we distinctly stated, was only made in connexion with the tubes we 

 then employed, which were of widish bore ; it is necessary to mention 

 this because in Germany the remark has been taken to apply to all 

 tubes. 



