The Thcrmo-chcmistry of the Alloys of Copper and Zinc. 9 



sphere, but among these there does not seem to be any relation 

 between the atomic weights and the elevations to which the gases 

 ascend in the chromosphere. 



The only non-metals found are H, He, C, and possibly Si. 



Of the 225 lines measured in the ultra-violet region of the spectrum 

 only 29 remain unidentified. 



The Hydrogen Spectrum. — -Twenty-eight hydrogen lines are shown 

 in spectrum No. 3. The wave-lengths obtained are compared in 

 Table III with the theoretical values derived from Balmer's formula. 

 With the exception of HS, which seems to be unaccountably displaced 

 towards the red, the wave-lengths of the ultra-violet lines are found to 

 agree closely with the formula. A slight deviation occurs in the most 

 refrangible lines, the positions of which seem to be distinctly more 

 refrangible than those assigned by theory. 



The continuous spectrum given by the prominences in the ultra- 

 violet, beginning at the end of the hydrogen series, seems analogous to 

 a feature noticed by Sir William Huggins in the absorption spectra of 

 1st type stars, and is possibly due to hydrogen. 



Hydrogen and Helium in the Lower Chromosphere. — From the character 

 of some of the helium lines it is inferred that this element is probably 

 absent from the lowest strata, whilst parhelium appears to be separated 

 from helium, and to exist at a lower level. 



Unlike helium, hydrogen gives very intense lines in the flash layer. 

 These lines are well defined and narrow, even in the very lowest strata. 



Reasons are given to show that the absence of hydrogen absorption in 

 the ultra-violet, and of helium absorption in the visible spectrum, may 

 be due to insufficient quantity of these elements above the photosphere, 

 not to equality of temperature between the radiating gas and photo- 

 spheric background. 



The Corona Spectrum, — The wave-length of the green line deduced 

 from measures of No. 3 and No. 7 spectra confirms the value obtained 

 by Sir Norman Lockyer at the same eclipse. The only other lines 

 shown on these photographs are at A 3388 and near H. 



" The Thermo -chemistry of the Alloys of Copper and Zinc." By 

 T. J. Bakek, B.Sc, King Edward's School, Birmingham. 

 Communicated by Professor Poynting, F.R.S. Received 

 December 4, 1900.— Read January 17, 1901. 



(Abstract.) 



The heats of formation of a number of alloys of copper and zinc,, 

 containing those metals in very diverse proportions, have been 

 ascertained. 



