PIONEERING DIFFICULTIES. 



27 



II.] 



"En resume, quandje soutenais devant 1'Academie que les elements 

 de Lavoisier devaient etre considered, ainsi qu'il avait e*tabli lui-meme, 

 non comme les elements absolus de 1'univers, mais comme les elements 

 rehtifs de 1'experience humaine ; quand je professais, il y a longtemps, 



FIG. 21. Different rates of motion registered by different iron lines. 



que lliydrogbie etait plus pres des me'taux que de toute autre classe de 

 corps ; j'emettais des opinions que les decouvertes actuelles viennent 

 confirmer et que je n'ai point a modifier aujourd'hui."* 



One of the replies to my working hypothesis was that the various 

 chemical elements probably existed in different proportions in the 

 different stars, and that it so happened that in Vega and Sirius one of 

 them, hydrogen, existed practically alone. 



In 1878 I went further, and showed that thousands of solar pheno- 

 mena which had been carefully recorded during the previous years 

 could only be explained by assuming that the changes in the various 

 intensities of lines in the line spectrum itself indicated successive dis- 

 sociations. I pictured the effect of furnaces of different temperatures, 

 and I wrote as follows :f 



* Chemistry of the Sun, p. 205. 



f Proc. Soy. Soc., vol. xxviii, p. 169. 



See also Chemistry of the Sun, chap. 



atvin. 



