270 



Mr. J. N. Lockyer. 



[June 19, 



10' 15 (mercury yellow) bright. 



Heating continued ; pump stopped clicking. 



Time 11.37. — ISTa melted ; spark refuses to pass ; glass instantly 

 covered with white deposit where the sodium boiled. 

 Spark now passes, showing stratification. 



Spectrum of retort consisted of pure hydrogen without a trace of D ; 

 all traces of hydrocarbon also gone. Hydrogen line Gr seen very bright. 

 Pump clicking. 



Na again heated, not boiled ; pump stopped clicking. 



Yellow glow in retort showed D very broad, C without F. 



Time 11.50. — Pump nearly clicking; stratifications in retort; spark 

 bright red in capillary, pure hydrogen with blue line remarkably 

 brilliant; D visible two inches above pole in retort; yellowish film 

 forming at top of retort five inches from sodium ; retort otherwise 

 clean ; pump not clicking, much hydrogen being carried over. 



Structure spectrum in retort getting much brighter ; discoloration 

 at top removed by Bunsen, but forms a beautiful green film below ; 

 glass just above Na clean ; trace of D three inches from pole. 



Time 11.55. — Still pure hydrogen in capillary. 



Metal slowly distilling and film forming above it ; very bright 

 yellow glow at pole in retort, gives no trace of the green line ; much 

 hydrogen coming over. 



Time 12.0. — Pump now clicking ; only hydrogen visible in capil- 

 lary ; yellow glow now seen over metal. Glass cleared by Bunsen 

 has been discoloured by platinum pole ; on heating deposit, D seen 

 very bright, C scarcely visible, and very faint trace of green line ; D 

 visible for three inches above pole, gradually passing away into hydrogen 

 structure ; pump carrying over much hydrogen, which is brilliant in 

 capillary. 



Pump beginning to click, metal more strongly heated ; clicking 

 stopped; new system of stratifications in retort, glowing with a blue 

 light as far as mercury joint ; violet above mercury joint. On further 

 heating, the old conditions are restored. In the retort, D now bright 

 •one inch above pole ; C very dim ; no green line. 



]STa boiled ; spark refuses to pass ; spirit lamp raised one inch ; spark 

 again blue in tube ; its spectrum consists of hydrogen structure 

 without F or C. Tube again cleared by Bunsen flame; Na boiling; 

 yellow glow blending with violet one inch from pole ; fine stratifica- 

 tions in higher part of retort ; pump carrying over much hydrogen. 



Pump clicking ; Hg line at 11"0 visible ; violet Hg line very faint. 



Tube again cleared by Bunsen flame ; yellow line two inches from 

 pole ; green line very faint ; no trace of C ; pump carrying over 

 hydrogen ; violet light now visible over metal. 



Time 12.20. — Tube again cleared with Bunsen ; olive-green now 

 becoming apparent at pole ; green line well seen ; tube now keeps 



