INDEX TO PART II. 
OP THE 
PHILOSOPHICAL TRANSACTIONS 
FOR THE YEAR 1880 . 
A. 
Abney (W. de W.). The Bakerian Lecture. On the Photographic Method of Mapping the least 
Refrangible End of the Solar Spectrum, 653. 
B. 
Bakerian Lecture (see Abney). 
C. 
Coal-Measures, fossil plants of, 493 (see Williamson). 
D. 
Darwin (G-. H.). On the Secular Changes in the Elements of the Orbit of a Satellite revolving about a 
Tidally distorted Planet, 713 (for contents see p. 713). 
Double refraction in Iceland spar, 421 (see Glazebrook). 
E. 
Electric discharges in vacuum tubes, 561 (see Spottiswoode). 
Ellis (W. E.). On the Relation between the Diurnal Range of Magnetic Declination and Horizontal 
Force, as observed at the Royal Observatory, Greenwich, during the Fears 1841 to 1877, and the 
Period of Solar Spot Frequency, 541, 
MDCCCLXXX. 5 Y 
