1931-2.] Dr A. W. Roberts on Algol Variation. 
73 
will take under the mutual attraction of their component 
masses. 
In the case of two southern Algol variables of this class — 
V. Puppis, Ch. 2852, 
R.R. Centauri, Ch. 5099, 
observations made with the new prismatic equatorial, generously 
given me by Sir John Usher, indicate that the amount of distortion 
at the junction of the two stars is apparent and measurable; that, 
indeed, the form of the dual system conforms to that obtained by 
Prof. Darwin in his classical research on “ Figures of Equilibrium 
of Rotating Masses of Fluid ” (plate 22, Philosophical Transactions 
of the Royal Society , vol. 178). 
These are only two of the many allied lines of research 
intimately connected with the consideration of Algol variation. 
Indeed, this whole direction of thought and inquiry brings us to 
the very threshold of the question of stellar evolution, and to the 
heart of not a few of the greatest cosmical problems. 
When the certain future development in spectroscopy brings 
within the apprehension of this method of research movement in 
the line of sight of stars as faint as the tenth or twelfth 
magnitude, and when the bounds of the science of stellar variation 
will be extended to include changes of only one-tenth of a 
magnitude in extent, the data at the disposal of astronomers for 
the determination of conditions under which binary systems are 
formed will be both extensive in amount and sufficient in 
character. 
We may exemplify some of the general conclusions already 
stated by a more particular consideration of the Algol variable 
recently discovered at the Royal Observatory, Cape Town. 
Unfortunately, observations were only begun at Lovedale when 
the star was well down in the west in the evening, and thus an 
extended series of observations on any evening was not possible. 
The most, however, was made of the time available. 
