“Apparently no sharp dividing line can be drawn between true Algol stars and those whose variations are continuous. Periods of nine variables in this region, which are of the Algol type or closely resemble it, have been determined and are here discussed.”

Periods of 25 Variable Stars in the Small Magellanic Cloud http://adsabs.harvard.edu/abs/1912HarCi.173....1L (1912)
Context: A remarkable relation between the brightness of these [Cepheid] variables and the length of their periods will be noticed. In H. A. 60, No.4, attention was called to the fact that the brighter variables have the longer periods, but at that time it was felt that the number was too small the drawing of general conclusions. The periods of 8 additional variables which have been determined since that time, however, conform to the same law. The relation is shown graphically in Figure 1... The two resulting curves, one for the maxima and one for the minima, are surprisingly smooth, and of remarkable form. In Figure 2, the abscissas are equal to the logarithms of the periods, and the ordinates to the corresponding magnitudes, as in Figure 1. A straight line can readily be drawn among each of the two series of points corresponding to the maxima and minima, thus showing that there is a simple relation between the brightness of the variables and their periods. The logarithm of the period increases by about 0.48 for each increase of one magnitude in brightness.

"1777 Variables in the Magellanic Clouds" http://books.google.com/books?id=UkdWAAAAYAAJ&pg=PA87 (1908) Annals of the Astronomical Observatory of Harvard College Vol.60. No.4

Source: Disturbing the Peace (1986), Ch. 5

Wanderlust: A History of Walking (2001)

Source: The Causes of Evolution (1932), Ch. IV Natural Selection, pp. 103-104.

Periods of 25 Variable Stars in the Small Magellanic Cloud http://adsabs.harvard.edu/abs/1912HarCi.173....1L (1912)

Augustus (1937)
Context: History does not repeat itself except with variations, and it is idle to look for exact parallels, but we can trace a resemblance between the conditions of his time and those of to-day. Once again the crust of civilization has worn thin, and beneath can be heard the muttering of primeval fires. Once again many accepted principles of government have been overthrown, and the world has become a laboratory where immature and feverish minds experiment with unknown forces. Once again problems cannot be comfortably limited, for science has brought the nations into an uneasy bondage to each other. In the actual business of administration there is no question of today which Augustus had not to face and answer.

Source: Periodic Kingdom (1995), Chapter 1. The Terrain