104 Generating Economic Cycles 



sailed the theory that the Moon might be responsible 

 for certain terrestrial tides: "To say . . . that the 

 motion of the Earth meeting with the motion of the 

 Lunar Orb, the concurrence of them occasioneth the 

 Ebbing and Flowing, is absolute vanity . . . because it 

 is not exprest, nor seen how it should so happen. . . ." ^ 

 The object of the present chapter is to show how 

 Venus may produce the cyclical effect. We shall 

 approach the explanation by considering certain im- 

 portant recent discoveries in Solar Physics. 



Recent Theories of the Sun 



Solar Physics may be said to have had its beginning 

 in 1610 when Gahleo's discovery of sunspots intro- 

 duced the idea of variability in the Sun. It became a 

 science with clear-cut aims in consequence of the per- 

 tinacity of a German amateur, Herr Heinrich Schwabe 

 of Dessau. Schwabe's discovery of the sunspot cycle 

 not only has a direct bearing upon the theory of the 

 Sun's activity, to which reference will be made later 

 on, but falling as it does within the realm of the most 

 exact of the sciences, its history cannot fail to give 

 courage to economists engaged in the study of perio- 

 dicities in notoriously inexact data. 



Schwabe began his work in 1826. His observatory 

 was a small apartment at the top of his dwelling and 

 his instruments were two small telescopes with low 

 powers. His method of observation is described^ 



^ Galileo: The Systeme of the WorW. in Four Dialogues Translation 

 by Thomas Salisbury, pp. 421-422. 



2 "Address delivered by the President, M. J. Johnson, Esq., on pre- 

 senting the Medal of the Society to M. Schwabe." Monthly Notices of 

 the Royal Astronomical Society, vol. xvii, pp. 126-132. 



