Schaw. — On the Last Glacial Epoch. 533 



geological epochs with those in the Northern Hemisphere, 

 at least for some distance backwards from the date of the 

 ice age. I need not perhaps refer to other objections raised 

 on the grounds of discoveries in Egypt which are considered 

 to indicate a high civilization there at a very remote date, 

 because the ice age had little or no influence on Egypt or any 

 tropical or subtropical couutries. As far as the facts of the 

 ice age are concerned, man may have lived for millions of 

 years in those regions of the globe while north and south the 

 climate would have been very unfavourable for human occupa- 

 tion. 



It is, undoubtedly, very remarkable that none of the great 

 astronomers of the past should have discovered, and that few 

 of those of the present day should yet have admitted the truth 

 of, the second rotation of the earth ; but this is not the first 

 time in the world's history that such a thing has happened. 

 New truths are slowly accepted, especially when they are 

 opposed to received theories which have the sanction of great 

 names ; but magna est Veritas et prcevalebit. If General 

 Drayson's discovery be a truth, as I conceive he has proved it 

 to be, it must be accepted in course of time. 



Appendix B. 



Since this address was written and delivered, I have had 

 the advantage of reading " General Astronomy," by Professor 

 Young, of New Jersey College, in which he explains very 

 clearly the precession of the equinoxes on the principle of the 

 gyroscope. 



He shows (pp. 134, 135) that the attractions of the sun and 

 moon on the parts of the equatorial protuberance of the earth 

 which are nearer to them produce a "couple" which is 

 equivalent to a pull on the poles of the axis of daily rotation, 

 tending to bring the plane of the earth's equator into coin- 

 cidence with the plane of the ecliptic, and that this pull, like 

 that of a weight attached to one end of the axis of a gyro- 

 scope, results in the same effect — viz., a slow secondary rota- 

 tion of the earth in the opposite direction to the diurnal 

 rotation. He assumes, however, according to the received 

 theory, that this second rotation is about the axis of the 

 plane of the ecliptic. General Drayson has shown that, as a 

 matter of fact, the second rotation is about a different axis, 

 and he suggests that the cause is the preponderance of the 

 Northern Hemisphere over the Southern, due to the vastly 

 greater extent of land in the former. 



On reconsidering the question in the light of Professor 

 Young's demonstration, I see that the equatorial protuberance 

 is largely, if not mainly, the cause of a precession of the 



