524 Transactions. — Miscellaneous. 



during summer 62-7 per cent, and in winter 373 per cent, of 

 the total heat given to that hemisphere by the sun in the 

 year. Calculating by the same method, I find that when the 

 obliquity is 35° the proportions are 66"5 (or two-thirds) in 

 summer, and 33'5 (or one-third) in winter. Such an inequality 

 would produce an exceedingly severe climate. 



The period of a complete second rotation of the earth 

 being approximately 32,000 years, and the date of the maxi- 

 mum obliquity of the earth's axis of daily rotation to the plane 

 of the ecliptic being approximately 14,000 years B.C., the 

 termination of abnormal climatic conditions occurred about 

 5,600 B.C., or nearly 7,500 years ago, and those conditions had 

 endured about 16,000 years. These numbers agree with those 

 separately and on totally distinct grounds assigned by geo- 

 logists to the duration and termination of the last glacial age. 

 It is to be noted also that General Drayson's calculations were 

 published very many years before geologists had arrived at any 

 distinct and comparatively unanimous opinions on the subject. 

 Astronomically, also, General Drayson's discovery, in his 

 mathematical deductions from it, agrees .absolutely with the 

 observations of astronomers in the past two thousand years as 

 to the obliquity of the ecliptic, the precession of the equinoxes, 

 and the positions then occupied by all the principal stars, and 

 this is the best possible proof of the truth of his discovery and 

 the soundness of his reasoning. 



The steps which led to General Drayson's discovery of the 

 second rotation of the earth — with all its far-reaching con- 

 sequences — were somewhat as follow : First, he was puzzled 

 and dissatisfied by the vague and contradictory statements 

 made in all books on astronomy relative to a conical move- 

 ment of the earth's axis without fixing the point about which 

 it turned or the centre of the circle it described, about the 

 precession of the equinoxes, and the variations in the obliquity 

 of the ecliptic. He saw that it was geometrically impossible 

 that the pole of the heavens, or the axis of the earth's daily 

 rotation produced to the heavens, should be describing a circle 

 round the pole of the ecliptic as a centre if this latter pole 

 was movable, as was stated ; for, if the ecliptic or plane of path 

 of the earth round the sun was variable, the pole of this orbit 

 must be moving also. Besides, it was not stated whether the 

 north pole only was moving, or if the south pole was moving 

 also, which was a very important consideration. Then it 

 occurred to him, Why should the plane in which the earth's 

 orbit lies be movable? Is it not much more probable that the 

 inclination of the earth's axis of daily rotation moves ? And 

 the fact that the inclinations of the axes of rotation of the 

 other planets vary from being nearly perpendicular to the 

 plane of the orbit, as in the case of Jupiter, to being nearly 



