Schaw. — On the Last Glacial Epoch. 513 



In the course of one experiment I tried whether there was 

 any difference in the resistance of the gap when a Voss was 

 used or a coil. The results were, — 



(1.) The condenser was charged up to a slightly greater 

 difference of potential by the Eumkhorff than by the Voss for 

 the same length of spark-gap. 



(2.) The resistance of the spark-gap for the Eumkhorff coil 

 discharge was slightly less than in the case of the Voss. 



These are the results of a few preliminary experiments into 

 this little-known subject. I have reserved a more complete 

 investigation for a future occasion. 



Art. LX. — The Last Glacial Epoch: explained by Major- 

 General Drayson's Discovery of the Second Rotation of 

 the Earth. 



By Major-General Schaw, C.B., E.E. 



[Read before the Wellington Pliilosopliical Society, 13th June, 1894.] 



Plate XLV. 



As you have re-elected me as your President for the present 

 year, the duty once more devolves upon me to open the 

 session by an inaugural address, and I have chosen as my 

 subject one which I hope may give rise to some interesting 

 and instructive discussion— namely, that slow movement of 

 the north pole of our earth which has long been known in an 

 imperfect manner, but which has now been reduced to mathe- 

 matical exactness by Major-General Drayson, and discovered 

 by him to be caused by a second rotation with a very long 

 period. The bearing of this discovery upon the date and 

 duration of the last glacial epoch, and the explanation which 

 it affords of that peculiar epoch of the earth's history which 

 immediately preceded man's appearance, are extremely in- 

 teresting, and I propose to bring the whole matter briefly in 

 review before you this evening. 



In speaking of an ice age or a glacial epoch, I do not refer 

 to anything like a cataclysm, but simply to an extension 

 southwards in the Northern Hemisphere and northwards in 

 the Southern Hemisphere of climatic conditions such as now 

 exist within and near the arctic and antarctic circles. And I 

 assume that this extension of refrigeration was not sudden in 

 its beginning or its ending, but was gradual and slow, and 

 that the effects of such refi igeration were different in different 

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