Stir John Lubbock’s Address. 283 
but before that there was a period, beginning 800,000 years 
ago, when the eccentricity of the orbit varied from ‘26 to ‘57. 
The result of this would be greatly to increase the effect due 
to the obliquity of the orbit; at certain periods the climate 
would be much warmer than at present, while at others the 
like a date for the last glacial epoch, and we see that it was 
not simply a period of cold, but rather one of extremes, each 
beat of the pendulum of temperature lasting for no less than 
21,000 years. This explains the fact that, as Morlot showed in 
1854, the glacial deposits of Switzerland, and, as we now know, 
those of Scotland, are not a single uniform layer, but a succes- 
sion of strata, indicating very different conditions. I agree 
also with Croll and Geikie in thinking that these considera- 
tions explain the apparent anomaly of the coéxistence in the 
same gravels of arctic and tropical animals; the former hav- 
ing lived in the cold, while the latter flourished in the hot, 
periods. 
_ It is, I think, now well established that man inhabited 
Kurope during the milder periods of the glacial epoch. Some 
high authorities, indeed, consider that we have evidence of his 
made. If time permitted, I should have been glad to have 
surface, has thrown much light; while even in the most culti- 
vated nations we find survivals, curious fancies, and lingering 
ideas; the fossil remains, as it were, of former customs and 
religions embedded in our modern civilization, like the relies 
of extinct animals in the crust of the earth. 
In geology the formation of our Association coincided with 
the appearance of Lyell’s “Principles of Geology,” the first 
volume of which was published in 1830 and the second in 1832. 
At that time the received opinion was that the phenomena of 
Geology could only be explained by violent periodical convul- 
sions, and a high intensity of terrestrial energy culminating In. 
repeated catastrophes. Hutton and Playfair had indeed main- 
