404 AGE OF THE WORLD. 



without being charged with making any violent deduc- 

 tion, that in the great revolution of our system around 

 the centre of space, we are undergoing gradual changes 

 which are essential to the great scheme of creation, 

 though at present incomprehensible to us ? 



In our consideration of the influence of time on the 

 structure of the earth as we find it, we discovered that, 

 in ages long past, the vegetation of the tropics existed 

 upon these northern parts of the globe ; and geological 

 research has also proved that over the same lands the 

 cold of an arctic winter must have long prevailed the 

 immense glaciers of that period having left the marks of 

 their movements upon the face of the existing rocks.* 

 We know that during 3,000 years no change of tem- 

 perature has taken place in the European climate. 

 The children of Israel found the date and the vine 

 flourishing in Canaan; and they exist there still. 

 Arago has shown that a trifling alteration of tempera- 

 ture would have destroyed one or the other of these 

 fruit-bearing trees, since the vine will not ripen where 

 the mean temperature of the year is higher than 84, or 

 the date flourish where it sinks below that degree. 



How immense, then, the duration of time since these 

 changes must have taken place ! The 432,000 years of 

 Oriental mythology is a period scarcely commensurable 

 with these effects ; yet, to the creature of three-score 

 years, that period appears an eternity. The thirty-three 

 millions of geographical miles which our solar system 



* "As to the polishing and grooving of hard rocks, it has lately 

 been ascertained that glaciers give rise to these effects when 

 pushing forward sand, pebbles, and rocky fragments, and causing- 

 them to grate along the bottom. Nor can there be a.ny doubt that 

 icebergs, when they run aground on the floor of the ocean, imprint 

 similar marks upon it." Principles of Geology, or the modern 

 changes of the Earth and its Inhabitants considered as illustrative 

 of Geology: by Charles LyelL M.A., F.R.S. Travels through the 

 Al/is of Savoy, and other parts of the Pennine Chain, with Obser- 

 vations on the Phenomena of Glaciers : by James D. Forbes, F..U.H .. 



