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climate. The glacial theory was first mentioned in 1837 ; by 1857 it was 
accepted with avidity all over the world, and nearly everything diluvial was 
attributed to ice ; Agassiz even spoke of glaciers coming down to the sea in 
Brazil : there are signs of them, I believe, in Equatorial Africa. I think I 
was the first to revive the Huttonian doctrine about rain — that is to say, to 
show that there must at one time have been twenty or thirty times as much 
rain as at present. Mr. Pattison has been obliged to limit his quotations 
from Prestwich and Lyell ; but if he had given more, he would have shown 
that they both always demanded ice-action, or floods produced from melting 
snow. Dana imagines that the old Mississippi was fifty miles wide, and was 
supplied by melting snow. He does not give any calculation as to the 
depth of the snow-field, or sun’s heat, to supply a river of that size. I 
calculate it would take 600 times the present rain and heat to supply 
water to feed Dana’s river.* There is no passage in Prestwich which 
gives you the idea that he contemplated a previous greater rainfall than we 
have at present ; in fact, he thought the mean temperature was only just 
above freezing. The prehistoric period was a complete snow age according 
to Prestwich ; with one degree over frost there could be very little rain 
indeed, yet all the torrents which he speaks of, were to be the products of 
melting snow or an occasional torrential shower ; he depended almost entirely 
on snow and ice-water for the excavation of the valleys, which Sir C. Lyell 
referred partly, to tidal action. There has been as much change on this 
point in geology as on most others, arising from more extended observation. 
Lyell at first followed Buckland, and urged strongly, in his early writings, 
that man was extremely modern, and that species were permanent, and not 
subject to change. I mention this to show that a similar great change of 
view has taken place on the permanency of climate : first came the water- 
action of Hutton and Playfair ; then, the view of ice and snow-action of 
Prestwich and Lyell ; and now Mr. Pattison has been so bold as to say that all 
the world are agreed that there was excessive rain-action, or a pluvial period. 
This certainly helps his argument for reconsideration of the question, because 
it shows that those eminent geologists did not always hold the same theory, 
but had their primary, secondary, and tertiary views and notions within 
sixty or seventy years. I fii’st brought forward my theory in 1853, of greater 
rivers ; and when afterwards, in 1866, I suggested my pluvial period, I was 
told that it would not do, as it smacked of the Deluge. To-night Mr. 
Pattison has only taken the geological branch of evidence of the antiquity 
of man. As you are aware, there are many other sources by which you can 
get some confirmation on this subject as a check on your conclusions. Mr. 
Pattison has not alluded to Egypt, where there is a long chronology and a 
list of kings for 30,000 years. The question there is, whether those kings 
* Geol. Mag., Sept. 1875. 
