« <.,' 



1864.] NATlTItAL HISTORY SOCIETT. 219^* 



chiopods. Professor How has given us Analyses of Mineral Waters 

 in Nova Scotia. Mr. Jones has sent us an interesting paper on the 

 geological importance of Ocean Currents. I have myself occupied 

 some space in our proceedings with my researches on Reptiles and 

 Plants of the Coal-Period; and in connection with these, I would 

 desire to say here that I regard the conclusions of Dr. Hunt in 

 his short but valuable paper on the Climate of the Palaeozoic 

 period as of great importance. Whatever views we may adopt 

 as to the original heated condition of the earth, if we take into 

 account the enormous length of time required by the calculations 

 of physicists * for the reduction of the earth's temperature even 

 one degree, it seems chimerical to suppose that any appreciable 

 effect on climate could have been produced by internal heat 

 in the coal-period. Yet the character and distribution of the 

 flora of that period would appear to imply a comparatively 

 high and equable temperature in the northern temperate and sub- 

 arctic zones. Now if the experiments of Tyndall, cited by Dr. 

 Hunt, can be taken to establish that a small percentage of carbonic 

 acid and an additional amount of aqueous vapour diffused through 

 the atmosphere would largely economise the solar heat by prevent- 

 ing radiation, and thus give conditions similar to those of a glass- 

 roofed conservatory, we have in this consideration, in connection 

 with the known distribution of land and water in the carbonifer- 

 ous era, a sufficient cause for any difference of climatal conditions 

 required by the flora To appreciate more fully the value of this 

 suggestion, it would be necessary to make experiments as to the 

 amount of carbonic acid which might be beneficially present in 

 the air, in the case of plants like those of the coal-period, for 

 instance Ferns, LycopodiacecE and Cycadacoe, and also to calcu- 

 late the effect of such proportion of carbonic acid in impeding 

 radiation. 



Before leaving the work of the Society in the past year, I must 

 not omit to mention that we have not neglected zoology and botany; 

 and among contributions of this kind I could have wished to 

 notice at some length those of Mr. Packard on the Marine Inver- 

 tebrates of Labrador, and of Professor Lawson on Canadian 

 Botany. 



* For example, those of Poisson and Hopkins, which would give 

 100,000,000,000 of years for a diminution of one to three degrees of 

 temperature. 



