202 Professor Haugkton's Geology. 



the text, and made the work all appendix, we have no doubt 

 he would have done greater justice to his acquirements and 

 powers. We have proof of this when we compare the remarks 

 on geological time made in the fourth lecture with the opposite 

 remarks which the appendix affords. 



In the text, Professor "W. Thompson's allowance of time, 

 based upon calculations as to how long the sun may have been 

 shining upon our earth, if certain assumed conditions are cor- 

 rect, is stated to be " very liberal," and geologists are soundly 

 rated for not being contented with one, or even five hundred 

 millions of years; while in the appendix we find Professor 

 Haughton making an elaborate computation according to a 

 formula of Helmholz — who thought to solve the difficulty by 

 inquiring how long it would take for the earth to cool down 

 from an incandescent state to a temperature at which any 

 organic being we are acquainted with could live — and finding 

 that 1280 millions of years would elapse as the time of cooling 

 from 122° to 77°. Commenting on these figures, the Professor 

 says, "Vast as the period of 1280 millions of years must 

 appear to us, yet the globe was habitable, in parts at least, for 

 a longer period, for the polar temperature would have admitted 

 of the existence of animal life before it was possible in Britain, 

 and it is also highly probable that the rate of cooling of the 

 earth was slower than is here assume d." 



If we pass from this part of the subject to the zoology and 

 palaeontology of Mr. Haughton' s manual, we find ourselves un- 

 able to applaud the text, and without the consolation of finding 

 it handsomely contradicted in the appendix. 



In speaking of the Foraminifers, Professor Haughton pro- 

 ceeds as if Carpenter, Jones, and Parker had not commenced 

 their well-known labours, and he accordingly follows a method 

 of division in which the arrangement of the cells, whether 

 rectilinear, spiral, or irregular, is made the basis of classifica- 

 tion. Much information on this subject will be found in the 

 admirable paper from the pen of Dr. Carpenter, which we 

 published in our vol. vii., p. 278 j* and we may cite a passage 

 from the last edition of his work on the microscope, in which 

 he states that, " plan of growth is a character of very subor- 

 dinate importance among the foraminifera, and that any 

 classification which is primarily based upon it must necessarily 

 be altogether unnatural/ 5 



Professor Haughton gives a representation of the Ptcryyotus 

 acuminatum, or as it is now called Slimonia acuminata, and it is 

 a pity that in this case he did not refer to the specimens 

 obtained more than two years ago by the British Museum, from 



* " On the Structure, Affinities, and Geological Tosition of the Eozoon 

 Canadonse." 



