534 The Rev. S. Haughton on Physical Geology. [Dec. 20, 



solution either floating in the air and waiting to enter the flask as soon 

 as it was uncovered, or lying concealed in the oils, ether, and other bodies 

 which I regarded as nuclei. The varied behaviour of oils under different 

 conditions, as pointed out in my second memoir*, has not been attended 

 to ; and because in many experiments in the hands of others oils have 

 been inactive, it has been denied that oils have any action at all on 

 these solutions. I confess that I was not able to reconcile the results 

 as stated by my opponents with my own results, until within the last 

 few months, when I set to work to repeat Professor Grenfell's experi- 

 ments, during which it became plain to me, what I had not before 

 suspected, that the hygrometric condition of the air has a powerful in- 

 fluence on these solutions ; so that under one set of conditions bodies may 

 act as nuclei, while under another set they may be inactive, as in the case 

 already cited, where sodic acetate solution by exposure during damp 

 weather becomes inert even to a crystal of the salt itself. But the exact 

 determination of these conditions can only be settled by a further long 

 and laborious experimental investigation upon which I am now engaged. 



II. "Notes on Physical Geology. — No. III. On a new Method of 

 finding Limits to the Duration of certain Geological Periods/'' 

 By the Rev. Samuel Haughton, M.D. Dubl v D.C.L. Oxon., 

 P. B.S., Professor of Geology in the University of Dublin. 

 Received October 4, 1877. 



In the preceding Note I have proved that the elevation of Asia and 

 Europe displaced the axis of maximum inertia through 69 miles t, in the 

 direction of the meridian of the Andes, away from Greenwich. The 

 axis of rotation being thus separated from the axis of figure by 69 miles, 

 or 1°, commenced to revolve uniformly on a right cone round the axis of 

 figure, and would continue to do so for ever, if not prevented by friction. 



Astronomers are agreed that the motion of the pole at present is 

 secular and very slow, all traces of wabbling caused by the elevation of 

 Asia and Europe having disappeared. 



The object of the present note is to discuss the motion of the axis of 

 rotation, from the period of the elevation of the continent until (by reason 

 of friction) the axis of rotation came again to coincide with the axis of 

 figure ; and, if possible, to calculate the absolute length of time that has 

 elapsed from the epoch of elevation. 



* Phil. Trans. 1871, pp. 53, 55, 66. See also Proc. Roy. Soc. 1873, p. 210. 



t It is stated, in error, as 207 miles in Note II. {supra, p. 57). All the numerical dis- 

 placements are printed three times their proper values, because, through inadvertence, in 

 integrating equation (8), Note I. page 53, I forgot to divide the numerical coefficient 

 by 3. This error affects all the subsequent coefficients. 



