GEOLOGICAL PROBLEM. 



309 



bility, is mathematically demonstrable, and which has 

 recently had some singular evidence in its favour ad- 

 vanced by geologists. In 1851 I brought forward, at 

 the Geological Society of Dublin, a case of augular frag- 

 ments of granite, occurring in the carboniferous limestone 

 of the county Dublin, and explained the phenomena by 

 the supposition of the transporting power of ice. In 

 1855 Professor Eamsay laid before the Geological Society 

 of London a full and detailed theory of glaciers and ice 

 as agents concerned in the formation of a remarkable 

 breccia, of Permian age, occurring in the central counties 

 of England ; and still more recently the same agent has 

 been employed by the geological surveyors of India to 

 account for the transport of materials at geological 

 periods long antecedent to those in which ice transport is 

 commonly supposed to have commenced. The motion 

 of the earth's axis would reconcile all the facts known, 

 and it must be regarded as a geological desideratum to 

 determine its amount and direction, and to assign the 

 cause of such a movement. The solution of this problem 

 I regard as quite possible." * 



This very interesting question has already been solved 

 by the distinguished French mathematician, M. Leyerrier. 

 At p. 163 of tome ii. of the Annates de I ' Observatoire 

 Imperial de Paris, M. Leverrier gives 4° 5P 42" as the 



SUPERIOR LIMIT OF THE INCLINATION OF THE EARTH 's ORBIT 



upon the ecliptic of 1800, subject, however, to small 

 corrections depending on any possible inaccuracies in the 

 values of the planetary masses employed in his researches. 

 Mr. J. E. Hind, Superintendent of the Nautical Almanac, 

 to whom I am indebted for the subjoined table, states 

 that the amount of correction cannot well exceed 8', and 



* Appendix to a Narrative of the Discovery of the Fate of Sir John 

 Franklin and his Co mpanions, by Captain McClintock, R.N V p. 395. 



x 3 



