1864.] 



of Ireland and Cornwall, 



143 



In Donegal there exists a Primary Conjugate System, and a Secondary 

 System, making with the Primary an angle of 32° 24'. In the Mourne and 

 Newry Mountains there is a Primary Conjugate System, and two Secondary 

 Systems at each side of the Primary, making angles of 31° 46' and 30° 56'. 

 In Cornwall there is a Primary and also a Secondary Conjugate System, 

 making an angle of 27° 28'. And m Fermanagh there are Primary and 

 Secondary Systems, forming an angle of 31° 1'. 



Having given, in detail, the observations on which the preceding results 

 are founded, the author says Collecting together into one Table the 

 resuks of the precedmg observations, we find the following Table of Primary 

 and Secondary Joints (True Bearings) : — 



Name. 



Waterford.j Donegal. 



Mourne. 1 Cornwall. 



Fermanagh. 





N. of E. 



32° 26' 



N. of E. 



26° 16' 



N. of E. 



39° 40' 



N. of E. 



32° 34' 



N. of E. 



21° 30' 





of N. 



31° 37' 



W. of N. 



29° 35' 



W. of N. 



38° 31' 



W. of N. 



32° 55' 



W. of N. 



25° 48' 





N. of E. 



58° ir 



N. of E. 



58° 40' 



N. of E. 



70° 40' 





N. of E. 



54° 0' 



Conjugate to First Secondary (C) | 



W. of N. 



60° 3' 





W. of N. 



70° 40' 





W. of N. 



55° 20' 





S. of E. 



5° 50' 







N. of E. 



4° 0' 





Conjugate to Second Secondary / 

 (C") I 



E. of N. 



4° 30' 





W. of N. 



7° 35' 



W. of N. 



6° 30' 





The only remarkable agreement as to direction of joints disclosed by the 

 preceding Table is that between Waterford and Cornwall. If we compare 

 together the Primary and Secondary Joints in each locaHty, we find the 

 following Table of Angles between Primary and Secondary Joints : — 





Waterford. 



Donegal. 



Mourne. 



Cornwall. 



Fermanagh. 



Between Primary (A, C) 

 and First Secondary- 



(A',c') ;. 



+27= 5' 



+ 32° 24' 



+31° 46' 





+31° 1' 



Between Primary (A, C) 

 and Second Secon- 

 dary (A", C") 



-37° 11' 





-30° 56' 



-27° 28' 





This Table discloses a very interestmg and unexpected result ; viz. that 

 in Waterford, Donegal, Mourne, and Fermanagh, the angle between the 

 Primary and first Secondary Joint- Systems ranges between the narrow 

 limits of 27° 5' and 32° 24', and that in Waterford, Mourne, and Cornwall, 

 the angle between the Primary and second Secondary Joint- Systems ranges 

 from 27^28' to 37° 11'. 



