202 Mr. Nixon on the Hills of Dent, fyc.in Yorkshire. 



the distance of the station to the hill. The last column con- 

 tains the heights deduced from the observations at Whaw Fell. 



At the Bear's Head the apparent elevation of Dod Fell, 

 measured by the 4-inch theodolite, was 43' 18", whence the 

 altitude of the former would be 2021 feet. At Ten End the 

 Bear's Head was elevated 40' 9 7 , giving 191 1 feet for the height 

 of Ten End. The heights of Ryssell and Snays Fell are as 

 yet unconfirmed. 



When the mean error of a number of Heights determined 

 from any particular station is considerable, it would appear to 

 argue that the altitude of the station had been assumed in ex- 

 cess or defect according to the sign and by the amount of the 

 error. But if the mean distance of the several hills to the 

 station should greatly exceed the mean of their distances to 

 the other stations, the error, as in the case of Pen-y-gent, may 

 with greater probability be attributed to a false estimate of the 



refraction. Had we made use of —q minus a smaller quantity 



than 18", the discrepancies would have disappeared. 



On 



