40 Mr. W. 11. Ilyctt un the Heights of some of the 



so that each division should be *02 of an inch. At present, in 

 order to use the tables, it is necessary in reading off to change 

 the vulgar fractions into decimals, which, in jotting down, fre- 

 quently leads to troublesome mistakes. 



It is full time however to come to the table which I promised 

 of the 



Approximate altitudes above the mean level of the Sea supplied 

 by Capt. Yolland, R.E. 



By Ordnance By Aneroid Difference 

 Survey. Barometer, by Aneroid. 

 feet. feet. feet. 



Tewkesbury Church, surface of ground ... 47 

 Gloucester Cathedral, surface of ground ... 56 



Barrow Hill, surface of ground 1 98 



Corse Hill 292 



Christ Church tower, Cheltenham (top)... 343 



Robin's Wood Hill 652 6342 -178 



Standish Hill 715 6914 -236 



Stinchcombe Hill 725 74027 +1527 



Finger-post on top of Frocester Hill 780 



Oxenton Hill 733 



Firs at Symond's Hall 810 



UleyHill 823 8255 +25 



Painswick Hill 929 935*9 + 6*9 



May Hill 966 



BirdlipHill 969 960-5 -8*5 



Leckhampton Hill 978 969-9 -8*1 



Base of Bredon Hill tower 979 



Cleeve Hill or Cleeve Cloud 1081 1066*8 -14*2 



Malvern 1396 



With the exception of Standish and Robin's Wood Hills, the 

 height of each of which is the result of a single observation with 

 the aneroid, the agreement of its indications with those of the Ord- 

 nance determinations is very remarkable, considering the errors 

 to which the present construction of that instrument render it 

 liable. I must observe, however, that they are brought nearer to 

 the trigonometrical measurements by my having rejected some 

 of my first attempts, in which I am almost certain that I made 

 mistakes, and by subsequently adopting the mean of two or three 

 observations, a process which always reduces the extremes of 

 error. Thus for Painswick Hill I had three observations — 



One giving it . . .919 feet. 



Another 934*8 „ 



The third .... 954 „ 

 giving a mean result of 935*9 feet, which differs only 6*9 feet 

 from Capt. Yolland's figures. 



I am sorry that I have not had time to try more of our heights ; 

 but I thought it better to repeat the observations on the same hills 

 in order to obtain mean results, and thus to sift my own probable 

 errors, than to persevere in them undetected. 



