Cotswold Hills, with observations on the Aneroid Barometer. 257 
in the “vacuum-vase”’ of the instrument. This however is, I 
believe, a mistake*. 
In its present form, then, I conclude that a correction for 
temperature is needed for the exact measurement of heights. 
There are also two palpable defects, one of which is that the hand 
or index is frequently so far from the face of the dial, that its 
parallax leads to error in reading off the scale, which may easily 
amount to 20 feet in height. This however may be somewhat 
corrected by bending the hand so as to make it nearly touch the 
face of the dial. The other fault is that the inch is subdivided 
into only forty parts, one of which corresponds to 22 feet in 
height. It would be better to have it graduated to hundredths 
—so that the actual reading off should tally at once with the 
barometric tables now in use—or if the size of the dial will not 
admit of this, to subdivide the inch into fifty instead of forty parts, 
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 .......+0++. 198 
Perret PELs conc caleitent owsseenctaneestins 292 
Christ Church tower, Cheltenham (top)... 343 
RIOMESOVV OOM ELUN fe csavcesevanceesirmt sveesins 652 634°2 —17'8 
See caRMR MEISE cd occa hc biedin «hein acre vapin adie vans 715 691°4 —23°6 
Me HCOMUEG PLTML ss. 25 ce tee ete atcctcee cents 725 740:27 +15:27 
Finger-post on top of Frocester Hill ...... ...... 780 
Rtas tanrny lla: <3 250 Shay og uag «tps oie end seen 733 
irs sh sy m0nd Ss Hall .25....c-s0cs-nervens mami sebees 810 
igs acco tains Scet cadena an ence aaciaa 823 825'5 +2°5 
PICK EU cc canscsuetsecstercecsrecearsae 929 935°9 +6°9 
BEV MELUIME TOT idee achat tccwlecoscnctedesvarecs 966 
PRR PERUT GO5h- cca do cmediushads. Seces tessa 969 960°5 —8°5 
Leckhampton Hill ...0....s.0ceseseeees ways 978 969°9 —8'] 
Base of Bredon Hill tower ........seeeseeeee 979 
Cleeve Hill or Cleeve Cloud ............... 1081 1066°8 —14°2 
MPAIV ENTE ont aia nnaeadsehreescadee senses detec: 1396 
With the exception of Standish and Robin’s Wood Hills, the 
* T have since ascertained it to be one. M. Vidi himself informed me in 
November last, that although he at one time made some experiments on 
the use of gas in the “ vacuum ”’—(qy.) “‘ vase,”’—he has now rejected it 
altogether. 
Ann. & Mag. N. Hist. Ser.2. Vol. v. 17 
