468 Barometric Observations. 
Before a proper comparison can be made between the various 
results obtainable from the observations made by your corre- 
spondents, it should be known what peculiar kind of barometér 
has been used at each place; because all the portable instru- 
ments known by the name of Sir H. Englefield’s barometers re- 
quire a correction for the tube, in consequence of having no re- 
gulating float in the basin. The key to this correction is generally 
marked wish a diamond on the tube in the shape of a fraction, 
indicating the proportion between the areas of the tube and 
cistern. Asswming that the heights of the mercury published i in 
your Magazine have already been corrected for the size of the 
tube, the following results have been calculated by my son. 
Arundel below Leighton. Camden Town above Leighton. 
1821. April .. .. 266 feet.1821. February .. 71 
JUNG ee J <5 Ge Mareh.. .. 284 
July .. .. 248 — 
August.. .. 269 Mean .. 177 
September .. 200 
October .. 209 Crumpsall above Leighton. 
Mean .. 200 Jae’ scieos2eir a 
July A Vos vee bee 
Blackwater below Leighton. August... .. 178 
1821. January .. .. 79 September .. 157 
October oo Vee 
Bristol below Leighton. a yes 
1821. February .. 72 feet. Mean .. 135 ‘ 
tear’ = bee ee Bushey Heath above Leighton, 
June“ da GO 1821. January BAR op 
July~... .+),30 February .. 223 
Mean .. 68 March... .. 190 
Api) ce, ne see 
Epping below Leighton. ree se) SP We 
February .. 110 Ghee her. 98] 
Maren’ | 80) eptember .. | 
+ eae October .. 211 
BP iG! lea tie 
June - 140 November .. 209 
December .. 188 
July .. +. 108 Mean ., 219 
— 
Mean .. 1038 
Lynn 
