28 BAROMETRICAL REGISTER KEPT AT ECCLES MANSE. 



tained several times, but more especially on the 10th February and 

 21st and 22d September. 



The range of the barometer for 1 832 is thus found to be one inch and 

 a half. The lowest boiling point of water was therefore 209.32 Fah- 

 renheit, and the highest 2 12. 17 ; the mean for the whole year 211.08, 

 the range of boiling point being 2.85. 



2. A fall of y$ c was frequently attended with a shower, or even 

 heavy rain. A subsidence of T g ?T was very speedily followed by the 

 same consequences, as on the 14th and 15th August 1832. This result 

 forms a striking contrast with observations made between the tropics, 

 where we find, in similar circumstances, a more decided fall of the mer- 

 cury, seldom less than -J^ previous to the occurrence of rain, which is 

 about double the subsidence as obtained by this register. 



3. When frost occurred, the barometer generally rose from 1 ^ IT to 

 half an inch. Snow most commonly depressed the mercurial column, 

 while a thaw elevated it. 



4. The mean height of the barometer for the two years 1832 and 

 1833 is, after correction for temperature, (29.523 f 29.257) -f- 2 = 

 29.390 ; from which we may calculate the elevation of Eccles above the 

 level of the sea. 



By the formula 45 (6 T), applied to the diminution of temperature 



by the rarefraction of air, reckoning the density of the air in the same 

 latitude at the sea 1, and assuming 29.82 as the standard barometer 

 pressure for Britain, we have 29.82 : 29-39 : : 1 : .985 density of air 

 at Eccles. Then 1 -f- 985 = 1.015. By substitution the formula be- 

 comes 45 (1.015 985) = 45 x 030 = 1.35 = difference of tempera- 

 ture between the two stations. 



Assume the law of equable progression, 1 : 270 : : 1 -35 : 364J = feet 

 above the level of the sea, shewing a gentle ascent of 315 feet to 

 Stitchell, which is about five miles distant, and 680 feet above the sea, 

 according to Mr Blackadder, and 533| to Hume Castle, which, by the 

 same authority, has an elevation of 898 feet. 



We arrive at the mean temperature, by comparing the mean tempera- 

 tures of stations well established. The mean temperature of Glasgow, 

 which is situated in 55 31' 32" north latitude, is 47 75', and that of 

 London 50, St Pauls being situated in 51 30' 49" nortli latitude ; from 

 which it appears that the temperature of the atmosphere diminishes 

 0.53 Fahrenheit, for every additional degree of latitude. Eccles is 

 situated in about 75 40' north latitude, or 11 miles south of Glasgow, 

 with a difference of + 1*3 temperature. Hence we have for Eccles a 

 mean temperature of 47 85'. By deducting the difference of tempera- 

 ture of the two stations, as obtained by the formula, from the standard 

 temperature 48 66' * 1.35 = 47 31' = the mean temperature, which 

 is, however, probably less than the true number by a considerable sum. 



