[ 31S ] 



BAROMETRIC OBSERVATIONS. 



Leighton, 17 Oct. 1820. 

 Dear Sir, — I send you the observations made at this place with 

 a barometer on the principle of Sir H. Englefield's (No. 391), 

 with the hope of inducing others of your correspondents to do 

 the same, for the purpose of making out a table of the altitudes of 

 different parts of the country. They are as follow : 



The height of the mercury in the basin of my barometer I con- 

 sider (until corrected) to be 311 f feet above the level of the sea : 

 those persons who have made simultaneous observations will be 

 able to calculate the height of their stations : and by a few repeti- 

 tions of similar observations on the 10th of November and on 

 the 11th of December next, an additional number of altitudes 

 may be found. I beg leave to say, that when I sent you the 

 general invitation to persons in possession of a good barometer, 

 to make a course of hourly observations from 8 a.m. to 12, on 

 the 10th day of each month, for the remainder of this year, (vide 

 last No. p. 234,) 1 was not aware, until the paper was sent off, 

 that the 10th of December would fall on a Sunday. I have 

 therefore proposed Monday the 1 1th in its place; and if it should 

 be thought worth the trouble of continuing the same kind of ob- 

 servations in the ensuing year, it may not be amiss to agree upon 

 the second Monday in each month, for the day of making them, 

 always observing the barometer at the commencement of each 

 hour, from 8 to 12 inclusive. 



By comparing the observations made at the same minute in 

 different parts of the country for a few months, it may bring to 

 light some new properties of the atmosphere not in general un- 

 derstood ; it will afford some satisfactory information of the ex- 

 tent to which the equal pressure mav in future be relied upon 

 for distant barometrical measurements. 



It will always be desirable to state the estimated or measured 

 height of the barometer in relation to some fixed natural point 

 in the neighbourhood, such as the surface of a meadow near a 

 river, or the summit of some well defined hill, &c. 



I anj, dear sir, yours truly, 



B. Bevan. 



METEORO- 



