23b 



Barofhetric Observations. 



the several places of observations, and what is perhaps of more 

 importance, towards ascertaining, more exactly than is yet known, 

 what are the causes which locally affect the atmospheric pres- 

 sure? and under what circumstances may a uniformity of its ac- 

 tion, as exhibited by the Barometer, be reasonably expected ? 



\ beg, in conclusion, to entreat of those gentlemen who keep 

 meteorological journals, to imitate the example of Mr. Gary, in 

 p. 160 of your last number, by communicating exact observa- 

 tions, made by their Barometers, on the days and hours above 

 specified : these more minute observations, for comparison with 

 the monthly and other means from their tables, cannot fail of 

 proving highly useful. J. Farey, Sen, 



P. S — I am glad that Mr, Bevan has called the attention of 

 your readers to the general inaccuracy of the Ordnance Trigono- 

 metrical Heights: the fact is, that paltry and insufficient instru- 

 ments have been depended on /or Elevations', used with less 

 care, as to simultaneous and often repeated observations, than 

 would have been proper, with other and far more efficient instru- 

 ments : in p. 429 of your 4Sth volume, and on other occasions, I 

 have before adverted to these circumstances. 



BAROMETRICAL OBSERVATIONS. 



26, Arlington-street, Camden Town, 12th March 1821. 



The difference of levels between Leighton and this place for 

 S o'clock, bv Laplace's formula with the coefficient 18393™ or 

 10057,6 fathoms, is .. .. feet 39,668 Diff. 



By the method of Hutton . . 89,412 + 0,144 



For 1 2 o'clock, by Laplace's .. 109,656 



By Hutton's 109,536 0,120 



The mean of the levels by Laplace's 99,462 

 The difference between the observation 



at 8 and at 12 is .. .. 20,388 



By Hutton's, is .. .. 20,124 



The mean by Hutton's ., ., 99,474 



Difference 



0,264 0,012 



The 



