Barometric Olservations. 



237 



The observations made in different places, on the 1st Monday 

 of the last four months, are not more satisfactory than the above. 

 I find the mean difference between Leighton and Bushy- Heath 

 219,332 feet ; but there remains a great uncertainty on the true 

 difference of level : it amounts to 73,.') 12 feet in February, in 

 calculating the observations at 8 and at 12 o'clock, while in 

 November it is only 3,216 feet from the observations at 9 and 

 at 10. 



Sir, — 1 send you the observations made at Arlington-street 

 on the 12th of this month. The reflections which follow tliem 

 are inserted merely for you, and Mr. Bevan, if you think that 

 they may be interesting to him. 



As I am going abroad at the end of this month, I shall not be 

 able to furnish your Magazine with other meteorological obser- 

 vations made in Camden Town. 



1 am, sir, your most obedient servant. 



To Air. Tillock, A Constant Reader. 



Crunipsall, Lancashire, Mar. 13, 1821. 

 Sir, — I send you observations on the barometer, he. made at 

 this place on Monday the 12th instant. 



I observe that there is a typographical error in my former 

 communication, published in the last Number of your Magazine, 

 which it may be well to correct, as it affects the sense of the 

 passage in which it occurs. The word " connection," in the 

 fifth line from the top of the 154th page, should be read " cor- 

 rection." 



Your obedient servant, 

 To Mr. Tilloch. John Blackwall. 



Leighton. March 24, 1821. 

 Dear Sir, — 1 .'end you the observations made with the baro- 

 meter on the 13th instant, at this place, and also at Bushy-Heath, 

 by Col. Beaufoy. 



I.BIGH- 



