US 



Barojnettic Olservations. 



LEIGHTON. 



9 

 10 

 11 

 12 



Barom. 



2!)- 995 

 30-0()0 

 30-()U7 

 30-017 

 30-017 



Wind- 



E.N.E. 



N.E. 



N.E. 



N.E. 



E. 



BUSHY-HEATH. 



9 

 10 

 11 



12 



Barora. 



29-751 

 29-751 

 29-755 

 29-760 

 29-756 



Wind. 



N.E. bv E. moder 

 N.E.byE. do. 

 N.E. by E. fresh. 

 N.E. bv E. do. 

 N.E.bvE. do 



Weather. 



Foggy. 



do. 



do. 

 Cloudy. 

 Hail. 



From some calculations already made, it appears that Colonel 

 Bcaufoy's barometer is about 230 feet above mine, and prol)abIy 

 about 526 above high water in the River Thames at Somerset- 

 House ; but how much thepoint of high water at that place is 

 above low water spring tides at open sea, remains a desideratum 

 •not much to the credit of our great metropolis, and which it is 

 to be hoped will soon be removed. 



I beg leave in this place to correct a note published in page 18 

 of your last Number, by Mr. Gary, relative to the estimated 

 height of his instrument above the mean level of the sea, as that 

 calculation was founded upon a r-cported heigiit of the Royal 

 Society's barometer, which I afterwards found, by levelling, not 

 to be quite correct. 



There is also at present an uncertainty about the melbi level 

 of the sea, depending upon the e.xlremes of high and low water 

 at both spring a.id neap tides. But until some more correct-de- 

 termination of '.he relative hciglit of the range of the tides at sea, 

 to some fixed spot m London, is made, it will not be prudent to 

 assume a quantity that may t?oon require correction ; instead, 

 therefore, of 7 1 "25 feet above tlie mean level of the sea, I would 

 have it read 56*72 feet above high water in the Thames near So- 

 merset-House. 



From the very valuable instruments used in the Trigonome- 

 trical Survey of Great Britain, 1 was induced to expect some ac- 

 .curate determinations of the heights of the principal stations se- 

 lected on that survey. I have had opportunities of trying the 

 relative height of five of these stations, and am sorry to find a 

 variation amongst them of more than 50 feet. B. Bevan. 



i 



