Barometiic Observations. 



75 



the second Monday in the ensuing months, before the results 

 are published. I may however say that a steady uniformity in 

 the results must not be expected, under different circumstances 

 of distance, and direction and strength of wind ; and there may 

 be some laws at present unknown that influence the height 

 of the mercury. It is hoped that a few difficulties or anomalies 

 in the onset may not induce us to abandon the pursuit. Before 

 any regular list of the height of towns, rivers, hills, &c. can be 

 published, it is highly desirable to settle the point of zero; and 

 as a change of signs + and — will be troublesome to the general 

 reader, and as the surface of the sea at low water, spring tide, 

 has been used for such a standard, it may be right to adopt it 

 as sufficient to express every part of dry land in the country. 

 Considering London as the most important part of these king- 

 doms, it will be desirable to ascertain the correct height of some 

 iew public and accessible points in the metropolis above this 

 zero. 



Perhaps the best way to obtain this object would be to pro- 

 cure a correct section of the river Thames from London to 

 Sheerness. At present I am not aware of any such section, al- 

 though it is a river of more consequence than any other in 

 Great Britain. 



If any of your readers should know of any such section, 

 either of the whole or part of the river, a reference to it will be 

 very acceptable. I am, dear sir, yours truly, 



B. Bevan. 



Blackwater, Hants, Jan. 11, 1821. 

 To Mr. Tllloch. 

 Sir, — In compliance with the wish of Mr. Bevan, I send you 

 the state of the barometer and thermometer on the Sth instant 

 at this place. 1 unavoidably lost the observations at S and D 

 o'clock, but suppose it of no material consequence. At a rough 

 estimation, the cistern of the barometer may be about 2G0 feet 

 above the level of the sea. I cannot be certain to a few feet. 

 I am, sir, your obedient humble servant, 



Geo. D. Bins. 



Barom. 



29-0.9 

 29-08 

 29-07 



29-0.1 



Wind. 



K2 



I 10- 



E. gloomy. 



Cirrhi, cirrostrati 



Hi cirroeumuli. 

 Gloom v. 



