398 Barometric Observations. 



teor which discharged the stones at Weston in North America, 

 on the 14th of December 1807, was 15,360 toises, or about six- 

 teen miles. • 



BAROMETRIC OBSERVATIONS. 



To Mr. Tilloch. 



Elstree, 14th Nov. 1820. 

 Sir, — I send you the observations made at Leighton with a 

 barometer on the 10th instant. 



Thermometers. 



The above heights are corrected for the size of the tube. 



Not observing any corresponding observations in your last 

 Number, I am almost afraid your readers, who possess barome- 

 ters, are not fully aware of the great importance to the scientific 

 world it is to know the altitude of the different towns and villages 

 in the United Kingdom. Or perhaps they may suppose the 

 course of observations a matter of difficulty. A single trial will 

 convince them of the facility of the task. 



I am this day favoured with the observations made by Colonel 

 Beaufoy at his observatory. Bushy Heath, viz. 



By a comparison of my portable barometer with two excellent 

 instruments of Colonel Beaufoy, I have discovered a slower sub- 

 sidence of the mercury in the closed cisterns than I had been 

 given to expect. I shall therefore avail myself of an early op- 

 portunity of attempting to find the length of time necessary to 

 wait after fining up the instrument before the reading ought to 

 be made. It is right to observe, that this precaution is not ne- 

 cessarv with barometers that have an open basin, and on that ac- 

 count are more to be depended upon for simgle and expeditious 

 observations ; although for portability the mountain barometer, 

 as improved by Sir H. Englefield, is by far the most convenient. 



I am, sir, yours truly, 



B. Be VAN. 



METEORO- 



