and for measuring Heights in the Atmosphere. <2~7 



indications of the barometer, it maybe presumed, as is 

 sometimes known to happen, that a particular spot is af- 

 fected by local circumstances. 



After a long continued series of wet weather, wc may, 

 when the weather becomes fine, expect an uninterrupted 

 continuance of dry weather. 



• If, after a long series of wet weather, the barometer rise 

 above changeable, and the wind veer steady to the north 

 or east points, a continued duration of fair weather may 

 be expected. 



Slow and progressive variations in the barometer, with a 

 fixed and steady state of the wind, indicate permanency with 

 the chancre. 



The barometer standing at or above fair, denotes ge- 

 nerally fair weather, although the atmosphere wear at the 

 time an unfavourable aspect. 



Lastly, The greater coincidence there is of the circum- 

 stances enumerated in the rules above mentioned, the 

 stronger may our confidence be in the expectation of fair 

 weather, and in the continuance of it when present, by the 

 barometer whilst high, remaining stationary, or varying but 

 little, and the state of the atmosphere, and direction of the 

 wind, disposed to be settled. 



In this variable climate, there is no reliance, T think, to 

 be placed on any rules, beyond those above mentioned, for 

 indicating the weather for any length of time together, or 

 for any distant period. 



Many of these rules, perhaps, may appear trite, and as 

 if collected from the observations of others; but, uncon- 

 scious of retaining those of any other person in my mind> 

 I give these as the result of my own experience. 



A Summary Method for ascertaining without the Use of 

 Logarithms, the various Degrees of Elevation in the At- 

 mosphere, by means of the Barometer, which, by the Ex- 

 am pies that follow, will be found to give a tolerably close 

 Approximation to the geometrical Measurement. 



The following Tables are applied thus: 

 1st. Note down the height of the barometer at the lower 

 station, in inches, tenths, and hundredths* ; and the tem- 

 perature of the air, as indicated by the thermometer, 



2dly. In a similar manner note down the height of the 

 barometer at the tippet station; and the temperature of the 

 air (if this differ from the former observation). 



3dly. Subtract the quantity shown by the barometer in the 

 upper station, from that which is shown in the loner station. 



* I have judged it unnecessary to descend below himdredths on the barometer. 



S 3 4thlv. Seek 



