5C6 A TREATISE 



imposed upon myself the task of observing and re- 

 cording the changes of the Barometer, as far as T was 

 able, every half-hour, day and night, during the pe- 

 riod of one complete lunation. 



The result of this undertaking I have now the ho- 

 nour to lay before the Society ; and if in matter or 

 form it contains any thing worthy of their attention, 

 or of a place amongst their Researches, it will afford 

 me a decree of satisfaction that will more than reward 

 me for my labour. 



I. OF THE PERIODICAL DIURNAL CHANGES 

 OF THE BAROMETER. 



THE DETAIL OF F A C '■ 



V. 



The Detail of Facts is comprehended in the fol- 

 lowing record of observations made on the Barometer, 

 as regularly as 1 was able to perform it, every half- 

 hour, both day and night, during the lunation which 

 intervened between the 31st of March and the 29th 

 of jipr'd 1794. To these I have added the state of 

 the Thermometer and Wind* with the appearance of 

 the sky. 



VI. 



My observations of the Barometer were taken -with 

 scrupulous exactness ; and although the weighty hand 

 of sleep has more than once deprived me ot observa- 

 tions that I was just about to make, and was anxious to 

 record, 1 have never ventured to assume any probable 

 state of the Mercury as an actual observation. 



VII. With 



