2o8 DESCRIPTION, ISc. 



If three inches be added to the length of the cyUnder, it may be 

 made to delineate the variations of the barometer as well as the 

 thermometer, and thereby to form a complete chart or view of 

 the progrefs of both of them. And if inftruments of this kind 

 were kept in different parts of the country, and their charts 

 compared together, it would afford much information with re- 

 gard to meteorology. 



XI. 



