[ 95 ] 



On a NEW KIND of PORTABLE BAROMETER 

 /or MEASURING HEIGHTS. By the Rev. 

 JAMES ARCHIBALD HAMILTON, D.D, 

 M. R. I. A. 



X HE acknowledged conveniency and accuracy of 4)arometrical ReadDec.3, 

 menfuratioas have induced thofe who combine with a tafte for 

 experimental philofophy, mathematical Ikill and a talent for 

 calculation, to aim at facilitating this work, by rendering the pro- 

 cefs for determining the adual diiferences of altitudes within all 

 poffible limits, from barometrical obfervations made at different 

 flations, fimple and expeditious. 



This they have efFeded by a few general and obvious precepts 

 and tables conilruded on the bafis of a theory deduced from adual 

 obfervation, and confirmed or amended by accurate and repeated 

 trials ; thefe helps, added to the variety of improvements made on 

 the conflrudion of the portable barometer, and the excellent 



method 



