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DESCRIPTION of a new portable BAROMETER, 

 by the Rev. ARTHUR M'GUIRE. Communicated b 

 the Rev. H. U S S H E R, D. D. M. R. J. A. and F. R. S. 



X HE art of meafuring abfolute and relative accefllblc heights Read May 

 by the barometer has, within a few years, been brought to a very ' ' 

 confiderable degree of perfedion, by ingenious theory, criticjil 

 experiments, and improved inftruments. 



This mode of meafurement is, in pradlice, of Angular llm- 

 plicity, and the labour of calculation, originally not very great, 

 is almoft annihilated by the induftry of the ingenious. 



As all accuracy in thefe meafures depends upon the inftru- 

 ment, every attempt to difcover any fource of error, even 

 without its remedy, may be of ufe, by exciting ingenious 

 artifts to exert their induftry in rendering this valuable inftru- 

 ment more unexceptionable. 



F It 



