158 Barometric Observations. — On portable Barometers. 



1822. 



Maximum of the year .... 30.55 

 Minimum of the year . . . 29*10 

 Barometrical range of the year . 1 -45 



ON PORTABLE BAROMETERS. 



To the Editors of the Philosophical Magazine and Journal. 



Having for some time paid attention to the mode of deter- 

 mining the heights of piaces by means of the barometer, I beg 

 leave to observe, in reference to a suggestion of Mr. Squire, in 

 page 75 of your last Number, of a defect in the common porta- 

 ble barometers, from the uncertainty of the relative capacities 

 of the tube and cistern, that it is possible that some instru- 

 ment-makers may omit to mark on some part of the instru- 

 ment 



