Mr Galbraith's Tabka Jbr Barometric Measure^ivefU. 4i3 



Ea'umple. — The height of the mercury of a barometer, with 

 an adjustable cistern of a different bore from the tube, or with 

 the usual cast-iron cistern corrected for capacity, and of 0.25 

 inch in diameter, was observed to be 29564 inches, and the 

 temperature 76° Fahrenheit, what is the height when reduced 

 to the freezing point, or 32° Fahrenheit, when the expansion 

 oi' the mercury only is applied, and when allowance for the brass 

 scale, whose standard is 62° Fahrenheit, also is applied ? 



Height 

 29.564 



Height. 

 29.504 



I. Capillarity to 0.25 iiicbes, +.041 +.041 



II. Exp. for mercury only to TG° — 130 Exp. for mercury an4 brass, — 125 



True height, 



= 29.475 True height. 



29.440 



I am, Sir, your most obedient servant, 



William Galbraith. 

 To Professor Jameson. 



TABLE /. — Capillarity^ or Depression of Mercury in Glass 

 Tubes, to be added to the observed Height of the Mercury in 

 the Barometer. 



