Baeojietee. 



1y 



Table 11. Comparisons of the Makerstoun Standard Barometer with the 



Barometer Tkoughton " B," July 8"— 10*, 1847. 



From these comparisons we find 



TeouCtHTON B minus Royal Society's flint-glass, 

 Makerstoun standard minus Troughton B, . . 



: - 0-0417 

 : + 00512 



Makerstoun standard minus Royal Society's flint-glass, . . =+ 0-0095 



In the comparisons made in 1841, the mean of both the crown and flint glass 

 tubes has been employed : making use of Tables 23 and 24, Introduction, 1841-2, 

 we find 



Duke of Aegyle's barometer 7ninus Royal Society's flint-glass, . 

 Makerstoun standard barometer mimos Duke of Aegyle's, . . 



Makerstoun standard barometer minus Royal Society's flint-glass. 



= + 0-0055 

 = + 00029 



= 4- 00084 



The comparisons in 1841 and 1847, therefore, differ only one-thousandth of an 



inch. 



88. All the observations of the Makerstoun standard barometer are corrected 

 by-0-012inch to the mean of the Royal Society's flint and crown glass barometers ; 

 they are also corrected for temperature to 32° Fahr., by Schumachbe's Tables, given 

 in the Report of the Committee of Physics of the Royal Society of London. The 

 cistern of the bai-ometer is 213 feet above the mean level of the sea at Berwick-upon- 

 Tweed. 



Theemometees. 



89. The dry and wet bulb thermometers a a are by Adie and Son. The bulbs 

 6 6 are 0-3 inch in diameter, and tenths of a degree can be estimated with accuracy 

 on the scales a a; the thermometers are attached to a wooden slab c, fixed to the 



