xlviii 



Inteoduction. 



Table 24.- 



-Comparisons of the Makerstoun Standard Barometer with the Duke of Argyle's 

 Standard Barometer. 







Makerstoun 







Standard 



Duke of Argyle's 



Makerstoun 



Tfiiyitcs 



Standard. 



Standard. 



Duke of Argyle's 

 Standard. 



in. 



in. 



in. 



30-046 



30050 



+ 0-004 



29-596 



29-598 



+ 0-002 



29-594 



29-596 



+ 0-002 



29-172 



29-176 



+ 0004 



29-508 



29-512 



+ 0-004 



29-552 



29-556 



+ 0-004 



29-224 



29-228 



+ 0-004 



29-446 



29-450 



+ 0004 



29-562 



29-560 



-0002 



The mean correction of the Makerstoun Standard Barometer to the Duke of 



in. in. 



Argyle's is — 0*003, and, therefore, to the Royal Society's — 0'012. 



From seventeen comparisons, the correction of Adie No. 1 to the Makerstoun 

 standard is — 0*005. 



57. The observations are corrected for temperature by Schumacher's Tables, 

 given in the Report of the Royal Society; those of the mountain barometer are cor- 

 rected by the constant — 0*017, and of the standard, by — 0*012, the reduction to 

 the Royal Society's standard. 



The cistern is 213 feet above the level of the sea. 



§ 9. Theemometees. 



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

 are 0*3 inch in diameter, and a tenth of a degree can be estimated on the scales. 

 They are placed 4 inches apart, on a wooden slab, the bulbs projecting below it. 

 They were placed, from July 1841 till January 22. 1842, in the middle of a wooden 

 case, the sides and tops of which were formed like Venetian blinds. 



The case was quite open below and on the side next the observatory, the 

 thermometers being about 9 inches distant from the middle window, on the north 

 side of the observatory ; and after January 22. 1842, from the west window on the 

 same side.* This change was rendered necessary by the stove being brought to the 

 middle of the observatory. 



* There is no doubt that these thermometers were placed in a bad position, being open to the 

 effect of radiation from the observatory. This was, to some extent, unavoidable, as there was neither 

 recess nor door on the north wall. Early in 1843, I had the thermometers placed on a revolving 

 case, which could be turned by means of cords and pulleys from within the observatory when re- 

 quired, and left afterwards with a good norih exposure. 



