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NOTE to the Quarterly Meteorological Observations from Decem- 

 ber 1836 to March 1838, published in the Edinburgh Philoso- 

 phical Journal for October 1837 and July 1838. 



The barometer used in December 1836, was a cistern one by Robinson of 

 London. On all the other occasions a syphon one, on Bunten's construction, 

 made by Adie of Edinburgh, was employed. It was placed in a closet ad- 

 joining a room in which there was a fire. In December 1836 and'Marcli 

 1837, the external thermometer was placed outside a window having a north- 

 ern aspect, and in June and December 1837, and March 1838, on the roof 

 under shelter. In December 1836 and March 1837, the moisture was ascer- 

 tained by Leslie's hygrometer ; for which a moistened bulb thermometer was 

 substituted in the subsequent observations. The place of observation is 

 about 160 feet above the sea. 



The observations for September 1837, were taken at a height about 15 

 feet above the other station. The instruments were the same. The baro- 

 meter was placed at a window having a southern aspect, but removed during 

 the day to one having a northern aspect. The thermometers were suspend- 

 ed in the shade near the barometer. From the indications of the external 

 thermometer, 0^.5 must be substracted from those of the moistened thermo- 

 meter 0°.l. 



The barometer in December 1836, was not corrected for capillarity. With 

 that and other exceptions mentioned, all necessary corrections have been 

 applied. 



At the June observations on the Drachenfels, at which one of the members 

 of the Committee assisted, the barometer used was by Bunten of Paris, and 

 carefully protected from the sun. The thermometers were placed near the 

 barometer. Ths error of the thermometers was ascertained a few days after- 

 wards, when the moistened thermometer stood 0°.2 above, and the other 0"'.2 

 below the freezing point. The variation in the height of the barometer at 

 10 p. M. June 21, was partly occasioned by the instrument having been re- 

 moved and replaced, which seems to have removed some previously existing 

 adhesion. 



Since September 1837, Sir J. Herschel has recommended that the obser- 

 vations should not be prolonged beyond twenty.five hours, as no additional 

 benefit was found to result from the longer period. This suggestion has been 

 complied with in the subsequent observations. 



