42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 79 



distant about i mile. There are no serious irregularities of 

 surface in the vicinity excepting the two river valleys of 

 the Don and Dee. To the north, at a distance of about i km. 

 the Don flows eastwards to the sea ; the Dee flows into the 

 sea at a distance of about 3 km. to the south-east of the 

 College. Between the college and the sea is a golf course 

 covered for the most part with grass. Westwards is the 

 High Street of the Old Town and beyond this there is an- 

 other street. Further west, grass pasture extends for about 

 one kilometer. Southward are open spaces beyond which the 

 modern town is reached. The enclosure in which the Steven- 

 son screen, the Beckley and check rain gages and the grass 

 minimum thermometer are exposed, lies to the north-east of 

 the Observatory at a distance of about 50 m. The " North- 

 wall " screen in which the recording thermometers are ex- 

 posed is erected on the wail outside the north window of the 

 uppermost story of the observatory. The nature of the soil 

 and sub-soil is loam and sand. 

 Pressure. 



The monthly and annual means of pressure are the means of the 

 values published in the Daily Weather Report and refer to 

 the telegraphic station at Aberdeen. The telegraphic station 

 was in the town of Aberdeen from 1860 until 188S when 

 the telegraphic work was transferred to the Observatory. 

 The telegraphic readings were made at 8^ to June 1908, 

 then at 7'\ Corrections have been applied to the earlier 

 figures to reduce them to 7^\ The present height of the 

 barometer above mean sea level is 26.8 m. All means refer 

 to 7'' and have been reduced to 32° F., Mean Sea Level and 

 corrected for gravity by reduction to Lat. 45°. 

 Temperature. 



The monthly and annual means of dry bulb temperature are the 

 values published in the Quarterly Weather Report 1871- 

 1880 (inclusive) and in Hourly Readings 1881-1920. They 

 are derived from hourly tabulations of the records of the 

 ]:)hotographic thermograph which is situated in a north-wall 

 screen on the uppermost story of the Observatory. The 

 height of the thermometer bulb above the ground is 12.5 m. 

 Rainfall. 



The rainfall totals are taken from the following sources: 



1871-1880 Temiinal Hour 24''. Hourly Tabulations 



(manuscrijit). 

 1881-1920 Terminal Hour 24''. Hourly Readings. 



