Declinometek. 



The vane fartliest to the right in the elevation, Plate I., belongs to the anemo- 

 meter ; the others give the direction of the wind. 



System of Obseevation, and Staff of Obseevers. 



5. In the beginning of 1843, the number of daily observations was increased to 

 nine, at two-hourly intervals, commencing with 18'' Gottingen mean time [5^ 10" a.m. 

 Makerstoun mean time) ; these, together with all the other daily observations, were 

 made by Mr Welsh and myself. In the end of 1843, 1 recommended to Sir Thomas 

 Brisbane to add Mr Alexandee Hogg, who had been previously employed in the 

 term-day observations, to the establishment, for the purpose of obtaining a complete 

 diurnal series of observations. Sir Thomas, with his usual anxiety to render the 

 Observatory in every respect useful to science, at once complied with my recom- 

 mendation ; and, in the beginning of the year 1844, hourly observations were com- 

 menced, which were continued till the end of the year 1845. In 1846, the num- 

 ber of daily observations was diminished to nine at two-hovirly intervals, as in 1843 ; 

 three additional observations of the magnetical instruments were made daily, namely, 

 at 23'% 1% and 7^ Gottingen mean time. The other observations in the magnetical 

 observatory, consisted of term-day observations once a-month (discontinued in 

 1846) ; extra magnetical observations during magnetic disturbances ; observations 

 of magnetic dip ; observations of absolute horizontal intensity ; and extra observa- 

 tions of various meteorological phenomena. All the observations have been made 

 by Mr John Welsh, Mr Alexandee Hogg, and myself ; Mr Dods assisting in 

 the term-day observations, and on a few occasions during disturbances. The more 

 difficult observations for the magnetic dip, absolute horizontal intensity, and the 

 determinations of constants were made by Mr Welsh and myself. 



I beg again to express here how much I am indebted to Sir Thomas Beisbane, 

 in every matter connected with the conduct of the Observatory. Without his will- 

 ing co-operation, unceasing kindness, and the confidence which he has placed in my 

 labours from the commencement, it would have been irksome for so small a staff to 

 have performed conscientiously so large a mass of work. Science is not only in- 

 debted to Sir Thomas Brisbane for the foundation and support of the Observatory, 

 but also for the manner in which his expenditure has been made fruitful. 



I owe my best thanks to my principal assistant Mr John Welsh, for the care 

 and assiduity with which he has assisted me on all occasions, whether connected 

 with the making or reducing of the observations. Mr Hogg also has been of much 

 use, especially in observing, and in many matters of handicraft, which his previous 

 experience and inventive skill have rendered available to the purposes of the Obser- 

 vatory. 



Every care was taken by the observers to examine the observations made by 

 those immediately preceding them ; in this way it is believed that few errors have 

 escaped detection. Accidental errors in the times of observation have always been 



