DECLINOMETER. xe 
XI 
The vane farthest to the right in the elevation, Plate I., belongs to the anemo- 
meter ; the others give the direction of the wind. 
SysTEM OF OBSERVATION, AND STAFF OF OBSERVERS. 
5. In the beginning of 1843, the number of daily observations was icreased 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, I recommended to Sir THomas 
BRISBANE to add Mr ALEXANDER Hoce, 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 Tuomas, 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-hourly intervals, as in 1843 ; 
three additional observations of the magnetical instruments were made daily, namely, 
at 23, 14, 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 Jonny WetsH, Mr ALEXANDER Hoce, and myself; Mr Dons 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 BrisBaNne, 
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 Jon 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 Hoee 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 
