INTRODUCTION. li 
§ 12. SraTE oF THE Sky. 
69. After April 27. 1842, the quantity of clouds is estimated ; the whole 
hemisphere covered with clouds being 10; and no clouds, 0. 
After the same date, the motions of the clouds were estimated. A marked 
portion of cloud, which passes nearly through the zenith, is watched till the direc- 
tion is found in which it seems to run down one corner of the Observatory. About 
the end of 1843, the points of the compass, referred to each corner of the Observa- 
tory, were marked upon the surrounding paling; before this, the direction was 
estimated very nearly, as the walls of the Observatory are in the meridian and 
prime vertical. 
* 70. The nomenclature adopted is that of Howarp, with a few combinations. 
The term scud refers to that loose, generally amorphous, and often rainy, cloud 
which is the lowest of all excepting the stratus. The state of the sky is generally 
observed after the magnetometers, at each observation hour. 
71. The remarks on the weather, after May 1. 1842, were too lengthy to print 
on the same page with the other meteorological observations ; an abstract has been 
given there, and the original remarks printed in an Appendix. 
§ 13. GENERAL AND RECAPITULATORY REMARKS. 
72. As there was no computing-room apart from the Observatory, a small 
copper stove was placed in the south-east anteroom, in order that the latter might 
be used in the winter months for this purpose. In January 1842, this was removed, 
and a larger copper stove placed in the position S in the plan, from a belief that it 
would keep the temperature within the Observatory more uniform.* 
73. The mean-time clock is by DENT ; it is kept at Gottingen mean time, the 
errors being determined by comparisons with the transit clock in the Astronomical 
Observatory. The rate is always kept very small. 
74. The time used throughout this volume is Gottingen mean solar time, astro- 
nomical reckoning. The Gottingen time is 49™ 50s in advance of the Makerstoun 
time. 
75. In the daily observations 1841, the bifilar magnetometer was observed 
25 minutes after, and the balance magnetometer 2} minutes before, the minute of 
the declination observation. 
76. During the term-day observations 1841, the bifilar and balance magneto- 
meters were observed alternately 2} minutes after the minute of declination obser- 
vation. 
* Warly in 1843 I discontinued the use of a stove, and ultimately had it removed. 
