Introduction. li 



§ 12. State of the Sky. 



69. After April 27. 1842, the quantity of clouds is estimated ; the whole 

 hemisphere covered Avith 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 uj)on 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 flowARD, 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 ^he 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™ 50^ in advance of the Makerstoun 

 time. 



75. In the daily observations 1841, the bifilar magnetometer was observed 

 2\ 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. 



* Early in 1843 I discontinued the use of a stove, and ultimately had it removed. 



