Meteorological Observations made at Pekin. ISl 



Letter from M. George Fuss to his Brother at St. Petersburg. 



« Pekin, April 22, 1831. 



« In spite of the numerous obstacles which presented thera- 

 selves during my journey from Kiankso to Pekin,— both from 

 the difficulties of the road, and from a distrust of our Chmese 

 escort,— I have been able to determine at seventeen points, the 

 inclination and the magnetic intensities ; and at eight points the 

 declination and the latitude. The longitudes have not been 

 determined by the precise methods which were particularly re- 

 commended in my instructions (the transits of the moon and 

 the occultation of stars) ; for the erection of the transit instru- 

 ment and the great telescope would have excited too much 

 the attention of the Chinese, and awakened their distrust. I 

 hope, however, that in returning I shall be less embarrassed, 

 and that I may then be able to occupy myself more success- 

 fully with the exact determination of the geographical position 

 of some important points. At Dyan-dsia-keou, (Khalgan,) 

 however, I have observed for the longitude the occultation of a 

 small star in Capricorn, of the seventh magnitude, by the moon. 



" Soon after our arrival at Pekin, there was constructed, at 

 my request, in the garden of the Mission, a column of masonry 

 for astronomical observations, A tent, of a particular construc- 

 tion and very commodious, sheltered the observer from the 

 wind and the weather. The only inconvenience of this loca- 

 lity is, that the horizon is covered almost all round by adja- 

 cent houses. The cross of the Church of the Mission, which 

 is distant from my little observatory only about ten toises, 

 serves as a mark for the declination needle. 



" Though this distance is not very great, I have however 

 obtained a very satisfactory agreement among my observa- 

 tions, after having cut small cavities for receiving the screws 

 of the needle in the plate of marble which covers the column, 

 and upon which the instrument is placed. The dechnation 

 needle of M. Gambey gave me, on the 10th of January, 1831, 

 at Pekin at 3" p.m., a declination of 1° 42' 57^' W. The dip- 

 ping-needle of Gambey gave, on the 30th of December, 1830, 

 a dip of 54° 52'-l, which is a mean between the results ob- 

 tained by two different needles. The method of arbitrary 

 azimuths* gave me, on the 6th of April, 54° 50'-7. It is proper 

 to remark here, that the Chinese do not employ iron in the 

 construction of their houses. I have also observed the horary 

 variations of declination during the winter solstice, and during 



• An account of this method will be found in my Memoir on the Dip 

 at St. Petersburg, inserted in Poggendorfs Annals, Observation 1. - yote 

 hti M. Kuvffcr. 



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