ON THE MAGNETIC INTENSITY OF THE EARTH. 497 
Note by Major Sazine; being an Appendix to his Report on 
the Variations of the Magnetic Intensity observed at dif- 
ferent Points of the Earth's Surface. 
_ Since the report on the Variation of the Magnetic Intensity 
_ of the Earth, which forms the first article in this volume, was 
_ printed, I have become acquainted with a highly valuable 
_ series of observations. of the magnetic intensity made by M. 
_ George Fuss, of the Imperial Academy of Sciences at St. Pe- 
_ tersburg, in 1830, 1831, and 1832, in Eastern Siberia and 
_ China. I exceedingly regret that these most interesting de- 
_ terminations do not occupy their proper place in the general 
table of my report. I must hope, however, that being included 
in the same volume, they may still, to its readers, contribute 
their due share of experimental testimony to the system of 
_ terrestrial magnetism. . 
__ M. Fuss’s observations were made in two journeys ; one from 
- Irkutzk to Pekin, in the latter part of 1830, including a return 
by a slightly different route the following year; the second 
: ey was in 1832 from Irkutzk to the eastern parts of 
_ Siberia, as far as the longitude of 122° E. of Greenwich. The 
intensities were observed by two horizontal needles, each of 
_ which sustained a small, but uniform loss of magnetism during 
the period of its employment. Corrections were very care- 
fully investigated, and have been applied on this account, as 
well as for changes of temperature. The details, both of the 
_ observations and the corrections, are published in the Memoirs 
_ of the Imperial Academy of Sciences of St. Petersburg, Ser. vi. 
vol. iii. The resulting intensities are there expressed in terms 
_ of the arbitrary scale in which Paris = 13482, being connected. 
_ therewith by means of M. Hansteen’s determinations in 1829 
at Irkutzk and Kiatka, where M. Fuss also observed. 
_ I have included in the annexed Table the variation and dip 
_ observed by M. Fuss at all his intensity stations. The dip 
_was taken by an instrument of Gambey’s, until an accident 
_ befel it at Nertschinsk, when the subsequent observations 
_ were made with an inferior instrument. The geographical 
_. positions are those given by M. Fuss. 
__ The ground, traversed by M. Fuss enabled him to observe 
_ the culminating points of the isodynamic lines of 1°5 and 1°6. 
_ These he states to be between the longitudes of 107° and 
VOL. vi. 1837. 2k 
