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Published online by Cambridge University Press: 16 March 2015
**** I Have the pleasure to send you two papers: the first on the changes, which the moment of a magnetical needle or bar undergoes as a function of the elapsed time, and of the variations of the temperature; the second, in the German language, is an extract of a letter to Professor Kupffer of St Petersburg, exhibiting the changes of the time of 300 horizontal vibrations, in Christiania, of my invariable magnetical cylinder, made by Dollond in 1819, from 1820 to 1839.
page 390 note * The 30th July 1834, Hofrath Gauss observed the same cylinder in the same place in the garden of the Observatory, and found reduced time, T, of 300 vibrations = 759″.29, which gives intensity = 1.7672.
page 390 note † [The value of the horizontal intensity at Edinburgh compared with Paris (.840) was not deduced, as Professor Hansteen supposes, from a single comparison. It was repeated by me in two different years with almost perfect agreement, and confirmed by observations at Brussels, a station independently compared with Paris. Professor Bache of Philadelphia has since found the same relative intensity for Edinburgh agreeing to the 3d decimal place.—J. D. F.]
