Beppicker— On the Influence of Magnetism on the Rate of a Chronometer. 3 
are the observations by Lieutenant Mudge, given in two Tables, containing land and 
sea rates of chronometers on board H. M. 8. ‘ Leven” (No. 2) on two consecutive 
voyages to the Cape de Verd Islands in 1819 and 1820-21. Of the four chrono- 
meters whose rates are given in the first Table, three lose upon their land rates by 
2°78, 4°16, and 5°:33, respectively, and one gains by 38°77. These differences are 
unmistakable, and only in the case of the second chronometer does it appear pro- | 
bable that a tendency to accelerate may be the reason of the observed change. 
The three other instruments do not admit of any such explanation; they show that 
the change of rate occurred rather suddenly, and that the new rates were kept very 
well, with only slight alterations. [Misprint in the difference of the second chrono- 
meter, which should be 4°:16 instead of 3°:22.] The second Table shows a difference 
of land and sea rates with some certainty only in the four first lines (where all the 
four chronometers lose upon their land rates), but the values are less defined than 
during the first voyage, and generally the chronometers do not show at all as 
equal and steady rates as they did before. As a third and extraordinary instance, 
I give the changes of rate as communicated by George Fisher (No. 5), which 
took place in the nine chronometers on board the ‘‘ Dorothea” and ‘ Trent,” 
commanded by Captain Buchan, during their voyage to the North Pole in 1818. 
All these chronometers gained rapidly on their rates, determined in London 
previous to the ship’s sailing, and, when landed on an island, the acceleration 
ceased immediately in some of them, and more gradually, but not less distinctly, 
in the remaining ones. One chronometer, by Baird, for instance, lost 3°-4 daily 
when on board; upon its removal on shore, its rate was (from August 16th to 
26th) 18°°2, losing, and, again removed on board, it lost daily 6°5. Another 
instrument (Pennington) gained rapidly on board, and began to lose immediately 
1*8 daily when on shore—nearly the same rate it had in London. The following 
short Table shows the more gradual changes as observed in some of the other 
chronometers immediately when landed, August 9th, 1818 :— 
Date. No. 1. Earnshaw. No. 2. Arnold. No. 4. Barraud. No. 5. Arnold. 
Aug. 9 — = = pas 
ree tall + 12°:0 = 09-2 + 81 — 83°5 
re le +10 °2 0 +7°9 — 34 :°2 
ale + 7:98 — 1°85 +0°8 — 86-2 
» 20 + 6:2 -5:1 + 7:1 - 40:9 
oy + 5°63 -5 2 +2°8 - 37°7 
4, 26 + 4:02 - 6:14 +4°3 ~ 41°5 
