26 Beppicker—On the Influence of Magnetism on the Rate of a Chronometer. 
CHRONOMETER B. CuRonoMeTeR (©. 
Situation. North Pole. 
South Pole. || North Pole. | South Pole. 
il, 2. 
Fig. 1 +100 | 411°7 | 49%5 - 492 | 4 862 
ae + 3:1 + 3:4 -4:2 + 22-4 +18°6 
re cet + 5:0 + 7:0 + 8:7 —- 8:2 - 6°6 
ae Seal) hee NP Sas 415-7 | 412-0 
The chronometers B and C had been taken out of their boxes during these ex- 
periments. The magnet lay horizontally, with its north end directed towards north. 
From the north pole experiments with A and B, figs. 1 to 4, Harvey concludes : 
‘‘An increase of rate resulted from the direct transmission of the magnetic influ- 
ence through the centre of the main-spring; and a diminution thereof when the 
same power passed through nearly the middle of the balance and its spring.” And 
his deductions from a comparison of the two columns given in the first Table (chro- 
nometer A, figs. 1 to 4 and 5 to 8) are: Firstly, the position of the main-spring 
relative to the magnet has a very material effect upon the rate of the chronometer. 
Secondly, the removal of the centre of the main-spring from the magnetic axis by 
equal arcs seems to produce proportional changes of rate. Thus the rates 68°-9 
(fig. 1), and 43°-4 (fig. 3) are very nearly proportional to 50°:8 (fig. 5), and 33°:7 
(fig. 7). A foot-note says that this coincidence may be only accidental. But ‘ it 
would seem as if the translation of the chronometer from the positions occupied in 
fig. 1, through a given arc, occasions a declension in the rate proportional to that 
which takes place when it is moved from the position denoted by fig. 3, through an 
equal are in a contrary direction.” Thirdly, Harvey considers the differences in the 
changes of rate from figs. 1 to 2, and figs. 5 to 6, as well as from figs. 8 to 4, and 
figs. 7 to 8, very surprising; so much the more as the positions figs. 5 to 8 differ 
by 27° only from the situations figs. 1 to 4, respectively. 
As I shall have to reproduce a longer discussion of these observations, which 
Harvey published somewhat later in the year (No. 13), I will reserve till then the 
remarks I have to make about the above experiments and deductions. 
The observations of B and C show directly opposite results, the explanation of 
which ‘‘ apparent anomalies” form the subject of a-special Paper by Harvey 
(No. 12), which will be discussed presently (p. 30). A marked difference between 
north and south pole is perhaps perceptible in chronometer B only. 
In order to compare the effect of the poles and of the equator of a magnetic 
disc of 8 ins. in diameter and + in. in thickness, Harvey proceeded to expose 
three chronometers, B, D, and E, to the influence of the disc in the way repre- 
