384 Bappicker—On the Influence of Magnetism on the Rate of a Chronometer. 
not think that there is any magnetic influence perceptible, and if there be any, it 
is obvious that itis, compared to the effects in Nos. 657 and 615, exceedingly small, 
and practically of no account whatever. So we see that the balance and its spring 
are the chief, and most probably the only, parts of the chronometer through which 
a magnetic influence is imparted to the rate of the time-piece. A conclusion as to 
which of the two has the greatest effect may, perhaps, be drawn from the follow- 
ing observations of No. 600 (with a platinum silver balance) and No. 274 (with a 
gold spiral) :— 
Situations pope oe pee as Nonbenen Dare 
No. 600. No. 274. 
Detached. — 0" 0°36 +0" 1°32 13 
Magnet to VI +0 8-26 +2 51-50 5 
"= nla -0 38-08 -0 6:80 4 
& Ae +0 0-94 +0 12-14 8 
Ml =O 16 +0 20-60* 9 
This Table shows that the influence upon the balance is considerably greater 
than that upon the spring; and it would be very important to continue these 
observations, if possible, with spirals of known magnetic qualities, in order to see 
if the above result is a general one. But these experiments would be rather expen- — 
sive ones, and could not be made without the continual assistance of a practical 
chronometer-maker. 
Finally, Arnold and Dent observed chronometer No. 274 (and perhaps No. 600 
also, though it is not especially stated) in two different positions as to the mag- 
netic meridian after the removal of the bar, and found the following differences 
of rate :— 
Rate. Rate. 
Direction of VI. =. = Number of Days. 
No. 274 No. 600. 
N + 2°90 -- 0847 3 
) + 1°50 -— 0°84 5 
N + 2°78 — 0°50 3 
S) + 1°67 — 0°97 3 
N + 2°93 - 0°70 3 
* The fifth of the original numbers, of which the above is the mean, is given + 12°-9 (February 20), 
which most probably is (and has been assumed to be) a misprint for + 21°-9. 
