28 BeppicKker—On the Influence of Magnetism on the Rate of a Chronometer. 
Finally, a chronometer, H, was observed on an irregular octagonal magnetic 
disc, in the same positions as F and G, and directly opposite results were arrived 
at. And further on it was seen that when the chronometer was moved only + of 
an inch towards the north pole, a very sensible change of rates was invariably 
observed. The rates observed in these two positions were :— 
Dainty Rate. 
Situation of Chronometer H. 
Second Position, _ 
First Position. AeA) Taaihee woah. 
XII pointing N. + 5%1 + 6°7 
XII 35 E. +20'4 ~ + 22°6 
XII 5 8. + 3:0 + 3°5 (and + 4*1) 
XII 7 W. + 16°9 + 23°7 
We sce from this that the displacement of the chronometer towards the north 
accelerated all the rates; and that the most considerable changes took place in 
the E. and W. positions, where the radius passing through the balance centre 
was at right angles to the magnetic axis; the least considerable changes in the 
N. and 8. positions, where the balance centre was lying in the magnetic axis. 
The above experiments are open to the same objections I had to make against 
the majority of the former ones. There is no account of the temperature, nor of 
the compensation of the time-pieces; the detached rates have not been taken in 
different positions, so that we do not know anything about eventual fixed mag- 
netism in the chronometers. And then it is to be regretted that Harvey brought 
chiefly the main-spring into regular positions as to the magnet, and the more so 
as his third conclusion from the observations of A seems to show that it.is the 
balance which is acted upon by the magnet.* Any conclusive evidence as to 
which part is particularly influenced, however, Harvey’s experiments do not 
afford. His observations with the magnetic dise are very interesting, and perhaps 
worth a repetition, when modified as suggested before, but it appears doubtful 
whether they will lead to any result of general value at present, where the whole 
question of magnetic influence on chronometers is still so far from being finally 
solved. 
* Horner’s objection (No. 15), that Harvey’s experiments did not admit of any deduction, since 
‘“‘the balance was affected by two magnetisms, changeable in position and proximity, viz., the direct 
one of the magnet, and the induced one of the main-spring,” would of course apply to all magnetic 
experiments. But as we do not want to obtain anything but the result of all these combined mag- 
netisms for practical application, Horner’s objection ceases to have any weight. 
