Bappicker—On the Influence of Magnetism on the Rate of a Chronometer. t 
to base the above law upon these facts, especially as they did not show anything 
but a very natural effect of temperature, for the chronometers shipped at Toulon 
have to pass lower latitudes and higher temperatures, hence retardation; and, 
returning, they come into lower temperatures, hence acceleration. Point (1) finds 
its explanation in the nearly equal temperatures at the Toulon and Paris Observa- 
tories ; and Lesquen’s last remark was an evident proof for Mouchez’s explanation, 
since the acceleration with a decrease of temperature was the larger, the more a 
chronometer retarded with an increase of temperature. Ansart-Deusy, on the 
other hand, thinks Mouchez’s explanation “s'il n’est pas entitrement faux, est au 
moins trop exclusif et trop absolu,” and finds Lesquen’s facts completely explained 
by the action of the ship’s magnetism. Now, it is certainly true that Lesquen’s 
law has very little foundation, for there is, generally speaking, an equal chance for 
a chronometer to lose or to gain when at rest; only in new instruments the accele- 
~ ration will often prevail, as already remarked. It is the same with the translation, 
&c., of a chronometer. It is altogether impossible to give such a law perfectly 
regardless as to all the possible different powers acting on the instruments. For 
instance, temperature would, in most cases, perfectly obscure the changes of rate, 
if they existed as the law expresses; and magnetic action may just as well 
have a considerable effect. But there are other influences still, such as the 
thickening of the oil, which will act, generally speaking, retarding. Each chrono- 
meter is to be considered as a special individual, in its particular way subject to all 
the disturbing influences, and these must always be specially ascertained, and thus 
eliminated, in each chronometer, before anything like a general law is to be 
pronounced. Mouchez’s explanation is affected by his desire to explain everything 
by temperature, and would do, as it stands, only for under-compensated chrono- 
meters. Ansart-Deusy has an equal tendency to explain everything by magnetism 
—as we shall see further on—so that his interpretation cannot claim very much 
confidence either. , 
The result of all these observations and discussions is, that systematic observa- 
tions of changes of rate with changes of place—especially of ‘‘land and sea 
rates,” on board steamers as well as sailing vessels—are still wanting, and that it 
would be highly valuable to extend them over as long intervals and as many 
chronometers as possible. The chronometers ought to be well compensated, and 
their compensation errors (or temperature errors) determined as often as possible. 
And the most scrupulous account is to be given as to all circumstances of possible 
effect—temperature to be read in max. and min. daily; position, proximity of 
iron, &c.; ship’s course, ship’s motion, and so on; it is impossible to be too 
detailed in this respect. If practicable, compass observations ought to be made in 
the chronometer’s place in different positions of the ship as to the magnetic 
meridian, the reason for which precaution will be seen from the following 
parts of our investigation. 
