on the Mates of Chronometers. 3 
be regarded as considerable, when the remarkable changes the 
rate underwent in the different positions of the machine is fully 
considered. The chronometer was allowed to remain four days 
in each situation ; and when finally detached from the magnet, 
its rate returned to + ; a quantity not very dissimilar to 
that which it possessed before its application to the magnet. 
The last-mentioned rate continued steady and uniform for se- 
veral succeeding days. The preceding results are recorded in 
the following Table : ' 
Situation of Chronometeh (A). 
Daily Hate. 
Detached, 
+ 20" 4 
Fig. 1. Main-spring nearly in contact with the magnet, 
and the attractive power transmitted through its centre, 
+ 65" 1 
Fig. 2. Centre of the main-spring removed 90° from the 
preceding position, and the magnetic power transmitted 
nearly through the centre of the balance and its spring, 
23" 2 
Fig. 3. Centre of the main-spring 180° from its first situa- 
tion, and the magnetic power transmitted through its 
centre, _ . - _ 
+ 43". 4 
Fig- 4. Centre of the main-spring 90° from its first situa- 
tion, and the magnetic power transmitted nearly through 
the centre of the balance and its spring, 
— 2".6 
Fig. 1. Main -spring nearly in contact with the magnet, and 
the attractive power transmitted through its centre, 
+ 72".7 
Detached, 
+ 18" 2 
The same experiments were afterwards repeated with a box- 
chronometer (B), (detached from its case), having a steady and 
uniform rate of — 2".0. On being placed in the situation de- 
noted by Fig. 1., the detached rate was changed to + 10".0; 
but being turned, as in Fig. 2., the last-mentioned rate declined 
to 4- 3".l ; and when brought into the position of Fig. 3., the 
rate increased to -f 5^'.0 ; and w^hen lastly moved, so as to cor- 
respond in situation with Fig. 4., the rate again declined to 
— l".l. Another series of observations, in similar positions of 
the chronometer, gave for Fig. 1. a rate of + 1 1".7 ; for Fig. 2., 
a daily increment of + 3".4 ; for Fig. 3., an average increase of 
+ 7 ". 0 ; and for Fig. 4., a rate of + 1".4, each result being a 
A 
