366 Miscellaneous Intelligence. 
plete circumference, until the directive power of the earth, by 
gaining the ascendancy, caused the arcs of vibration successively to 
diminish ; the needle ultimately obtaining a position coincident with 
the meridian, where it continued in a state of tremulous motion as 
before. 
Mr. Harvey remarks, that the quantity of steel contained in the 
chronometer was truly remarkable, and no part of it was destitute 
of vigorous polarity. Every screw displayed its influence, and of 
which there were ten large, and several small ones, in the frame 
alone. The chain also, the axles of the different wheels and pinions, 
the arbor of the fusee, the balance and its spring, exhibited the same 
intense and active power. Nor did this polarity partake of the 
transient character of that imparted by induction from the earth to 
soft iron, but was permanent, undergoing no sensible alteration frem 
change of position. 
‘ 8. Influence of Magnetism on the Rates of Chronometers.—This 
interesting and curious subject continues to interest philosophers, and 
Mr. Harvey, in the XIXth and XXth Numbers of the Edinburgh 
Philosophical Journal, has two papers, devoted to the consideration 
of the changes which time-keepers undergo, altering their positions 
with respect to the attracting force, 
A pocket chronometer, having a very steady and uniform rate of 
+20".4, was placed with its main spring nearly in contact with the 
magnet, and with the magnetic power directed through its centre, 
when the rate altered to +65".1; but on moving the centre of the 
main spring 90° from the preceding position, so as to cause the mag- 
netic power to be transmitted through the centre of the balance, the 
rate immediately declined to —23'.2; and on turning the time- 
keeper another quadrant, so as to remove the centre of the main- 
spring 180° degrees from its first situation, the rate again rose to 
+43".4; and when through another quadrant, the attractive force 
being in this situation transmitted nearly through the centre of the 
balance, the rate became —2".6 ; and on restoring it to its first posi- 
tion +72".7. When the time-keeper was detached, its rate returned 
to +18”.2. Similar experiments with another chronometer, having 
a detached rate of —2’.0, produced in situations corresponding to 
the last, the rates +10”.0, +31; -+5”.0, and —1".1. From 
these experiments, Mr. Harvey deduces, that an increase of rate 
resulted from the direct transmission of the magnetic influence through 
the centre of the main spring ; and a diminution thereof, when the same 
power passed nearly through the middle of the balance and its spring. 
Mr Harvey has, however, not only determined the effect of the 
direct transmission of the magnetic power, through the centre of the 
main-spring, but also that produced by its partial operation. For 
this purpose, the first of the before-mentioned chronometers was so 
