667315-1886-Verification-of-the-Unifilar-Magtometer-Elliott-Bro--No-55- — Page 1

466

THE HONGKONG GOVERNMENT GAZETTE, 29TH MAY, 1886.

GOVERNMENT NOTIFICATION.-No. 200.

The following Report of the Director of the Observatory on the Verification of the Unifila Magnetometer Elliott Brothers, No. 55, is published for general information.

By Command,

Colonial Secretary's Office, Hongkong, 29th May, 1886.

FREDERICK STEWART,

Acting Colonial Secretary.

ON THE VERIFICATION OF THE UNIFILAR MAGNETOMETER ELLIOTT BROTHERS, No. 55.

Observed time of one vibration of the magnet expressed in seconds.

T.

Ꭲ,

T. corrected for rate of chronometer and arc of vibration.

T

T1 corrected for torsion and induction and reduced to Oo cent.

T.

P

a

Observed and corrected time of one vibration with inertia cylinder in position. Daily rate of chronometer in seconds.

Semi-arc of vibration at the beginning of the observation in parts of radius.

""

end

""

}"

>>

"

""

Ratio of the force of torsion of the suspending thread to the magnetic directive force.

Temperature in degrees centigrade.

Reduction to O° of the magnetic moment of the magnet.

Moment of inertia of the magnet with its appendages.

a

""

H

F

qt+q't

K

m

W

1

Length

""

"

d

Diameter

""

>1

7

3.14159.

μ

Magnetic moment

"2

""

27

Weight of the inertia-cylinder in grammes.

centimeters.

""

17

"}

Increase in the magnetic moment produced by the inducing action of a magnetic force equal

to one C. G. S. unit.

r = Observed distance between centres of deflecting and deflected magnets.

r

r. (1+0.000 018 t) r. reduced to 0o.

Ua

Observed angle of deflection.

P

X

- A constant depending upon the distribution of magnetism in the two magnets.

Horizontal component of the earths magnetic force in C. G. S. Units.

r3 sin u..

corrected for induction and reduced to 0°.

m

X

(1 − 1).

A

A1

X1

39

"

Mean value of from deflections at 30 centimeters made during the year.

40

"

""

"

The formula for the calculation of the value of the horizontal component of the earth's magnetic force and of the value of the magnetic moment of a magnet are:-

T, = T. (1786400

aa

> 16

where the upper sign is used, when the chronometer is gaining, and the lower, when it is losing.

H

T = T}? (1 + =

· ·

F -qt-q' t2 + μ

Xo)

m。

mX==

TK T

X.

r sin u

m

(1 +

X1

+ qt + q' t2)

m1

X

꽃-꽃 (1-2)

12 d T2

K = W (12 + 16 ) T2 - T2

P

100 (A—A1)

A A

9-16