( 360 ) 
Art. XXIII. — Descri'ption of a Magnetimeter^ being a New 
Instrument for Measuring Magnetic Attractions^ and Find- 
ing the Dip of the Needle ; with an Account of Experiments 
made with it. By William Scoresby, Esq. iun. F.R. S. E, 
M. W. S. &c. 
In the month of December 1819> Mr Scoresby communicated 
to the Royal Society of Edinburgh, a description of a new instru- 
ment for ascertaining the Magnetic Dip. Having made very 
considerable improvements in the apparatus, by means of which 
some curious results on the magnetic laws, especially those that 
relate to the production and annihilation of magnetism in iron, 
have been obtained, he recently submitted to the Society a draw- 
ing and description of his improved instrument, together with an 
outline of some of the most interesting experiments made with it. 
* This instrument consists of a small table of brass, inches 
square, and 3| inches high, having a plate of brass attached to 
it by hinges, and moveable by means of a wheel and pinion, 
through an arch of 250° of a vertical circle. This plate has a 
small straight groove running from end to end, for the purpose 
of receiving bars of metal, the polarity of which is to be deter- 
mined. These bars are readily fixed to the plate, by being slip- 
ped through a circular aperture in the end of a spring, which, 
perforating the moveable plate, and acting downward, firmly 
embraces any substance laid along the groove. The angular 
position of the moveable plate is marked by a graduated circle, 
screwed upon the side of the table. On the brass table is pla- 
ced a moveable flat plate of brass, divided into rhumbs and de- 
grees, and furnished with a magnetic needle, with an agate cap 
traversing on a brass or steel point. The needle can be changed 
according to the nature of the circumstances; a very light 
and strongly magnetized one being used in delicate experiments. 
The compass or plate carrying the needle, being moveable, its 
distance from the bar resting on the moveable plate, can be var. 
ried at pleasure. The centre of the hinges is one- tenth of an 
inch above the level of the table ; the magnetized needle stands 
at the same elevation ; and the bars in use being one-fourth of 
an inch in diameter, are sunk in the groove of the moveable 
