Mechanical and General Science. 367 
placed, that a radial line proceeding from the centre of the time= 
keeper through the middle of the main-spring, might form an angle | 
of 27° with the longitudinal axis of the magnet. The consequence 
of this application was an immediate increase of +20".1, its de- 
tached rate, to +52".3 ; a quantity /ess than the mean of the two re- 
sults obtained from the direct transmission of the magnetic power 
through the centre of the spring, by +16".6. By pursuing this 
branch of the subject, the author of the experiments found, that the 
removal of the centre of the spring from the axis of the magnet, 
through equal arcs, appeared to produce proportional declensions of 
rate. In one experiment, the rates +68."9 and +43."4, pro- 
duced by the direct transmission of the attractive force through the 
eentre of the main-spring, and when this point was at its least and 
greatest distance from the pole of the magnet, are very nearly pro- 
portional to +50’.8, and +-33’.7, the rates obtained, when the ra- 
dial line proceeding from the centre of the time-keeper through the 
middle of the main-spring, formed respectively angles of 27° and 
153°, 
An exception to the above conclusions was discovered by Mr. 
Harvey, when experimenting with ancther chronometer, the accele- 
rations in the rate having taken place when the’ magnetic power was 
transmitted through the centre of the balance; and the retardations, 
when it passed through the middle of the main-spring ; and the 
author, when alluding to this anomalous result, properly observes, 
in the pursuit of experimental science, every result ought to be 
fairly and impartially recorded. The admirable maxim of Bacon, 
we cannot control Nature, uniess by making her manifest, should ever 
be present to the mind of the inquirer. 
The influence also of magnetized plates is illustrated by several 
experiments. ‘Iwo chronometers, when placed on a circular mag- 
netic plate, Jost by having XII turned from N. to E.; gained by 
being turned from EK. to S.; dost from S.to W.; and gained from 
W. to N.; the changes from plus to minus being alternate. It was 
found also, that the difference even of one-eighth of an inch, in the 
position of the chronometer on the magnetized plate, was constantly 
accompanied by a sensible alteration of rate. The rate was always 
augmented by moving it nearer to the north pole; and the most con- 
siderable alterations were found in the east and west positions of the 
time-keeper, whien the line drawn from the axis of the chronometer 
to the centre of the balance, was at right angles to the meridian of 
the magnetized plate. ‘Ihe smallest changes were also produced in 
those situations of the chronometer corresponding to north and south, 
the centre of the balance being in those positions of the machine, in’ 
the magnetic axis of the plate. 
9. On the Adaptation of a Compound Microscope, to act as a Dyna- 
meter for Telescopes. By C. R. Goring, M.D,.—It appears to me 
2C2 
