16 
MINUTES OE PROCEEDINGS OE 
The weight is fixed and released in the following manner (Fig. 5) :— 
AB, CD, are two straight pieces of steel, screwed down at E and F; the 
latter (CD) being allowed to pivot freely around F, AB being fixed. 
Eig. 5. 
A strong spring ( G) attached to the keeper (H) of an electro-magnet (K), 
can be inserted at pleasure between the steel arms at B and D\ thus 
causing the opposite ends (AC) to close, and grip the steel plate (B, Fig. 4) 
of the weight. In this position, the keeper of the electro-magnet is a short 
distance from its poles, and when the current circulates is drawn down, 
bringing with it the steel spring (G). The pressure being thus removed 
from B and D, the weight is released, and falls between the cylinders. A 
slight spring (L) assists in releasing the weight. 
The magnet (K) is in electrical communication with two binding screws on 
the bed of the instrument. 
The Screens 
are constructed on the same principle as those of Professor BashfortlPs— 
viz., that the electric communication is immediately re-made, after being 
broken by the shot in passing through, so as to allow the next screen to 
register, and so on; but they differ slightly in construction, in order to take 
advantage of the circumstance that the induced spark is brighter and stronger 
when the primary current is broken between platina points. 
To make a screen suitable for experiments for a carbine, cut out rect- 
