12 
AN APPARATUS FOR OBSERVING SPLASHES. 
dimensions of ordinary drawing pencils, and wliicli are pivoted 
on horizontal axes! The lever A A' carries at the end A a watch- 
glass on which the drop to be let fall is placed ; this glass is 
smoked to prevent the adhesion of the liquid when a water drop 
is used. The lever BB' carries at the end B a small wire ring 
on which the ivory sphere to be simultaneously let fall is placed. 
The other ends of the levers are provided with light iron 
armatures A' and B', which are attracted and held down by 
the poles of the electro-magnet C against the action of springs 
consisting each of an india-rubber ring stretched across two pegs 
at E and E'. AVhen the current of the electro-magnet C is cut 
off these springs toss up the ends A' and B' of the levers, and 
the support of the drop at A and of the ivory sphere at B is 
thus removed simultaneously, so that drop and sphere begin 
to fall at the same instant. 
The ivory sphere in its fall strikes the plate D at the end of 
the lever DG, whose height can be adjusted by sliding the block 
which carries it up or down the vertical rod 0, whose upper 
support has been removed in the drawing for the sake of showing 
the part of the apparatus which it would conceal. This lever 
DG carries on its lower side a ^datinum wire, one end of which 
is bent down into a mercury cup, while the other crosses at right 
angles a second and fixed wire. AA hen these twm wares are in 
contact an electric current can pass from the fixed ware to tlie 
mercury, but the moment the plate D is struck the wire of the 
lever is lifted and the contact broken. To prevent the two wires 
from welding together at the point of contact, the lower is kept 
cool by being laid on a stout strip of copper ; while to secure a 
good contact, the end G of the lever is held by an indiarubber 
band GT. The current w'hich is thus broken has passed through 
a second electromagnet H, by w’hose attraction the lever KK is 
kept dowai against the action of a spiral spring at L. When 
the current of this magnet is broken, the motion of the lever 
