ELECTRICAL APPARATUS. 

 Fig. 337. Fi. 333. 



293 



Fig. 340. 



Spotted Jar. (Fig. 339.) This is fitted 

 up like the Ley den phial, only the tin-foil 

 coating is gummed on in little square pieces 

 at some distance from each other ; so that 

 when the bottle is charged in the dark, the 

 sparks will be seen flying across the spaces, 

 from one square to another. If it be dis- 

 charged gently, by bringing a pointed wire 

 gradually to the knob of the jar, the fluid 

 will pleasingly illuminate the uncoated parts, 

 and make a crackling noise in passing the 

 spaces. Price, pint, $2.25. 



" quart, $3.00. 



The Egg Stand. (Fig. 340.) This con- 

 sists of a wooden frame, with a piece of metal 

 let into the bottom ; a chain attached to this 

 is connected with the outside of a Leyden 

 jar. There are three wooden slides to hold 

 as many eggs. A wire and ball pass through 

 the upper part of the frame, so as to touch 

 the top egg, and the eggs are to touch each 

 other. A shock is passed through the eggs 

 by touching the upper ball with a discharg- 

 ing rod, which reaches to the inside of the 

 charged jar, whose outside is united to the 

 chain at bottom. The eggs will become 

 beautifully luminous, and the shock in pass- 

 ing will make a sound as if the egg shells were broken, as 

 indeed they will be if the shock be large. A quart jar is 

 quite sufficient for this experiment. The eggs, if eaten im- 

 Zo 



