ELECTRICAL MACHINES AND APPARATUS. 23 



No. 



508 Fig. 374, medical jar, - - .-.:,.*# , - $ 2.50 



509 Fig. 374, medical electrometer, - 2.00 



510 Fig. 375, pair of directors with glass handles 



for administering electricity medically, - . 2.50 



511 Wooden point, ditto, - 0.25 

 - 512 Amalgam for electrical machines, per box, - 0.12 



513 Brass chain for conducting electricity, per foot, 0. 4 



514 Gold cord, " " " " 0. 4 



515 Pith images, dressed, for image plates, each, 0.75 



516 " plain, " " " 0.13 



517 Paper figures for image plates, each, - 0.12 



518 Pith balls for electrical purposes, per dozen, 0.25 



519 Pith of elder, per stick, six inches long, 0. 4 



520 Brass balls with stems, - 15 cts. to 0.50 



521 Brass balls, assorted sizes, 12 cts. to 2.00 



522 Electrical cylinders, five inches diameter, $1 ; 



six inches, ditto, $1.25 ; seven inch, ditto, 

 $1.75 ; eight inch, ditto, $2.50 ; ten inch, 



ditto, - 4.00 



523 Glass pillars, for conductors, each, six inches 



long, 38 cts. ; eight inch, 50 cts. ; ten inch, 



75 cts. ; twelve inch, - - f r - 0.87 



524 Glass stool feet, each, ,. 38 cts. to 0.50 



525 Glass rods, per pound, 50 cts. to 0.75 



526 Rod of sealing wax, one and a quarter inch in 



diameter, for rubbing, - ... 1.00 



527 Glass handles, each, - - 38 cts. and 0.50 



528 Glass tube for rubbing, 12 cts. to 0.50 



529 Best tin foil for electrical purposes, square 



foot, - - ... o. 6 



530 Best tin foil, ditto, per pound, - - - 1.00 



531 Cement for electrical purposes, per pound, 0.50 



532 Price of copal, for rubbing, - 25 cts. to 0.50 



533 Price of amber, for rubbing, j ,r - - 0.50 



VOLTAIC OR GALVANIC BATTERIES, <fec. 



534 Fig. 380, simple galvanic series in porcelain 



cups, each series, - - 0.25 



