MAGNETIC INSTRUMENTS. 25 

 No. 



561 Fig. 400, set of twelve, extra large, as used 



by Prof. Morse for telegraph, - - $ 20.00 



562 Fig. 400, set of eighteen, extra large size, - 30.00 



563 Fig.- 402, apparatus for the decomposition of 



water by battery, .... 0.75 



564 Fig. 403, ditto for collecting the separate 



gases, - - - $4.00 and 5.00 



565 Fig. 404, ditto, larger size, 5.00 



566 Fig. 405, ditto, with V tube, - $1.50 to 2.00 



567 V tube, with platina wires for decomposition, 0.50 



568 Fig. 406, decomposition tube, - $1.25 to 1.75 



569 Conducting wires with boxwood charcoal 



points for ignition, - - - - 0.12 



570 Conducting wires with steel watch spring, or 



iron turnings for ignition and burning, - 9.12 



571 Fig. 407, powder cup, - - 0.50 



572 Fig. 408, pistol to fire by galvanic battery, - 3.00 



MAGNETIC INSTRUMENTS. 



573 Fig. 409, artificial bar magnets, each, four 



inch, 25 cts. ; eight inch, SOcts. and 75cts. ; 



ten inch, 75 cts. and $1 ; twelve inch, $1 and 1.50 



574 Fig. 410, artificial horse-shoe magnets, two 



inch, 31 cts.; three inch, SOcts. ; four and 

 a half inch, 7octs. ; six inch, $1 ; eight inch, 

 $1.50 ; ten inch, - - 2.25 



575 & 6 Fig. 411, compound horse-shoe magnet, 



six inch, 3 bars, $5 ; eight inch, do., $7.50 ; 

 ten inch, do., $10 ; twelve inch, do., $12.50 ; 

 twelve inch with five bars, - - $16 to 20.00 



577 Figs. 412 and 413, magnetic needles, from 



four and a half to five inches, 38 cts to 1.00 



578 Magnetic needles with agate or ruby caps, 



four to twelve inches, - $2.50 to 5.50 



579 Fig. 412, wood stand with steel point, 25 cts. ; 



brass stand do., - - 1.00 



580 Fig. 414, astatic needle, - - - $2 to 5.00 



