Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . asses, indicatesa corresponding diminution. When the whole cur-rent was made to pass through the instrument, themagnetizing power in one experiment was 24,400grs.; that is, the electro-magnet employed attracted 38 D AVIS S MANUAL, its armature with a force equivalent to this following table will show the reduction of thisamount, when fine wires of various metals were em-ployed in the way above described. Magnetizing Pojver. Reduction. 7,350
Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity . asses, indicatesa corresponding diminution. When the whole cur-rent was made to pass through the instrument, themagnetizing power in one experiment was 24,400grs.; that is, the electro-magnet employed attracted 38 D AVIS S MANUAL, its armature with a force equivalent to this following table will show the reduction of thisamount, when fine wires of various metals were em-ployed in the way above described. Magnetizing Pojver. Reduction. 7,350 ,180 8,800 12,046 12,820 16,600 17,010 The conducting power of the metals is, of course,in proportion to their reduction of the magnetizingpower of the collateral current. The alloy of silverwith a little copper used in coinage, is the best con-ductor of the metals tried, and platinum the Powder Cup. In fig. 26 is represented alittle instrument designed to show the heating power Fig. 26, Silver coin,Copper,Pure silver,Brass, .Gold coin,Iron, . .Platinum, . 17,050 grs. 16,220 . 15,600 . 12,354 . 11,580 . 7,800 ^ . 7,390. of the battery current. Two copper wires, woundwith cotton thread, except at their ends, are joinedby a short piece of fine platinum wire. These wirespass through the bottom of a small glass cup, C, sothat the platinum wire lies free in its cavity. On VOLTAIC GAS PISTOL. 39 putting a little gunpowder into the cup, C, and thenconnecting the copper wires with the poles of thebattery, the platinum will become heated, in conse-quence of the flow of the ciUTcnt through it, so as toinflame the powder. The recent discovery of gun-cotton has a very useful application to this instru-ment, and to the galvanic battery generally, as ameans of igniting explosive compounds. The tem-perature at which gun-cotton explodes being onlyabout 360° P., requires a comparatively slight ele-vation of temperature in the wire. For blastingor submarine explosions, this wi
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectmagnetism, bookyear18
