Wells's principles and applications of chemistry; . duce what has been called a perpetual mo-tion. Two piles, P N, are placed in such a positionthat the positive extremity of one pile is opposite andnear to the negative extremity of the other. Be-tween them a Hght pendulum is placed, vibrating onan axis and insulated on a glass pillar. This pen-dulum is alternately attracted to one and then to theother, and thus rings two httle bells connected withthe positive and negative a similar manner, voltaic piles have been constructed entirely of vege-table substances, without resorting to the
Wells's principles and applications of chemistry; . duce what has been called a perpetual mo-tion. Two piles, P N, are placed in such a positionthat the positive extremity of one pile is opposite andnear to the negative extremity of the other. Be-tween them a Hght pendulum is placed, vibrating onan axis and insulated on a glass pillar. This pen-dulum is alternately attracted to one and then to theother, and thus rings two httle bells connected withthe positive and negative a similar manner, voltaic piles have been constructed entirely of vege-table substances, without resorting to the use of any metal by placing discsof beet-root and walnut-wood in contact, With such a pile, and a leaf ofgrass as a conductor, convulsions in the muscles of a dead frog are said tohave been produced. Other experimentalists have formed voltaic piles whollyof animal substances. 225. Practical Prodnction of Galvanic Electricity.—la tlie production of galvanic electricity for practical pur-poses, it is necessary to have a combination of tliree dif-. QxrESTiosrs.—^Describe the dry, or Zamboni s pile. May a voltaic pile be produced en-tirely of vegetable or animal substances ? What arrangement is necessary for the practi-cal production of galvanic electricity ? ELECTRICITY. 139 Fig. 64. ferent conductors, or elements^ one of which must bosolid and one fluid, while the third may be either solid orfluid. The process usually adopted is to place between two plates of differentkinds of metal a liquid capable of exciting some chemical action on one of theplates, while it has no action, or a different action upon the other. A com-munication is then formed between the two plates. 226. Galvanic Circuit.—When two metals capable ofexciting electricity are so arranged and connected that thepositive and negative electricities can meet and flow inopposite directions, they are said to form a galvanic cir-cuit, or circle. Such an arrangement is very generallytermed, also, a simple galvanic ba
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectchemistry, bookyear18
