Ther′mo-e-lec′tric Bat′tery.
（
Electricity.) One in which an electric current is established by applying heat or cold to one of the junctions in a circuit composed of two different metals.
It was first shown by Seebeck of
Berlin in 1821.
See
Deschanel's “Natural philosophy,” Part III.
pages 652, 653.
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Thermo-electric pile. |
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Thermo-electric pile. |
Figs. 6347,
6348, illustrate ordinary forms of the apparatus.
Fig. 6349 shows the battery or pile of Melloni.
b c are an enlarged view and a section of the elements.
At the Exposition of 1867 were exhibited three batteries of this class: those of Farmer, American;
Marcus, Austrain; and Ruhmkorff,
French.
The former consists of strips of copper and wedge-shaped blocks of an alloy arranged alternately in the form of a ring.
The strips of copper are soldered at each end alternately, and insulation between the metals is effected by interposed plates of mica.
Heat is applied to the inner edge of the ring by means of a circular gas-burner.
It was stated that thirty-six elements of this battery were equal to one of
Grove's.
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Melloni's thermo-electric battery. |
In the battery of
Professor Marcus, the positive and negative elements are both alloys: the former consisting of 10 copper, 6 zinc, and 6 nickel; and the latter of 12 antimony, 5 zinc, and 1 bismuth.
The bars are arranged after the manner of the rafters of a house, and soldered together at their alternate extremities, separated by a slight interval, no insulating material being
[
2546]
employed.
Their lower ends are immersed in water heated by a spirit-lamp.
65 pairs of this battery were capable of developing a lifting force of from 25 to 50 kilogrammes in an electromagnet.
Becquerel's battery was invented in 1865.
He discovered that artificial sulphide of copper when heated to 200° or 300° Centigrade is strongly positive, and that a couple formed of this substance and metallic copper has nearly ten times the force of the ordinary antimony and bismuth couple.
This is remarkable, as the native sulphide is strongly negative.
The metal actually used for the negative element is not pure copper, but an alloy of 90 copper and 10 nickel (German silver). The elements are arranged in a manner resembling that of
Marcus, their ends being immersed in water heated by means of a gas-burner.
Eight or nine of these elements are considered by
M. Becquerel to be equal to one of
Daniell's. With fifty couples an electro-magnet has been made to sustain a weight of 100 kilogrammes (220 lbs.）
