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 LVI. Intelligence and Miscellaneous Articles, 



ON A NEW THERMO-ELEMENT. BY M. S. MARCUS. 



THE author has given the following account of the properties and 

 construction of his new thermo-element : — 



1 . The electromotive force of one of the new elements is -^th of 

 that of a Bunsen's element, and its resistance is equal to 0'4 of a 

 metre of normal wire. 



2. Six such elements can decompose acidulated water. 



3. A battery of 125 elements disengaged in a minute 25 cubic 

 centims. detonating gas ; the decomposition took place under unfa- 

 vourable circumstances, for the internal resistance was far greater 

 than that of the interposed voltameter. 



4. A platinum wire half a millim. in thickness introduced into the 

 circuit of the same wire is melted.. 



5. Thirty elements produce an electro- magnet of 150 pounds 

 lifting-force. 



6. The current is produced by heating one of the junctions of the ele- 

 ments, and cooling the second by water of the ordinary temperature. 



To construct this battery, it is necessary, on the one hand, to pro- 

 cure two electromotors suitable for a thermo-element, and, on the 

 other, to have such an arrangement of the elements, and of the means 

 for heating and cooling, as will ensure as favourable a result as pos- 

 sible. The former constituted the physical, the latter the construc- 

 tive part of the problem. 



In solving the first part of the problem it was the author's endea- 

 vour — 



a. To use such thermo-elements as are constructed of metals as 

 far apart as possible in the thermo-electric series, and 



b. Such as permit great differences of temperature without using 

 ice, — which is only practicable if the bars possess as high fusing-points 

 as possible. 



c. The material of the bars must not be costly, and the bars 

 themselves must be easily constructed. 



d. The insulation used for the elements must be able to resist 

 high temperatures, and must possess sufficient solidity and elasticity. 



As neither the usual bismuth-antimony couples nor any combi- 

 nation of the other simple metals satisfy these conditions, M. Mar- 

 cus availed himself of the circumstance that alloys, in the thermo- 

 electric pile, do not stand between the metals of which they consist, 

 and was thereby led to the following alloys, which completely satisfy 

 the above requirements : — 

 For the positive metal — 



10 parts of copper, 

 6 „ zinc, 

 6 „ nickel. 

 An addition of one part of cobalt increases the electromotive force. 

 For the negative metal — 



1 2 parts of antimony, 

 5 ,, zinc, 

 1 part of bismuth. 



