HydrO'Electrical Currents, 349 



tensity ; the annexed figure shews the side view of a 4-pair battery 

 arranged to be excited by flame. 



Fig. 2. 



^ L w L 



Ih 





d \ e ^ ^^ "l a 



a, a. Antimony bar 84 inches long; h, by bismuth bar 6 inches long ; 

 Cf the soldering of pure bismuth exposed to a heat a little lower than the 

 melting temperature of this metal. 



d, d, Slips of wood one-twentieth of an inch thick, coated with shell lac, 

 and inserted betwixt the bars to keep them from touching. Four pairs 

 of these bars are placed side by side, and kept apart by slips of wood 

 like dy d. Figure 3 represents the end view of the 4 combined pairs, 

 with the solderings necessary to complete 

 the electrical circuit ; a, h, c, d, the ex- Fig. 3. 



tremities of the antimony bars farthest 

 from the exciting flame ; c,/, g, h, the cor- 

 responding extremities of the bismuth bars; 

 a/, hg, ch, solderings to complete the elec- 

 trical circuit ; e i, the pole attached to 



bismuth bar ; d k, the pole attached to antimony bar. Weiglit of the 

 whole, 8 ounces. 



The advantage derived from placing the antimony bars side by side 

 la, that a small flame serves to excite the whole. The parts a, e (figure 2) 

 of the antimony bars, are enveloped in a blue de-oxydizing flame, where 

 they attain a temperature corresponding to the first degree of redness, 

 barely perceptible in the dark, and maintain at the soldering c (figure 2) 

 a heat little lower than the melting temperature of bismuth. Thus, be- 

 twixt the two extremities of the pile, a difference of temperature equal 

 to 300° of Fahrenheit, may be sustained by means of a small gas flame to 

 supply a powerful and equal current of thermo-electricity for months. 



9. In performing a number of chemical decompositions by the thermo- 

 electricity derived from the battery, figures 2, 3, they were found to be 

 subject to irregularities, which at first proved very perplexing ; during 

 4 months that the battery was in constant action, there appeared to be 

 a gradual loss of decomposing power. The action was commenced at the 

 end of the hottest part of the summer, and as the weather approached its 

 winter temperature, the difference betwixt the hot and cold ends of the 

 bars had augmented about 25 degrees, consequently the battery was ge- 

 nerating a current of higher intensity (for the electro-motive force has 

 been proved to vary witli the temperature). Any gain, however, from such 

 a source, is entirely annihilated, if the temperature of the decomposing 

 cell be allowed to follow the weather. Electrolysis by thermo-currents, 

 from the low intensity of the electricity, are keenly sensitive to any 



VOL. XXXV. NO. LXX. — OCTOBER 1843. 2 A 



