308 SEC. 10. ELECTRICITY. 



1286. Nobili's Thermo-Electric Pile, of 54 pairs of 

 bismuth and antimony bars, soldered alternately together ; the 

 smallest difference of temperature between the two faces of the pile 

 develops a current, readily indicated by a suitable galvanometer. 



Elliott Brothers. 



1235c. Apparatus intended for producing Thermo-electric 



Currents in a special manner. 



Imperial University of St. Petersburg. 



It consists of ten straight electro-magnets, with their poles joined alter- 

 nately so as to form a zig-zag. The iron cores arejiot in direct contact but are 

 connected by small brass cylinders to which they are soldered at their extremities. 

 These small cylinders carry brass plates and rods ' placed alternately. When 

 the apparatus is to be used, these plates are heated approximately up to 100 

 centigrade ; the brass rods are cooled with crushed ice, and then the galvanic 

 current of a six element battery (carbon, zinc, chromic liquid,) is passed 

 through the bobbins of the electro-magnets, odd or even numbers. The 

 thermo-electric current produced \>y the iron cores produces a strong devia- 

 tion of the needle of a sensitive galvanometer of small resistance. 



The fact of the heterogeneousness of magnetised metals and non-magnetisc 

 metals was discovered by Sir W. Thomson. The apparatus here described is 

 constructed by Prof. T. Petrouchevsky, Professor at the University of St. 

 Petersburg. The first experiments made with this apparatus, slightly altered 

 however, have been briefly described in Russian in the " Journal of the Russian 

 " Society of Chemistry," and in that of " The Physical Society of the Univer- 

 " sity of St. Petersburg," Vol. 6, Section Phys., p. 107 (1874). 



1287. Hoe's Thermo-electric Battery of 96 pairs. Con- 

 venient for lecture experiments. George Gore, F.R.S. 



Attains its maximum power in about one minute. May be heated to low 

 redness. Decomposes water freely. Will excite an electro-magnet to sus- 

 tain 2 cwt. It has an arrangement, or " current transformer," by means of 

 which its entire power can be employed with three different combinations of 

 its elements, viz., as 96 by 1, 48 by 2, or 24 by 4, and changed instantly from 

 one combination to another. The connexions of the " transformer " require 

 no cleaning. Made by W. J. Hauck, Vienna. 



1288. Small Single-cell Apparatus, with platinum-plates, 

 for showing the thermo-electric properties of liquids. 



George Gore, F.R.S. 

 (See Philosophical Magazine, Jan. 1857.) 



1289. Single-cell Apparatus, for examining the thermo- 

 electric properties of liquids. George Gore, F.R.S. 



(See Proceedings of the Royal Society, 1871.) 



1290. Large Single-cell Apparatus, with platinum-plates, 

 for showing the thermo-electric properties of liquids. 



George Gore, F.R.S. 



