280 THERMO ELECTRTCITY. 



The experiments adduced show, that these 

 latter metals may be simply regarded as conduct- 

 ing media to thermo Electricity, that they offer 

 no specific resistance to the flow of current, and 

 may, therefore, be employed either in con- 

 junction with electro-positive, or electro-negative 

 metals. 



The results thus arrived at resemble much those 

 evinced by the experiments of Dr. Franklin and 

 others on the Tourmalin, in which ordinary Elec- 

 tricity was developed by heat alone, save that in 

 this instance the electricity resembles the voltaic 

 fluid, owing no doubt to the want of that complete 

 insulation among the molecules of the metals, 

 which is afforded by the Tourmalin. 



It is remarkable that no polar fluid, or 

 Electricity of any kind, is ever developed without 

 the employment of a crystalline, insulating, or 

 imperfectly conducting body. For in voltaic 

 arrangements, the Electrolyte is this non-con- 

 ducting medium ; in the cases just cited, the 

 Tourmalin was the intermediate polar body ; 

 in ordinary Electricity, the glass cylinder is 

 the non-conducting body, or " Electric," and in 

 thermo, and mechanical Electricity, (hereafter to 



