280 Hie Fhilosophical Society of Glasgow. 



tioii.* If, now, we conceive an elevated conductor, first belonging to 

 the earth (§ 1), to become insulated, and to be made to throw off, and 

 to continue throwing off, portions from an exposed position of its own 

 surface, this part of its surface will (julckly be reduced to a state of no 

 electrification, and the whole conductor will be brought to such a poten- 

 tial as will allow it to remain in electrical equilibrium in the air, with 

 that portion of its surface neutral. In other words, the potential 

 throughout the insulated conductor is brought to be the same as that 

 of the particular equi-potential surface of the air, which passes through 

 the point of it from which matter breaks away. A flame, or the heated 

 gas passing from a burnmg match, does precisely this : the flame itself, 

 or the highly heated gas close to the match, being a conductor which is 

 constantly extending out, and gradually becoming a non-conductor. 

 The drops into which the jet issuing from the insulated conductor, on 

 the plan introduced by the writer, produce the same eflects, with more 

 pointed decision, and with more of dynamical energy to remove the 

 rejected matter, with the electricity which it carries, from the neighbour- 

 hood of the fixed conductor." 



* Through some misapprehension, Mr. Delmann himself has not perceived that his 

 own method of observation really consists in removing a portion of the earth, and bringing 

 it insulated, -n-ith the electricity which it possessed m situ, to be tested within doors, other- 

 wise, he could not have objected, as he has, to Peltier's view. 



