PROCEEDINGS OP THE FARMERS' CLUB. 245 



The objection to insulation was, that it permits an excessive 

 electrical disturbance within the building under the influence of 

 a thunder cloud, until, at the instant of the discharge, the equi- 

 librium of the building itself can only be restored by an explo- 

 sion between the rod and the house. It was immaterial whether 

 the discharge be from the cloud to the earth, or from the earth to 

 the cloud ; the insulators in both cases equally interfered with 

 the true office of the rod, which is, or should be, to neutralize 

 any electrical disturbance within the building, by gradually 

 taking off any excess, or supplying a deficiency as may be required. 

 The electrical activity refered to, was induced solely by the 

 cloud, and the passage into the building from the earth, of cur- 

 rents of electricity in a rarified state, which flow silently without 

 producing any mechanical effects. The insulation prevents these 

 rarified currents from flowing ofi" freely, by means of the rod, to 

 the atmosphere, and retains the fluid within the building, until 

 there is a sufficient quantity to overcome the barrier presented by 

 the insulators, and it bursts out with an explosion. He had seen 

 this in many cases, one of which occurred to him where more 

 than half of the insulators were broken by the discharge, and 

 where, if the rod had not been insulated, he believed no harm 

 would have been done. Insulators prevent the rod from acting 

 efficiently as a distributer of electricity. A discharge of light- 

 ning is the passage of an excess of electricity from one body to 

 another body, or mass of matter which is deficient ; when the 

 discharge reaches the negative body, it divides and subdivides, 

 until it is equally diffused through it. In the case of a discharge 

 of lightning from the cloud, received upon an insulated lightning 

 rod, there is no provision for the communication to the building 

 itself of the quantum of electricity which, in common with all 

 other matter in the neighborhood, it requires to restore it to its 

 natural state of equilibrium, and that quantity must therefore 

 leave the rod and enter the building with an explosion. By the 

 exercise of skill and judgment, the rod can be so connected with 

 the building, and so arranged as to distribute the fluid to the 

 building in such minute portions as to do no harm. 



[In answer to an inquiry here, Mr. Quimby said that he used 

 rods three-eighths of an inch square. The manner of putting up 

 the rods was decided by the position, size and requirements of 

 the building.] 



Mr. Dickinson inquired if the attraction of a lightning rod, 



