THE FORCES OF INORGANIC NATURE. 231 



as both are now slightly charged, there will be slight repulsion. Charge both 

 balls to their full capacity, and we have strong repulsion, because now the repel- 

 lent element is in excess on both. Here, as all along, we find the heat element 

 self-repellent. We have the clearest proof that attraction results from the affinity 

 between the two elements. In attraction, we may be allowed to assume that the 

 potency is in the heat. 



Now let us for a moment look at the question : Is the heat of friction from 

 electricity ? This question should now require but a short argument. Observe; 

 it would have been impossible to have insulated Count Rumford's cannon. And 

 the heating of that water was a small affair, when we consider the nature of 

 electricity. It will be found that friction between bodies that hold electricity 

 with a degree of rigidity will develop most heat. And it will be found that 

 every lubricator is something for which electricity has the least possible affinity. 

 Glass is coated with electricity, and water is charged with it. So when Prof. 

 Tyndall pours water, or mercury, from glass to glass, and tells us the motion makes 

 heat, we may object. So again, not only his bullet, but his anvil and his sledge 

 are all coated with electricity; and when he tells us that the sudden destroying of 

 ^notion makes heat, we may object. The woodman's saw, when not greased, has 

 a blanket of electricity on either side of it. Of course it will heat by friction. 

 When the woodman gives it a coat of grease he does the best possible thing to 

 keep the electricity off. If you can get an electric spark by rubbing a cat's back, 

 or by touching your toe to the carpet, no wonder you can get it by rubbing two 

 sticks together, or from the steel and flint. You will observe most of Prof. Tyn- 

 dall's beautiful experiments, illustrating the dynamic theory of heat, were made m. 

 connection with the electric pile and the magnet and coil. He tells us that work- 

 ing a saw through a strong current of electricty, it seems as though it were being 

 pulled through cheese, and that it soon becomes very hot. All of which is as we 

 might expect. If the reader wants more proof that the heat of friction is from 

 electricity let him look it up for himself. He will find it about him on every 

 side. 



Electricity moving unimpeded gives us no heat. In that case its heat con- 

 tinues latent. It is when it is crowded that heat is given off, as every electrician 

 knows. When it gives- us heat some electricity is destroyed, and as a result heat 

 is set free. So color-rays are destroyed and heat is set free. So oxygen is 

 destroyed and heat is set free. Electricity is easily destroyed when it is massed 

 on solids. It can be done by concussion, by friction, and by chemical actions 

 that either appropriate its matter and free its heat, or appropriate its heat and 

 free its matter. It can be destroyed by its own crowding as it passes over defec- 

 tive points of the conducting medium, or by its leaps as it passes from proximate 

 conductors. As the sparks pass from one body to the other, minute particles of 

 the first body are deposited on the second. This shows the strong attraction by 

 which the electricity clothed itself with particles of the metal over which it passes. 

 It shows also that the crowding and concussion destroyed electricity, and caused 

 a depositing of its matter, and as you might expect the result is great heat. As 



