DISTRIBUTION OF RAINS. 143 



Mr. Perley. I proposed the question in regard to electricity 

 because it has frequently been remarked, that after a violent clap 

 of thunder, rain is apt to fall in larger quantity than before. 

 Frequently, a very heavy shower follows a discharge of electricity. 

 I do not know that one is the effect of the other, but we country 

 people think it is. 



Prof. Fernald. Electricity is one form of force, and this force 

 in the atmosphere that has been used up in the electric discharge 

 has been at the expense of heat. Heat and eleetricity are fre- 

 quently interchangeable. A force may develop itself as heat, 

 which, with slight modification, may be developed as electricity. 

 Electricity produces heat ; heat produces electricity. Now, 

 when there is an electrical discharge, there is an expenditure of 

 power, heat is used up, a reduction of temperature of the sur- 

 rounding air results, and rain consequently follows. 



Mr. Williams. I have been very much interested in this lec- 

 ture, and I regard this as a propitious moment for us farmers to 

 improve. I would like to "ask the Professor, how it is that our 

 northeast wii:d gives us rain? 



Prof. Fernald. I will answer that with pleasure. I have not 

 this evening taken up the subject of ocean currents at all. If you 

 were near enough to see the arrows on this map, you would see 

 here the warih Gulf Stream moving in the direction indicated by 

 tlie aiTows, and you would see also the Labrador current, a cold 

 surface current, coming down from the north. The latter is 

 charged with masses of ice, which float down into the warm Gulf 

 Stream, and are there melted. Now, this cold ocean current 

 passes inside of the Gulf Stream, next the coast, and hence, when 

 we have a wind from the northeast, it comes to us charged with 

 the vapor of this cold current. You all know how cold a north- 

 east storm is, and you have here the philosophy of it. The wind 

 has been charged from the vapor of a cold stratum of water. It 

 is sometimes the case that sailors, when in this cold current, ex- 

 posed to its severity, find the rigging of their vessel completely 

 coated with ice, and they themselves become so benumbed with 

 cold that they can scarcely control the vessel. What do they do ? 

 They sail directly down into tlie Gulf Stream, thaw out, and then 

 are ready to go back and encounter again the perils of that cur- 

 rent. This Labrador current accounts not only for the storms 

 that we have when the wind is northeast, but for the character of 

 those storms. 



