1868.] SMALL WOOD — ON OZONE. 375 



which has made most rapid strides within the past few years ; it 

 embraces subjects curious and interesting from their close relation 

 to almost every other branch of natural and physical investigation. 

 It may be true that the ancients were familiar with some of its 

 peculiar properties — that property possessed by amber, which, 

 when smartly rubbed on a piece of linen or cloth, attracted light 

 substances when thus excited by friction — the shock felt on 

 touching the electric fish — and the appearance of sparks which are 

 seen to issue from the human body under some peculiar conditions, 

 are among the familiar and earlier examples of electrical knowledge, 

 and it was at this period of history, and by slow degrees, that the 

 knowledge thus acquired was reduced to something like system. 

 That toy — the kite — which the renowned Benjamin Franklin 

 floated under the canopy of the American firmament in June, 

 1752, caught from the storm-cloud the electric sparks which are 

 now, in our day, made subservient to man, to flash our messages 

 of commerce and daily wants along the slender pathway of a 

 single wire. 



Recent investigations have brought to light many interesting 

 facts in connection with the sources of atmospheric electricity, 

 which is said to have a certain bearing on the subject under our 

 present consideration. Some of these have their origin in 

 evaporation, which takes place constantly from the whole surface 

 of our globe, and from the waters of the sea, lakes, and rivers ; 

 thus furnishing a constant moisture in our atmosphere, holding 

 therein, in solution, a number of foreign substances which plants 

 imbibe and eliminate for their own peculiar use ; and it is a 

 well ascertained fact that no electrical action takes place unless 

 accompanied with some chemical change. Now this constant 

 evaporation and the chemical change that is thus going on upon the 

 surface of the earth, in the respiration of animals and plants, and 

 the various cosmical phenomena of our globe, are supposed to be 

 some of the sources which give rise to the generation and frequent 

 changes of the electrical state and tension of our atmosphere. I 

 would just allude to a theory which has a certain reference to the 

 supposed connection between the amount of Ozone and the 

 electrical tension of the atmosphere. It is stated that the earth is 

 always charged with negative electricity, or that the earth is 

 negatively electrified, and that the vapours which rise from its 

 surface are, like itself, of a negative character ; but from a 

 constant law observed in electrical phenomena, named induction, 



