196 Proceedings of the Ohio Academy of Science 
We explain, for example, the origin, the progress and the 
ending of a thunderstorm when we classify the phenomena 
presented by it with other more familiar phenomena of vapor- 
ization and condensation. But primitive man explained the 
same thing, to his own satisfaction at least, when he classified 
it along with the well-known phenomena of human volition by 
constructing a theory of a great black dragon pierced by the 
unerring arrows of an heavenly archer. As late as 1600, a 
German writer would illustrate a thunderstorm destroying a 
crop of corn by the picture of a dragon devouring the produce 
of the field with his flaming tongue and iron teeth. But we 
of today no longer regard the thunderstorm as an object of 
terror or as an unfathomable mystery, but rather as a natural 
phenomenon of great economic and scientific interest, one in 
every way worthy of our best and most serious consideration. 
The physics and physical features of the thunderstorm are, 
we believe, fairly well understood. These have been ably and 
fully discussed by Professor Humphreys of the U. S$. Weather 
Bureau, whose teaching we follow very closely in this discussion. 
If the thunderstorm produced only lightning and thunder, it 
would be of only relative importance, but it may bring along 
a whole series of redoubtable phenomena, thus presenting 
problems of real practical importance—problems the magni- 
tude and importance of which are not always fully appreciated. 
2. Definition 
And now, first of all, let us ask and answer, if we can, this 
question: ‘‘ What is a thunderstorm?’ Ordinarily, for example, 
we think of a windstorm as a storm characterized by high and 
perhaps destructive winds; of a hailstorm as one characterized 
by the production of hail; of a snowstorm as one that produces 
snow; of a dust storm as one characterized by a great quantity 
of flying dust; and so, quite properly, we think of a thunder- 
storm as a storm characterized by thunder and lightning. This 
may not, I grant you, serve as a satisfactory definition, but it 
will, perhaps, be a sufficient answer for the time being to the 
question asked. 
It is not necessary in this presence, perhaps, to point out 
that the ‘‘snow,” the ‘‘wind,” the ‘‘hail,’’ and the ‘‘dust,’’ 
are in no sense the cause of the storm to which they give name. 
