30 KANSAS CITY REVIEW OF SCIENCE. 
‘ship in 1749. His attention was called to a ball of blue fire, as big as a millstone, 
which was rolling along the surface of the water three miles away. Very soon it 
reached to within forty yards of the main chains, when it rose perpendicularly 
with a fearful explosion, and shattered the maintopmast to pieces. Still another 
“ instance of a sort of globular lightning was furnished by the great storm in Brit- 
tany in 1718, during which twenty-four church towers were damaged. Three 
globes of fire, each more than a yard in apparent diameter, fell at once upon a 
spire near Brest, destroying the church completely. 
I need say little of the nature of lightning, since everybody is familiar with 
the story of Franklin and his kite. Every child knows that the flash is produced 
by the discharge of electricity accumulated in the clouds. But atmospheric elec- 
tricity may become manifested in either of two different ways. When lightning 
is seen we observe what is called a ‘‘ disruptive discharge;” while in the phenom- 
enon best known as ‘‘St. Elmo’s Fire” a ‘‘ glow discharge” takes place. The 
latter is harmless, and rather rare. Occasionally its peculiar brushes or balls of fire 
tip the ends of masts and spars during storms at sea, as many as thirty of these 
flames having been seen on one vessel at the same time. Once in a while, too, 
it is produced on land. ‘Troops of soldiers have been terrified at finding the tips 
of their lances or bayonets adorned with mysterious fires. Similar flames have 
decorated the hair and the finger ends of travelers caught in a storm above the 
snow line in the Alps. A wagon loaded with straw has been so electrified that 
every straw seemed to be in a light blaze. And at Plauzet in France the three 
points of the cross upon the church were seen surrounded by flame during every 
thunder-shower for twenty-seven consecutive years. But with these glow dis- 
charges we have little to do. The disruptive discharge concerns us, especially 
with regard to its effects. ( 
These effects may be conveniently studied under two heads; first, the effect 
of the lightning upon the air through which it passes; secondly, its effect upon 
the object struck. The first of these heads needs to occupy our attention but very 
briefly. Often after a thunderstorm, especially near articles which have received 
the flash, a peculiar odor is perceived. This odor is commonly described as a 
‘“ brimstone smell,” and, taken in connection with the bluish, sulphurous color 
of the spark, has led people to imagine the actual presence of sulphur in the 
storm. But the odor really belongs to ozone, a modification of oxygen produced 
by the passage of an -electric spark through that gas. Three volumes of oxygen 
have been condensed to two, and the product has the pungent perfume so well 
known. 
But it is when we come to consider the effects produced by lightning upon 
the objects which it strikes that we reach the most interesting ground. Some of 
these effects have already been described or hinted at, and most of them are so 
familiar to everyone that they seem hardly to need extended notice. Yet the 
material is so abundant and so varied that it becomes easy to select many interest- 
ing illustrations of our subject. Take for instance the formation of ‘‘fulgurites” 
