986 Wlarvels of the Universe 
(2) sheet lightning; (3) ball, or 
globular lightning. The first, or zig- 
zag lightning, is the most common 
form, but as has been shown from 
photographs, the discharge should 
more properly be described as 
branching or ramified in most 
cases. The line of least resist- 
ance is probably followed by the 
“current,” and the presence of 
obstacles, solid particles, or local 
electrification, etc., | sometimes 
makes a crooked path, though 
longer than the direct one, easier 
for it to follow. Of recent years 
remarkable instantaneous photo- 
graphs of lghtning have been 
taken by Dr. Lockyer and other 
observers. The flash itself never 
lasts longer than 55545, of a 
second (Thompson), but is some- 
times of an oscillatory character, 
being in more respects than one 
similar in nature to the discharge 
of a Leyden jar. The second 
form, sheet lightning, commonly 
seen at night times on the horizon 
SARECTS OF ILIGRTRNING, and without thunder following, is 
An oak-tree of large size whose trunk has been split to the base by a probably only the reflection on the 
lightning stroke. clouds of flashes taking place at 
Photo by] 
some other region. | When seen reflected from a storm too far away to produce audible thunder it 
is often known as “ summer lightning.” The third form, globular or ball lightning, is very rare. 
Here the discharge appears to take the form of balls of fire which move slowly along and then explode. 
It is probable that some cases of the appearance of such balls of fire are not really electrical 
phenomena, but meteoric masses from outer space rendered incandescent by passing through the 
atmosphere and finally bursting into fragments on reaching the ground or in the lower air, but since 
similar phenomena have been occasionally observed by Planté, Cavallo, and others in the discharge 
of electrical machines, there seems no reason to doubt that this kind of discharge occasionally occurs 
in Nature, though the accounts have perhaps been exaggerated. 
The physical effects of lightning, as is well known, are of a most potent character, often causing 
death to men and other animals, blasting trees, and more or less completely destroying lofty and 
unprotected buildings. M. Flammarion, in his interesting popular work, gives examples of some very 
remarkable and often erratic performances of this intense form of atmospheric electricity. Instances 
are on record of persons being struck by lightning but receiving no other injury than the destruction 
of part of their clothing, their bodies being uninjured ; whilst in other cases its effects have been posi- 
tively beneficial. An innkeeper at Remaines (France), who suffered severely from rheumatism, and 
was quite unable to walk without the help of a stick, was struck by lightning and rendered uncon- 
scious for a time. For some hours afterwards his sight was affected, but he ultimately recovered, 
and, strange to say, was completely cured, being able to do without his stick and to pursue his 
