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remainder of the crown developed only a small portion of the 
leaves in 1902, and has begun to give indications of approach- 
ing death, so that the removal of the tree will soon be necessary 
(see Fig. 22). 
During the same year a large specimen of American elm (U/mus 
Americana) near the present location of the landing stage of the 
elevated railway was wrecked by a discharge that killed the tree 
so completely that it was removed. A white oak (Quercus alba) 
on the ridge of the herbaceous plantation was also the object of 
a discharge that tore a wide strip of bark from the surface of the 
trunk for a distance of forty feet and then the spark appeared to 
be ‘diffused through several branches, some which were ruptured 
and killed. This tree appears to offer an example of discharge 
from the earth, although the evidence is not at all to be relied 
upon as conclusive. 
Another instance of lightning stroke is to be seen in a large 
chestnut (Castanea dentata) standing on the eastern slope of the 
main ridge in the hemlock reservation. A discharge took place 
through this tree in July, 1899, which tore loose the bark, grow- 
ing layer and sap wood in narrow strips, from the trunk and a 
main branch in a spiral band a foot in width. In June, 1902, 
the larger branches in the crown were found to be dead, and the 
bark and cambium layer on both sides of the bared strip were 
dead over a width of a foot or two. The survival of the tree is 
doubtful. 
An interesting example was found in a specimen of ash (Fraz- 
inus Americana) east of the Bronx River, near the road leading to 
the Bleeker street entrance. The only evidence of the discharge 
in this case consisted of a narrow band of ruptured bark and 
sap wood, beginning a few inches above the surface of the soil, 
and extending upward to a height of about eight feet. No in- 
jury to the branches could be seen. No noticeable effect was 
exerted upon the general vigor of the tree 
From the various investigations that have been made of the 
subject it has been found that the electrical conditions of the 
clouds and earth may change quickly from negative to positive 
during the course of a thunderstorm, and that the differences of 
