J. Henry on the Construction of Lightning-rods. 345 
4th. It should be terminated above with a single point, the 
cone of which should not be too acute, and to eee it from 
the weather, as well as to prevent its being melted, should be 
th. The shorter and more direct the rod is in its course to 
the earth the better. Acute angles, made b bending the rod, 
and projecting points along its course, should be avoided. 
6th. It should be fastened to the house by iron eyes, and may 
be insulated by cylinders of glass. We do not think the lat- 
ter, however, of much importance, since they soon become wet 
by water, and, in case of a heavy discharge, are burst asunder. 
7th. The rod should be connected with the earth in the most 
a 
buried in the moist ground. Pit should, before it descends to 
the earth, be bent, so as to pass off nearly at right angles to the 
side of the house, and be buried in a trench, surrounded with 
powdered charcoal. a. a 
8th. The rod should be placed, in preference, on the west side 
of the house, in this latitude, and especially on the chimney 
from which a current of heated air ascends during the summer 
Season, 
9th. In case of a small house, a single rod may suffice, pro- 
vided its point be sufficiently high above the roof; the rule 
