114 
charge from the clouds to be negative. Subsequent experiments 
showed that while in general the charge from the clouds is 
negative, it is sometimes positive. 
In 1749, Franklin applied his knowledge of the power of points 
to the practical protection of buildings. Hesays: ‘‘If those things 
are so [z. ¢., ‘if the fire of electricity and that of lightning be the 
same’] may not the knowledge of this power of points be of use 
to mankind in preserving houses, churches, ships, etc., from the 
stroke of lightning by directing us to fix on the highest points of 
those edifices upright rods of iron, made sharp as a needle, and 
gilt to prevent rusting, and from the foot of those rods a wire 
down the outside of the building into the ground, or down round 
one of the shrouds of a ship and down her side till it reaches the 
water? Would not these pointed rods probably draw the electrical 
fire silently out of a cloud before it came nigh enough to strike, 
and thereby secure us from that most sudden and terrible 
mischief ?”’ 
In 1753, Franklin formally recommended that pointed rods be 
placed on buildings to prevent their being struck by lightning. 
But the suggestion does not seem to have come very rapidly into 
favor, since in a subsequent letter to Kinnersley, written from 
London, in 1762, Franklin says: ‘* You seem to think highly 
of the importance of this discovery, as do many others on our 
side of the water. Here it is very little regarded; so little that 
though it is now seven or eight years since it was made public, I have 
not heard of a single house as yet attempted to be secured by it.’’* 
In 1777, at a meeting of the Royal Society Wilson protested 
against the pointed conductors of Franklin, and endeavored to 
prove the superior advantages of knobs to points, and the greater 
safety to be derived from blunt as compared with sharp lightning 
conductors. His experiments attracted considerable attention and 
evoked sharp discussion ; and during this discussion ‘‘ the pointed 
lightning conductors were taken down from the queen’s palace.’’ f 
They were never replaced, notwithstanding the condemnation of the 
pretended improvement by the Royal Society in their reports in favor 
of pointed conductors, and their being consequently generally em- 
ployed for the protection of the powder magazines throughout the 
country. On being urged to reply to Wilson’s assertions, Franklin 
* New Experiments and Observations on Electricity, p. 416. 
+ Memoirs, Vol. ii, p. 79 
