1883.] Origin of Lightning Rods . 531 
enough to strike, and thereby secure us from that most 
sudden and terrible mischief? ” 
Dr. Priestley quotes another paper by Franklin, written 
on November 7th, 1749, or probably about the same time as 
the memorandum last mentioned was written ; but this 
second paper does not appear in the third edition of the 
Letters from which we have been making extracts. After 
enumerating all the known points of resemblance between 
lightning and the electric spark, Franklin says, in this latter 
paper, “ The eleCtric fluid is attracted by points. We do 
not know whether this property be in lightning, but since 
they agree in all the particulars in which we can already 
compare them it is not improbable that they agree like- 
wise in this. Let the experiment be made.” — (Hist. BleCt., 
i 6 5 *) 
In these two extracts, and especially in the first memo- 
randum, headed “ Properties and Effects of the Electrical 
Matter,” the invention of the lightning rod is clearly enun- 
ciated. They are written some two years after the discovery 
of the power of points was published ; but it is evident that 
the invention of the rod was, in Franklin’s mind, a corollary 
of the knowledge of this power. We see that all this time 
not one word is mentioned of any conducting power that such 
instruments might be supposed to have over the lightning 
or over the electrical discharge. In allusion to the invention 
of rods, and to the analogy that had previously been observed 
between lightning and the eleCtric spark, Priestley says 
“ It was Dr. Franklin who first proposed a method of veri- 
fying this hypothesis, entertaining the bold thought, as the 
Abbe Nollet expresses it, of bringing lightning from the 
heavens ; of thinking that pointed iron rods, fixed in the 
air, when the atmosphere was loaded with lightning, might 
draw from it the matter of the thunderbolt, and discharge it 
without noise or danger into the immense body of the earth, 
where it would remain as it were absorbed.” — (Hist. EleCt., 
164.) Here, again, there is no reference to the conduction 
theory,- — i.e., to the idea of conducting the discharge away 
from the building by means of the metallic stalk of the rod 
after the stroke or explosion has occurred. 
Franklin’s third letter in the literary chain showing the 
development of the lightning rod is dated October 19th, 
1752, or nearly three years after the vital “ Properties and 
EffeCts ” memorandum. He gives an account in this third 
letter of an experiment made at Philadelphia (he does not 
say by whom) with a kite, consisting of a cross made of 
light strips of cedar with a silk handkerchief extended over 
