414 Mr. Snow Harris on the Electrical Discharge 
tion. “ It is said (observes Mr. Sturgeon) that the lightning 
rod passing through the Nelson Monument became so hot 
by lightning that it could not be touched by the hand by the 
Jirst iperson who visited it afterwards. Allowing a few minutes 
to have elapsed between the flash and the person entering 
the monument, the probability would be that the conductor 
had been made red-hot.” This is of the same character with 
all Mr. Sturgeon's data; it is generally surmise, the sho’is:) 
without the reality; it just amounts to nothing. 
45. I am aware that it has been also supposed that the great 
conductors of St. Paul's church were heated by lightning, 
but it is only a supposition. The conductors were not ex- 
amined before the lightning, which was said to have fallen on 
them, occurred, so that we cannot be certain that the observed 
appearances were not originally present after the forging of 
them ; it is besides very unlikely, that a stroke of lightning 
should have fallen on this building, capable of rendering bars 
of iron, six inches wide and one inch and a half thick, red- 
hot, without destroying the thin copper covering the ball and 
cross on the dome of the building, and without the crash of 
the thunder having been heard over the whole city, no men- 
tion of which is made ; when St. Bride's steeple was struck, 
the latter was peculiarly remarkable. 
46. There is another instance on record, of the effects of 
lightning on an iron rod, in Port Royal, Jamaica, mentioned in 
the Transactions of the Royal Society, the evidence of which 
seems very incomplete. Two men are said to have perished 
by lightning near a church wall : that is not improbable : but, 
on subsequently looking inside the wall, a bar of iron an inch 
thick, and a foot in length, was found in raan}^ places wasted 
away to the size of a fine wire. Now it does not appear that 
this bar was examined previously to the occurrence of the 
lightning ; hence we cannot infer that the wasting was pro- 
duced by the electric fluid; more especially as similar ap- 
pearances are not uncommon in bars of iron erected in church- 
yards in this country, and which have evidently resulted from 
oxidation and time. 
47. Seeing then how much evidence we have from actual 
experience of the protective effect of regular conductors of the 
Voorst kind, and their power of transmitting dense explosions 
of lightning, we may reasonably infer that a conductor of 
copper equal to a rod of an inch diameter, and extending the 
Voliole length of the mast^ would be proof against any discharge 
of lightning ever experienced, as, I think, is shown by the 
cases in which ships fitted with my conductors have been 
struck by shocks of lightning without damage. 
