In March 1769, the Dean and Chapter of St. Paul’s addressed a letter
to the Royal Society, requesting their opinion as to the best and most
effectual method of fixing electrical conductors on the cathedral. A
committee was formed for the purpose, and Benjamin Franklin was one of
the members; their report was made, and the conductors were fixed as
follows:
The seven iron scrolls supporting the ball and cross are connected
with other rods (used merely as conductors), which unite them
with several large bars, descending obliquely to the stone-work
of the lantern, and connected by an iron ring with four other
iron bars to the lead covering of the great cupola, a distance
of forty-eight feet; thence the communication is continued by
the rain-water pipes to the lead-covered roof, and thence by lead
water-pipes which pass into the earth; thus completing the entire
communication from the cross to the ground, partly through iron,
and partly through lead. On the clock-tower a bar of iron connects
the pine-apple at the top with the iron staircase, and thence with
the lead on the roof of the church. The bell-tower is similarly
protected. By these means the metal used in the building is made
available as conductors; the metal employed merely for that purpose
being exceedingly small in quantity.--_Curiosities of London._