Royal Society of Edinburgh. 157 
In such a case, though, it may be suggested, that the long hori- 
zontal wire extending through a length of 4000 feet between 
the Nelson Monument and the Castle for the service of the time- 
gun, should have been most abundantly charged by induction. 
That is true; and there is little doubt but that the said wire was 
The hole at “A,” as it appears on the under surface of the lead ; 
carefully drawn full size by Mr J. M. Corner, wood-engraver. 
copiously filled, and might have produced dangerous effects, had 
it not been furnished at either end with large copper plates in 
close proximity to many pronged conductors ending in wet earth, 
which led away innocuously the greater part of the charge. Enough 
however still remained to do some singular damage to the elec- 
trically controlled clocks at either end of the line. Thus, the 
members of one of the bundles of permanent magnets, near the 
pendulum-bob of the Castle clock, had their poles changed and 
their new attraction made rather stronger than their old; the 
members of a similar bundle in the Observatory window-clock 
had their poles partially changed; and in the interior of the 
Normal Mean Time clock one of the gold contact points was 
partially fused, and spattered on its steel spring, which was blued 
at that part as though by heat. 
The gold contact point thus treated, it will be understood, was 
