this opportunity of publishing in the ‘Philosophical Transactions’ a detailed account of the effects of lightning upon St. Bride’s steeple, explaining the potency of conductors in the very action of the electric force. He showed how the lightning first struck the metallic weathercock at the top of the steeple, and ran down, without injuring anything, the large iron bars by which it was supported. At the bottom of the bars, the electric force shattered a number of huge stones into fragments, to make its way to some other pieces of iron, inserted into the walls to give them strength. So it went on till there were no more metals, when havoc and destruction became the greatest. Thus, as Dr. Watson conclusively proved, the beautiful steeple of St. Bride was wilfully made over to ruin for want of a few hundred yards of iron, or other metal, which would lead the electric force harmlessly from the weathercock on the summit into the earth. He finished by telling in the plainest terms, to all on whom devolved the duty of taking care of churches, that it was neglectful, even to criminality, not to protect them by conductors against the always imminent danger of being struck by lightning. The lay-sermon of Dr. Watson, deeply impressive by the power of the indisputable facts on which it was based, had a considerable effect in rousing public opinion, finding its way even into the dull ears of ‘such as commonly compose church vestries.’ Among the most important results was a step taken, after long and solemn deliberations, extending over several years, by the Dean and Chapter of St. Paul’s. They made an application to the Royal Society, asking for advice as to the best means of protecting the great cathedral, Sir Christopher Wren’s noblest creation, against the perils of lightning. The application was made on March 22, 1769, as recorded under that date in the ‘Gentleman’s Magazine.’ ‘A letter from the Dean and Chapter of St. Paul’s,’ it was stated, ‘was read at the Royal Society, requesting the direction of that learned body for the sudden effects of lightning. It was referred to a committee consisting of Dr. Franklyn (_sic_), Dr. Watson, Mr. Canton, Mr. Edward Delaval, and Mr. Wilson, who, after having examined the building, are to report their opinion.’ The committee thus nominated embraced all the most eminent men of the day who had studied the phenomena of electricity, and in the order in which they ranked. Next to the great discoverer of the lightning conductor himself, Dr. Watson could claim to stand; and next to him Mr. John Canton, a most painstaking and intelligent worker in the field, inventor of the pith-ball electrometer, and other instruments.