‘We also advise,’ he says in his report, ‘in consideration of the great length of the buildings, that two wells of the same depth with the others should be dug within twelve feet of the doors of the two outside magazines--that is to say, one of them on the north side of the north building, and the other on the south side of the south building, from the bottom of which wells similar conductors should be carried up.’ It is not on record whether these recommendations were adopted by the Government, but it seems likely that this was the case, as the fear of explosion of powder magazines through a stroke of lightning was very great at the time. Not long before, a magazine had been so destroyed at Brescia, in Italy, with the appalling result of a considerable part of the city being laid in ruins, burying many hundreds of persons. The destruction of the Brescia powder magazine, like all similar events, had, it is scarcely necessary to say, its due effect in spreading a desire for lightning conductors, fear doing what was not effected by foresight. Whether or not the English Government made the wells recommended by Franklin for the Purfleet powder magazine, it is certain that the sound advice given was not largely followed. On the contrary, there grew a generally prevailing laxity in regard to the indispensableness of a good underground connection, which led to numerous accidents. They were seldom, however, ascribed to the right cause, others being sought instead--such as particular forms of conductors and the insufficient length of those phantoms called ‘reception-rods,’ which, as many thought, could never be made high enough, in order to ‘draw the electric fluid’ from the clouds. Height was sought where nothing but depth was required, and the same unsightly rods, towering high above buildings, would have very effectually carried off the electric forces if brought from the top to the bottom of the conductor, being taken out of the air and stuck into the earth. Still, there were not wanting philosophical minds impressed with the truth that no lightning conductor can discharge its functions unless rooted in moisture, and who not only knew it, but did their best to spread this knowledge in all directions. One of these philosophers, a singular character in his way, was a German clergyman, the Rev. Dr. Hemmer, who lived at Mannheim, on the Rhine, at the end of the last century. Taking the deepest interest in Franklin’s great discovery, he made many experiments with lightning conductors, which brought him to the conviction that the electric force, in its chief tendency, seeks the mass of water on the globe, and that where this is not on the surface, it must be guided to it to become harmless. Consequently, he recommended to sink the conductor invariably deep into the ground, so as to reach water, and to subordinate everything else to this prime necessity. To make the use of lightning conductors as general as possible, Dr.