VOL. LXVIII.] PHILOSOPHICAL TRANSACTIONS. 355 



bottom of wells; one of which should be dug for that purpose nearly in the 

 middle of each of the intervals between the magazines, deep enough to contain 

 at least 4 feet of water. The middle strip should be connected with the iron rod 

 over the door, hereafter to be mentioned. We also advise, that other high pointed 

 rods be erected ; I at each of the 4 corners, and one over each of the metal doors 

 in the middle of the sides; which latter should be bent, so as to avoid the doors, 

 in the same manner as those which are already placed on the outer side of the 

 outermost magazines. All which rods should be continued into the earth, and 

 be made to communicate with the bottom of the water of the nearest wells, by 

 means of leaden pipes, closely connected with these iron rods. Likewise, that 

 strips of lead be put on the copeing of the end walls, and be made to communi- 

 cate with the rods to be placed at the several corners as above directed. 



3. But that the greatest degree of security would be attained by covering the 

 whole roof, and the tops of the end walls of each of the 5 magazines, with lead; 

 erecting all the additional conducting rods above directed; and forming a com- 

 munication between the leaden covering of the roof, and the bottom of the wells 

 as beforementioned. 



As to the other buildings belonging to the magazines, we recommend: 1. 

 That a pointed rod, similar to the rest, be erected at each end of the proof-house, 

 and be united with the lead already there: also, that the lead on the roofs of the 

 two low buildings, destined for the reception of the empty powder casks, &c. 

 be connected with the wells by means of one strip of lead in the middle of each 

 building, of the same breadth as those abovementioned. 



■2. That a pointed rod of copper, about three quarters of an inch in diameter, 

 be erected on each of the 4 chimnies of the Board-house, reaching 5 feet above 

 them ; and be connected, by strips of lead, with the other lead on the roof of 

 the building. 



We also advise in general: 1. That the lead and rods on the several buildings, 

 be respectively connected with the nearest wells, by the shortest metallic com- 

 munication that can conveniently be formed ; in particular, that the two leaden 

 spouts of the Board-house, which do not reach the ground, but terminate in 

 cisterns, be connected, by strips of lead, with those spouts that already communicate 

 with water. 2. That the different pieces of which the iron rods may be com 

 posed, be strongly screwed together in close joints, having a thin plate of lead 

 between them, as directed by the first committee. 3. That these rods be firmly 

 fixed, and closely connected with the lead on the roofs. 4. That all the strips 

 and pieces of lead be well fastened and soldered together, so as to make a perfect 

 metallic communication with the bottom of the wells. 5. That the iron rods be 

 painted, except in those places where they are to be in contact with the lead; that 

 they be all 10 feet high; and that they be terminated with pieces of copper 18 



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