168 ANNUAL OF SCIENTIFIC DISCOVERY. 



suiruicntlv beneath the suvlacc to insure moisture in the di-yest 

 part of the season. If circumstances permit, it should connect 

 ■with a spring of water, a drain, or some other conducting 

 channel." 



Numerous instances of the ascending stroke have occurred, the 

 records of which are extant. It must be evident that a single rod, 

 extending above only one point of the building, will not properly 

 protect the structure to which it is applicul from one of these up- 

 ward strokes, neither is it cllieient against an oblique or divided 

 discharge. The whole building, top and sides, must be protected 

 by a continuous rod with numerous projecting points for receiving 

 and discharging the electric lluid. 



Passing the rod through glass insulators does not seem to be 

 always elfectual to pnjtect the building. The interposition of a 

 glass knob between the rod and the building, appears to be 

 preferable. In cases where the rod has passed tia-ough a hollow 

 cylinder of glass, it has l)e<Mi found that tlic glass would l)urst, 

 and the lluid enter the building by the iron staple which hekl the 

 glass ring. 



Some of the old-fashioned and erroneous notions entertained 

 and religiously believtMl by j)ersons in relation to the ellects of 

 liglitning, and particularly the means of protection, have been 

 exploded by the occurrences of this season. That feathers afford 

 no protection against electricit}' is i^roved I)y the case of a woman 

 in St. Louis, who was killed by a stroke of lightning while lying 

 on a featlier bed. An instance of one of three persons sitting 

 near a closed window being struck also dispels the illusion that 

 the interposition of window-glass is an effectual bar to the action 

 of the destructive element. 



The only elheient protection is that of a good i"od, properly put 

 up. The subject is too imjwrtant to be lightly })assed over ; and 

 it is no less important that the confidence of the purchaser should 

 not be betrayed, and life and property endangered, by accept- 

 mg an inelKeient conductor, or one improperly applied. 



Many buildings are now constructed, both in this city and in the 

 country, with metallic-covered roofs, and very few are erected 

 without metallic eaves, troughs, and conductors. In all such 

 cases, the efficiency of lightning pi'otectors is impaired by the pre- 

 ponderance of conducting surface on the roof and down the sides 

 of the buildiu":. This metallic covering?, and these rain-conduc- 

 tors, whether of tin, zinc, or lead, are better conductors of elec- 

 tricity than the building of stone, brick, or wood, and should be 

 utilized as a means of protection against lightning. For this pur- 

 pose, strips of iron, zinc, or copper, should connect the lower 

 extremities of the water-spouts with the damp earth, a well, or 

 a running stream of water, and the eaves-troughs should have a 

 connection Avith the metal roofing and with the vertical conduc- 

 tors. Water is a good conductor of electricity ; and when, in a 

 thunder storm, the rain is jjouring down the conduits of a build- 

 ing, their conducting properties are largely increased. Properly 

 connected, these useful appliances can be mad6 doubly valuable 

 as hai-mless conductors of electricity. 



