WATER-PIPES ON A DISCHARGE OF LIGHTNING. 117 



water-pipes within a building. I have therefore recom- 

 mended that in all cases where lightning-conductors are 

 attached to buildings fitted up with gas- and water-pipes, 

 the lower extremity o£ the lightning-conductor should be 

 bound in good metallic contact with one or other of such 

 pipes outside the building. By attending to this precaution 

 the disruptive discharge between the lightning-conductor 

 and the gas- and water-pipes is prevented, and the fusible 

 metal pipes in the interior of the building are placed out of 

 the influence of the lightning discharge. 



Objections have been raised by some corporations to the 

 establishment of metallic connexion between lightning- 

 conductors and gas-mainSj on the ground that damage 

 might arise from ignition and explosion. These objections 

 are most irrational, as gas will not ignite and explode 

 unless mixed with atmospheric air, and the passage of 

 lightning along continuous metallic conductors will not 

 ignite gas even when mixed with air. Moreover, in every 

 case of the ignition of gas by lightning, the discharge is 

 actually transmitted along the mains^ such objections 

 notwithstanding. A grave responsibility therefore rests 

 upon those who, after introducing a source of danger into 

 a building, raise obstacles to the adoption of measures for 

 averting this danger. 



