222 Sir Fredenclc Ahel [March 13, 



depots, where special arrangements were adopted to maintain the 

 stores uniformly at a very moderate average temperature, the loss of 

 petroleum sj^irit from leakage and evaporation was estimated, ten 

 years ago, to amount to about 18 per cent, of the total stored, while 

 the average loss from the same causes upon petroleum oil was about 

 9 per cent. By the introduction from time to time of improvements 

 of the arrangements, the loss of spirit by leakage and evaporation 

 has been very considerably reduced, amounting to less than 8 per 

 cent, in well-constructed stores, while at some petroleum stores, more 

 especially in Germany, the loss of oil from leakage is now said not to 

 exceed 1 per cent. 



As in the case of the loss of coal-laden ships by explosions on the 

 high seas, such loss has probably in many cases been due to the 

 development of gas from the cargo, and to its diffusion into the air of 

 parts of the ship more or less distant from the coal, producing an 

 explosive atmosi)here which might become ignited by the convey- 

 ance or existence of a light or fire, where its presence was not 

 deemed dangerous; so also it is not improbable that the supposed loss 

 by effects of weather, of missing petroleum-laden vessels, may have 

 occasionally arisen from fire caused in the first instance by the 

 diffusion of vapour, escaping from the cargo, through the air in 

 contiguous parts of the ship, and the accidental ignition of the 

 explosive atmosphere thus produced. 



The possibility of such disasters has been demonstrated by the 

 repeated occurrence of accidents of this class in ports or their 

 vicinity. A very alarming instance of the kind occurred in 1871 on 

 the Thames at Erith. Two brigantines had nearly completed the 

 discharge of their cargoes of petroleum spirit (" na2)htha "), when 

 another vessel, the Muth, from Nova Scotia, containing upwards of 

 2000 barrels of the same material, together with other inflammable 

 cargo, anchored alongside them. This ship had encountered very 

 severe weather, and it had been necessary to batten down the hatches ; 

 the cargo in the hold had consequently become enveloped in the 

 vapour which had escaj^ed from the casks. On the removal of the 

 hatches, an explosive mixture was speedily produced by access of 

 air, and, through some unexplained cause, became ignited shortly 

 after the vessel anchored. A violent explosion followed, and the vessel 

 was almost instantly in flames, the fire being rapidly communicated to 

 the other two ships, which were with difiiculty saved after sustaining 

 considerable injury, while the Ruth, in which the fire raged uncon- 

 trollably, was after a time towed to a spot where she could burn 

 herself out and sink, without damage to the other shipi^ing. Three 

 of the crew were seriously injured by the explosion, and the mate 

 was blown to some distance into the water. 



In June 1873 a vessel (the Maria Lee), laden with 300 barrels 

 of petroleum and other inflammable cargo, was destroyed by fire on 

 the Thames near the Purflcct powder magazines, consequent upon 



