Polytechnic Association. 693 



always under the supervision of the engineer, the safety of steam 

 power would, in the charge of a careful and skillful engineer, be 

 assured, if there were nothing else than the steam, water and fire con- 

 cerned in its use. But there is great reason to believe, that in the 

 process of raising steam, an immense quantity of electricity is evolved. 

 Galvanic and magnetic electricity, and electricity produced by fric- 

 tion, are now known to be the same, and identical with that of the 

 clouds in summer. "When a current of electricity is made to pass 

 through a compound substance, its property is to decompose and sepa- 

 rate the compound into its constituent parts. It is thus that water 

 is decomposed by the galvanic battery, resulting in the production of 

 the two gases, oxygen and hydrogen, in the proportions in which they 

 combine to form that fluid. All atoms of matter are considered as 

 originally chargeable with either positive or negative electricity ; in 

 water hydrogen is the electro-positivej and oxygen the electro-nega- 

 tive element ; and as opposite electrical states exercise strong mutual 

 attractions, this attraction being greater than that which unites the 

 two elements, decomposition ensues. Recent experiments have 

 shown that the electricity which decomposes, and that which is 

 evolved by the decomposition of a certain quantity of matter, are 

 alike. In contemplating the facts pertaining to the most violent dis- 

 ruptions of steam boilers, the theory that best agrees with them, we 

 suppose to be that which ascribes them to explosive gases, and which 

 involves two conditions: 1. The production and accumulating of 

 such gases in the boiler. 2. The presence of an agent to explode 

 them. 



1. In regard to the first condition, it is suggested that the raising 

 of steam affords an unlimited supply of material for the production 

 of the gases demanded by tjie theory. Water is composed of two 

 gases, and is converted into steam by the motion of its particles 

 combined with the radiating heat of the furnace passing through the 

 lower part of the boiler to the surface, and rising thence enormously 

 expanded into the upper part above the water. Under all circum- 

 stances, when in motion it is a prolific source of electricity, which is 

 produced in immense quantities by evaporation passing with the 

 vapor into the higher regions of the atmosphere, where its agency is 

 manifested in the formation of clouds and most conspicuously in the 

 cumulus of the summer skies. The heat which increases evapora- 

 tion increases the quantity of electricity evolved, and also its intensity ; 

 which is evinced by the phenomenon of the thunder cloud. The 

 numerous discharges of electricity in that description of cloud are 



