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DECOMPOSITION OF WATER.

Let two fine gold wires be fixed in separate small glass tabes byfusion; and let the ends of these tubes be ground away till thevery section or extremity of each wire is laid bare: let the otherend of each tube be furnished with a larger wire connected witha metallic ball, which wire communicates with the gold wirewithin. These two tubes are then fixed by fusion in a largerglass tube, provided with a conical drawn aperture, throughwhich it can be filled with water, all but a small vacuity or bub-ble, and then sealed. The apparatus is then complete; and if astream of electricity or galvanism, be passed through it, the wateris decomposed. The apparatus will be more evident from thefollowing sketch:

The method of decomposing water by galvanism was discover-ed by Messrs. Nicholson and Carlisle, in the year 1801. Thisdiscovery will, in point of importance, for ever remain amongthe first discoveries that have been made in philosophical che-mistry. Nothing more is necessary for that purpose than to takea narrow glass tube 3 or 4 inches long; fit each end with a cork,penetrated by a piece of slender iron wire, and fill the tube withwater. Let the ends of the two wires be distant from eachother, about three-fourths of an inch ; and let the one be madeto communicate with the bottom of the galvanic pile, the otherwith the top. On making this communication, bubbles of airwill form, and ascend to the top of the tube ; the wire being ra-pidly oxidated. In this experiment, the water is decomposed;its oxigen unites with the iron, and its hidrogen appears in thestate of gas.

If this experiment be made with the substitution, for iron, ofsome metal that is not oxidated by water, as gold for example,we obtain a mixture of hidrogen and oxigen gases, as in the ex-periment of Messrs. Dieman and Van Troostwyk.