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Account of a simple Apparatus Jbr collecting the Gases evolved 

 from liquids submitted to Galvanic Action. By the Rev. Mr 

 A. Robertson jun. Inverkeithing. (Communicated by the 

 Author.) 



X HIS apparatus consists of a glass-tube, of any size, divided 

 into three parts A, B, C, (Plate I. Fig. 1.) by the two bend- 

 ings D, E. The upper end is closed, and the lower immersed 

 in the fluid contained in the bottle F. G, H, are platinum-wires 

 inserted through the tube near the bending D. 



To use it, it is to be held with the part of the tube marked 

 A, nearly perpendicular, the open end being upwards, and the 

 liquid, through which the galvanic electricity is to be transmit- 

 ted, is poured in till the tube be filled. A sHp of paper, a little 

 broader than the diameter of the tube, is now to be placed over 

 the orifice ; and being extended, on both sides, along the tube, is 

 to be held there, so that the whole may be inverted, without 

 spilling, into the bottle F, previously half filled with the same 

 fluid. The wires G, H, are then connected with the galvanic 

 poles ; and, when the experiment is finished, the gas evolved at 

 the wire G, will be collected in the part of the tube A, and that 

 from the wire H, at C, in the manner represented in the figure, 

 the displaced fluid descending into the bottle. 



The volumes of the gases may be ascertained by graduations on 

 the tube, or they may be separately transferred into small jars, 

 by the aid of a pneumatic trough ; the gas at C, ascending into 

 one jar, upon the tube being turned up, while the gas at A oc- 

 cupies the part of it on each side of the bend D ; and this, after- 

 wards, upon a proper inclination of the tube, also ascends into 

 another; so that each of them may be examined by itself. 

 Should it be wished to recombine them, it may be done without 

 removing them from the tube, but by holding it so that the gas 

 at C may rise to B, and join that in it, and then transmitting 

 the electric spark between the wires. 



The advantages of this apparatus, when water, or any other 

 fluid, not corrosive, is to be decomposed, consist in its simplicity 

 and cheapness, as, by the aid of a blowpipe, it may be made in 

 a few minutes from any piece of glass tube of a proper size ; and 

 it possesses also every convenience of those which are more com- 



