Mr Kemp on a New Kind of Galvanic Trmigh. 77 



manner as in the one immediately preceding ; instead of arcs of copper-wire, 

 //» I'^ig- 1- I*late III. are syphons of glass which connect the spaces on each 

 side of the higher glass divisions, being the positive and negative i)lates ; they 

 are inserted into the bottom of the trough by cement, and open into the spaces, 



that part of the tube which opens into the trough, and for about one inch 



downward, being half an inch in bore, the rest of it being only about one- 

 eighth part of an inch. 



In charging this battery, a quantity of pure mercury is to be poured into 

 the first space, sufficient to cover the bottom of it, and also to fill the whole 

 syphon. When the mercury appears at the surface in the opposite limb, a cork 

 is to be inserted, to prevent the mercury from filling the space it opens into. 

 In the same manner we proceed to fill the whole of the syphons and alternate 

 spaces. The remaining cells are then to be filled with the amalgam of mer- 

 cury and zinc, and the corks removed. The two liquid metals will now be in 

 complete contact, by means of the syphons of mercury. If water and acid be 

 now poured over the surface of the metals until it rises nearly to the top of 

 the higher glass divisions, a communication will be formed throughout the 

 series, and we obtain a galvanic arrangement completely liquid, without a 

 solid metal being either used for generating or transmitting the fluid. 



The syphons, in this arrangement, might have occupied the same place as 

 the arcs of wire did in the former one, by passing over the higher glass divi- 

 sions ; but the difficulty of filling them, and also of preventing the hydrogen 

 rising in them and breaking the communication, induced me to have recourse 

 to the plan I have adopted, in having them placed under the trough. If, in 

 the present instance, the communication should be broken by the acid and 

 water getting into the smaller part of the syphons, this can be easily expelled, 

 by applying the flame of a candle to it, and the communication again instant- 

 ly restored. 



Two troughs of this kind being placed parallel to, and at the distance of 

 half an inch from, each other. Fig. 2. Plate III., are connected by a glass syphon, 

 passing from the one to the other, so as to form a continuous series ; the other 

 two ends will be the positive and negative poles. 



I shall merely notice one experiment which I performed by this arrange- 

 ment, viz. the decomposition of water : For this purpose I employed a small 

 bent tube. Fig. 3. Plate III. in the form of a syphon, having a ball below in the 

 bent part of it, and the ends of the limb slightly turned up, to prevent the es- 

 cape of the liquid. This being filled with water, the limbs are to be plunged into 

 a vessel containing mercury. Upon applying heat to the ball, a quantity of 

 the water will be expelled, which will be immediately replaced by the mercury 

 rising in both limbs of the tube, — the mercury should rise nearly to the bend 

 of the tube. The syphon in this state is to be removed, and made to form 

 the circuit in this arrangement. The hydrogen is immediately evolved, and 

 rises into the ball, while an oxide appears on the surface of the mercury. 



In this experiment is exhibited the decomposition of water, without the use 

 of any solid metal, either for generating or transmitting the fluid*. 



• These instruments are to be seen at No. & CoUege Street, Edinburgh. Mr Kemp, we under- 

 ataad. propose* manufacturing a rtock of them for tale.— Edit. 



