40 REPORT — 1853. 



If, instead of allowing the gases to escape from each, such vessels are closed, a very 

 considerable amount of pressure is obtained. The late Professor Daniel many years 

 since experimented with a closed glass vessel, as did Dr. Leeson, but in each instance, 

 before any great pressure was obtained, the vessels broke with very considerable vio- 

 lence. 



Will Faraday's law hold good under extreme pressure ? Is there any point at 

 which the pressure will recompose the hydrogen and oxygen evolved by the electrolysis 

 of water ? Is there any point at which water under such pressure will cease to be 

 electrolysed? and will it, under such circumstances, continue a conductor? 



All these questions appear to me to be well worthy of examination ; and although 

 the experiments I have hitherto made are far from being conclusive, they prove that, 

 as far as I have been able to obtain apparatus of sufficient strengtli to withstand the 

 pressure, water does continue to be electrolysed according to the law of Faraday, and 

 that the gases under such a condition do not recombine. 



My first experiments were made in glass tubes ; in each end I inserted a platinum 

 wire, and filling the tube with diluted water slightly acidulated with pure sulphuric 

 acid, the ends of the tubes were closed by mechanical pressure. A voltameter con- 

 structed on the principle of Mr. Martyn Roberts, and a galvanometer were introduced 

 in the circuit of a battery consisting of 10 small cells of Grove's. Many experiments 

 were made with such and similar apparatus, but all the tubes brokelong before any great 

 amount of pressiu'e had been obtained. 



Finding it was useless to expect any results from using glass, I then attempted the 

 experiment with metal. 



Into a copper tube, a hole of J inch diameter, and about f inch long, was bored. 

 This v?as insulated by being placed on a piece of dry leather, a platinum wire attached 

 to a platinum plate being introduced into the copper vessel, which had been previously 

 filled with diluted water slightly acidulated. 



The air from the water had been carefully extracted by boiling under a good 

 air-pump; as before, I used 10 cells of a small Grove's battery, a galvanometer and 

 a Roberts's voltameter being introduced iu the circuit, and the circuit completed by 

 making the copper vessel negative and the platinum wire positive ; when 10*5 of the 

 mixed gases had been evolved in the voltameter, the tube burst with considerable vio- 

 lence ; taking the capacity of the tube at ^^ths of a cubic inch, the pressure thus ob- 

 tained was about 525 atmospheres. 



Since that period I have had an apparatus constructed by which I can collect the 

 amount of gas from the vessel in which it is confined, for unless some mode could be 

 devised by which this could be effected, no satisfactory result could be expected. 



In all my previous experiments I calculated on being able to collect the gases by 

 opening the vessels under water, but finding it indispensable that the apparatus should 

 be much stronger, and consequently larger, I was compelled to use other means. 



The apparatus in which my experiments have since been conducted, were constructed 

 entirely of platinum encased in solid pieces of gun-metal about 6 inches in diameter. 



The first had a capacity of -j^ths of a cubic inch. In one experiment, after 103 

 cubic inches of tlie gases had been evolved, a loud explosion took place ; the concus- 

 sion was so great as to extinguish the two gas lamps in my laboratory ; my assistant, 

 who was observing the apparatus, saw a sudden appearance of light as of a flame 

 round the upper part of the apparatus as the gas escaped, the leather washer driven 

 out in perfect shreds, and from the upper valves being perfectly dry, no gas had 

 escaped previous to the explosion. 



On testing the platinum vessel by nitric acid, I found it had burst, the acid acting 

 in the copper through the platinum ; this fracture must have taken place at the time 

 of the explosion, as the wire attached to the upper part, which was the negative elec- 

 trode, would otherwise have had a coating of copper, whereas it was perfectly clean. 



The above experiment will give a pressure of 171 atmospheres. 



Another apparatus was then constructed, having a capacity of -j^jths of a cubic inch. 



I will not occupy the time with any detailed account of experiments which have now 

 occupied me some years, as after an accident I have often been detained for months 

 before I could obtain another apparatus, but I will briefly describe two which may be 

 interesting to this Section of the Association. 



In the first, after 110 inches had been evolved in the voltameter, I opened the 

 valve of the apparatus, and collected the same quantUy which had been under pres- 



