208 On sotiie anomalous cases of Electrical Decomposiiiov, 



The receiver was then exhausted, and the vapour which had 

 formed at the top of the tube soon dilated sufficiently to expose 

 the point and plate; the spark was then passed across the 

 vapour, and a permanent increase in volume of the vapour was 

 soon detected. The experiment was continued for a week, the 

 apparatus working five hours each day ; at the end of that time 

 much of the gas formed had escaped into the receiver, and on 

 letting in the air the water rose in the tube until a bubble of gas 

 of 0*03 c. i. remained in the top ; this was analysed, and proved 

 to be pure hydrogen. 



On the interior of the tube was a dark pulverulent deposit, 

 far too minute in quantity for analysis, but which had evidently 

 proceeded from the platinum. 



The only possible mode in which I can account for this expe- 

 riment is, that this deposit consisted of an oxide or peroxide of 

 platinum ; and to account for it thus, it must be assumed that 

 platinum will decompose water by abstracting its oxygen. 



12th. I have endeavoured, by working for a long time upon 

 a limited quantity of water very slightly acidulated with sul- 

 phuric acid, to detect some compound which might be formed 

 by the oxygen which disappeared. 



I placed in a small tube 0*15 c. i. of distilled water, touched 

 with a rod which had been smeared with sulphuric acid. I con- 

 tinued working on this for a fortnight, averaging five hours 

 a day ; and as the liquid diminished by evaporation, I added 

 distilled water which had been recently boiled. No change 

 could be detected in the liquid at the expiration of this period. 

 It gave an acid reaction with test-paper, precipitated chloride of 

 barium, and showed no bleaching properties, which I looked for 

 as a result of absorbed oxygen. 



I have used the expressions positive and negative for the ter- 

 minals of the secondary coil which bore this relation to each 

 other upon breaking contact of the primary coil, and as far as I 

 could ascertain by direct experiment, there was no spark or de- 

 composition on making contact ; but although from the time 

 which the magnetic coil takes to acquire its magnetism no spark 

 is visible with this apparatus on making contact, possibly some 

 slight decomposition might take place on making contact ; this, 

 however, though it is well to notice the point, is immaterial to 

 the consideration of the results detailed in this paper, as, if the 

 currents were in alternate directions, the proportions of the gases 

 would be equally exceptional and anomalous. 



I have made many variations of the above experiments, but it 

 would be tedious to detail them. The following are the general 

 results : — 



1st. With distilled water containing a small quantity of sul- 



