188 
ME. G. GOEE ON HYDEOFLTTOEIC ACID. 
conduct, and with ten elements it conducted readily. No odour of ozone was evolved, 
and the platinum anode gradually acquired a thick red-brown crust. By employing 
forty Smee’s elements the conduction was copious; the anode rapidly corroded, and 
much finely divided platinum as a greyish-black powder collected in and beneath 
the paraffin cup ; this powder appeared to be due to detached particles of the red- 
brown crust becoming reduced by the diffused bubbles of free hydrogen from the 
cathode, or was composed of particles of metal mechanically detached from the anode 
by the current. Portions of the soft earthy crust were scraped off at intervals into a 
platinum dish upon a heated slab of iron ; it dried to a dark-brown earthy salt (doubt- 
less fluoride of platinum), which rapidly deliquesced in the air to a tenacious sticky 
mass, similar to damp fluoride of silver : the anhydrous platinum compound was perfectly 
insoluble in the acid, but formed a blood-red liquid (like a solution of tetrachloride of 
platinum) with cold water, and the dilute aqueous solution, when heated, became full of 
flocks by separation of an insoluble basic, salt. By far the greater portion of the pla- 
tinum compound detached itself from the anode and became reduced to the metallic 
state, and only a small amount was left upon the anode as a soluble salt. The whole of 
the powder in the paraffin cup was found by appropriate tests to be metallic platinum. 
With an anode of very close-grained gas-carbon and six Smee’s elements, conduction 
occurred freely, and in less than half an hour nearly half the thickness of the carbon rod 
was disintegrated and fell as a loose powder to the bottom of the vessel. Numerous 
attempts were made to electrolyze the acid with a charcoal anode ; fifteen different kinds 
of wood, including some of the densest kinds, were converted into charcoal by very 
gradual drying and equally gradual heating to full redness in a copper tube retort until 
all evolution of gas ceased. Some of the resulting rods were exceedingly hard and dense, 
and emitted a clear metallic ringing sound when struck ; the denser kinds, especially 
those free from cracks, conducted freely even with ten Smee’s elements. The best kinds 
were those made from kingwood, beech, ebony, lignum- vitse, and boxwood ; that from 
lignum-vitee was nearly as hard as baked earthenware *. On immersing either of the 
rods in the acid, even without passing an electric current, it soon began to crack and fly 
to pieces, and on passing the current the rods commenced breaking immediately, and in 
some instances with dangerous violence, projecting fragments to a considerable distance ; 
even the hardest and densest kinds of charcoal behaved thus and became brittle through- 
out the immersed parts ; the most resisting kind was that made from beechwood. The 
number of Smee’s elements employed varied from ten to fifty-six, and the kind of electro- 
lysis-cell used was that represented by figure 13 (see page 189). The cracking of the 
charcoal was attended by evolution of numerous bubbles of gas (probably air previously 
absorbed by the carbon) ; on this account, and also in consequence of the fume developed 
by the heat of conduction-resistance in the charcoal, it was difficult to ascertain if the anode 
evolved gas due to electrolysis ; nevertheless, with the aid of a strong light and watching 
* For the preparation of articles and vessels of charcoal for these experiments, see Philosophical Magazine, 
September 1868. 
