146 ON THE PROCESS FOR PREPARING JAMES’S POWDER. 
skittle-pot, its cover laid on, and the whole placed on a stand in the fire-grate, 
and lumps of coal are to be built round and above it in such a way as to permit 
a free current of air to pass through. The skittle-pot and its contents will thus 
be brought to a uniform bright red-heat, which may be maintained at that de¬ 
gree for about an hour, more or less, according to the quantity. The skittle-pot 
is then to be taken from the fire, and should the powder prove to be pure white, 
except perhaps a thin layer at the top, it only requires to be reduced to the 
finest powder in an earthen mortar, and sifted through a fine silk sieve. Should 
the powder not prove white, it may be returned to the skittle-pot, placed in the 
fire as before, and continued in a state of ignition for half an hour, accoiding to 
the judgment of the operator. 
In the first part of the process, the sulphuret of antimony is slowly decom¬ 
posed; its sulphur burns, and exhales in the state of sulphurous acid. I he 
antimony, now insulated, appears in small brilliant spiculse, which, as the heat 
increases, gradually disappear. In the second part of the process, when the 
roasted matter is heated in the skittle-pot, the antimony, while in the state of 
vapour, combines with oxygen, and is converted into protoxide, part of which 
crystallizes in the upper part of the skittle-pot, or escapes as a thick, white 
smoke. The heat increasing, the protoxide is converted into antimomate ot 
antimony, which remains mixed or combined with the phosphate of lime. 
If the heat be raised much above that of a good coal fire in a common grate, 
the mass will slightly cohere, and in some parts will become yellowish and 
vitreous. If the heat be still higher, as that of an air-furnace, the powder will 
change to an olive-brown mass as hard as stone. 
All the time the powder is in the skittle-pot and very hot, protoxide ot anti¬ 
mony is escaping or crystallizing on the cover, and hence the difference disco¬ 
verable by analysis, and by the medical effects of different parcels of James s 
powder. It therefore becomes an important and difficult question, what is t e 
criterion by which the completion of the process is to be judged? I know of no 
other than this, that when the powder is white it is fit for use: any greater or 
longer-continued heat I believe to be injurious. It may not always happen 
that the whole charge will prove white ; when it does not, the whitest parts are 
to be separated, and, if worth the trouble, the remainder may be slightly cal¬ 
cined again. But should the first charge, after being duly heated, prove dark- 
coloured throughout, it cannot be improved and may be rejected. > 
Before concluding this paper, I may mention some facts relative to James s 
powder which were communicattd to me a great many years ago by a very old 
gentleman who had been an apothecary in Dublin, Mr. William Speer, the 
clever inventor of a well-known hydrometer for ascertaining the strength ot ex¬ 
cisable spirituous liquors. It was as follows:— . T>1 
In 1758 Dr. Anthony Relhan, a Fellow of King and Queen s College ot Fhy- 
sicians in Ireland, practised in Dublin, and was one of the physicians of Mercer s 
Hospital. The Fellows refused to meet him on account of his employing 
James’s powder in his practice, although the decree against antimonials by the 
French College of Physicians had been long before repealed. In consequence, 
he wrote to Dr. James, who advised him to go to London to practise, which he 
did. Becoming intimate with Dr. James, the latter, during several interviews, 
communicated the process practically to linn, his patent-right paving expired. 
In 1760 Relhan returned to Dublin, and being acquainted with Mr. Ducros, 
an eminent apothecary, then residing in W illiam Street, he communicated t e 
process to him confidentially. Ducros prepared the powder in presence ot 
Relhan and it was repeatedly administered in Mercer’s Hospital and other 
places, with exactly the effects of James’s powder. Mr. Speer was apprentice 
to Mr Ducros, and on his death in 1768 succeeded to his business: the widow 
gave up to Mr. Speer a MS. book containing the account of the Pulvis Jacobi, 
