ON A TEST FOR METHYLIC ALCOHOL. 215 
clear filtrate with chlorine water and ether. (Vide Wood and Bache’s U. S* 
Dispensatory.) 
Moisture. —Heat at 250° till the residue ceases to lose weight. 
Iodide. —Precipitate the chloride and iodide as silver salts, and subtract from 
the total the chloride found. 
[N.B.—When a sample contains iodate and carbonate, the latter may be esti¬ 
mated as carbonate of lime by the usual methods ; and when the iodide is esti¬ 
mated, the resulting iodide of silver contains the iodine due to the decomposition, 
of the iodate, by the addition in the first instance of NO-. 
See also the 1 Pharmaceutical Journal,’ April, 1864, under the 4 Transactions 
of the Leeds Chemists’ Association.] 
The Table speaks for itself in regard to the results to be deduced from it. 
That old and inconvenient impurity, iodate of potash, is fast disappearing, 
and here it is that the English samples claim the preferences; still, the quantity 
is so small, that had the calcination been carried a little further, none of it 
would have remained undecomposed. Bromide of potassium has been men¬ 
tioned by various writers (see 4 Lancet,’February 20th, on the British Phar¬ 
macopoeia processes) as a common impurity. However, not even traces have 
been found. 
I have noticed in proceeding with the analyses that those samples known to 
have been crystallized from spirit contain more moisture than the others (Nos. 
XIV. and XV.). No. III. is an exceptional instance, through having been 
transmitted by post, and is only inserted for the sake of the other constituents. 
It shoukl also be stated that the samples were of the best quality offered by 
the various makers, though in several instances there were good reasons for sus¬ 
pecting them. 
The general conclusion to be drawn is that iodide of potassium, as at present 
offered for sale, is practically pure. 
ON A TEST FOB METHYLIC ALCOHOL WPIEN MIXED WITH 
ETHYLIC ALCOHOL, WITH BEMABKS UPON METHYLATED 
SPIBIT. 
BY MR. JOHN TUCK. 
(Read at the Bath Meeting of the British Bharmaceutical Conference , Sept. 1864.) 
Methylated spirit, as is well known, is a mixture of ten per cent, ordinary 
wood naphtha with ninety per cent, of spirit of wine. This mixture is allowed 
to enter commerce duty -free, and has proved a great boon to the arts and manu¬ 
factures of this country generally. I need only refer to its great use in the beau¬ 
tiful coal-tar dyes, varnishes, polishes, fulminating mercury, spirit of nitre, 
chloroform, ether, the alkaloids, and resinous principles of drugs, and its applica¬ 
tion as a cleanly and cheap source of heat in the laboratory, and when mixed 
with hydrogen as a source of light as well, not to mention numberless other 
uses to which it has been applied, to show it to be an article of the greatest im¬ 
portance. 
From the nature of its manufacture, wood naphtha, or methylic alcohol, will 
always be a variable mixture; it is never produced by any kind of fermentation, 
and is met with in the liquid products of the destructive distillation of wood, 
and it is obvious that these products will be materially affected according to the 
nature of the wood, and the greater or lesser degree of heat employed in its de¬ 
structive distillation. These condensed products, consisting of naphtha, acetic 
acid, acetone, acetate of methyl, acetate of ammonia, oily hydrocarbons, as 
benzole, toluole, xylole, cymole, and other compounds, such as picamar, eupion, 
capnomor, pyroxanthin, and creasote, as well as tarry and resinous matters, after 
