501 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[December 23, 1872. 
black carbonaceous deposit is formed, and tbe gas is 
deprived of a part of its carbon. If, however, the gas 
be passed through more rapidly, no such deposition takes 
place, although the time of contact of the gas with the 
heated surface is still sufficient to effect the conversion 
of the carbon bisulphide into hydrogen sulphide. In the 
latter case it may be presumed that no change occurs 
in the illuminating power of the gas. But to establish 
a point which is of capital importance, some direct 
observations were made on the illuminating power of 
gas thus treated. It was found with gas passing at the 
rate of 5 cubic feet an hour through a half-inch iron 
tube, heated for a length of twelve inches, that, when 
the heat did not exceed low redness, no change was 
observable. When the heat was raised to bright red¬ 
ness, there was a perceptible increase in the illuminating 
power. 
If the process of heating coal gas, in order to remove 
the sulphur contained in it, should be employed on the 
manufacturing scale, the rate of transmission of the gas 
through the heating apparatus would necessarily be such 
as to render any deposition of carbon very unlikely. 
But even where such deposition takes place, it is not 
necessarily accompanied by a diminution of the illumi¬ 
nating power. 
An interesting experiment, from this point of view, 
is the decomposition of marsh gas by the electric spark. 
When a stream of sparks from a Ruhmkorff coil is 
transmitted between the ends of platinum wires through 
a small quantity of marsh gas enclosed in a glass tube 
over mercury, the gas gradually expands. In about 
ten minutes it is nearly doubled, and at the same time a 
black deposit appears on the tube, in the neighbourhood 
of the wires. Here the intense heat applied has effected 
an almost complete decomposition of the hydrocarbon 
into its elements. But at the same time there is found 
a small quantity of some more condensed hydrocarbon, 
probably acetylene. On expelling the gas through a 
jet attached to the upper end of the tube, and burning it, 
the flame is seen to be much more luminous than that of 
marsh gas itself. The fact of which this experiment gives 
a striking illustration is that the illuminating power of 
gas depends much more upon the nature of the hydro¬ 
carbons it contains, than upon the total amount of 
carbon. How great would be the gain to the manu¬ 
facturers of coal gas, if such an operation as this were 
possible on the large scale, by which the volume of gas 
is doubled and its illuminating power, at the same time, 
greatly increased ! 
As far as chemistry is concerned, the simple operation 
of heating gas appears to offer the means of a sufficiently 
perfect purification. The construction of a suitable 
system of iron pipes for heating the gas, and the best 
mode of obtaining and applying heat, is a problem for the 
engineer. On the scale on which gas is manufactured, 
all the apparatus for dealing with it must be of a mag¬ 
nitude to which it is difficult to pass, even in imagina¬ 
tion, from the small scale of laboratory experiments; 
but, otherwise, the problem does not appear to be one 
of any peculiar difficulty. It may perhaps be found pos¬ 
sible to employ some of the waste heat of the retort- 
house for this purpose, and thus to effect the required 
purification without much increasing the consumption of 
fuel. 
RESEARCHES UPON SANTONIN.* 
BY M. L. DE SAINT-MARTIN. 
Santonin is the active principle of Semen contra, and 
has been prepared for some years past, upon a large 
scale, for therapeutic use. The reactions of this prin¬ 
ciple have, however, as yet been little studied. It re- 
* Memoir read before the Academie des Sciences, Nov. 
lltb, 1872 (Comptes Rendus, lxxv. 1190). 
inained outside any methodic classification until Ber- 
thelot, in his Traits Elementaire de Chimie Organique, 
included it in the grand class of organic compounds 
which in 1860 he instituted under the name of phenols. 
The author, therefore, undertook an investigation in 
order to ascertain its chemical relations. The investiga¬ 
tion included its reactions with reducing, oxidizing and 
decomposing agents; but the present paper only deals 
with some reducing experiments. 
If santonin be really a phenol, its formula C 15 H 1S 0 3 
indicates that it should be possible by its methodical 
reduction to obtain— 
(1) A diatomic phenol (C 15 H 18 0 2 ) ; 
(2) A monatomic phenol (C 15 H 18 0); 
(3) A carbide of hydrogen (0 15 H 1S )- 
This last carbide would present the composition of a 
homologue of naphthalin, isomeric or identical with 
amy lnaphthalin. 
The author has succeeded in obtaining the monatomic 
phenol (C ]5 H ls O) ; and he hopes to obtain shortly the 
other terms of the series. 
The monatomic phenol, to which compound the author 
has given the name of santonol, was obtained by intro¬ 
ducing into a long green glass tube, between two plugs 
of asbestos, a mixture of one part of santonin and four 
parts of zinc in powder, and heating it over a gas stove, 
in a current of hydrogen. A thick yellowish-brown 
liquid condensed in the cool parts of the tube, which 
after a few days, was full of crystals. This crude pro¬ 
duct was neutral to litmus, insoluble in water, very so- 
luble in alcohol and ether; treated with solution of 
potash in suitable proportions it dissolved completely. 
An excess of potash separated, under an oily form, 
potassic santonalate. This compound, or an analogous 
body very rich in potash, was also precipitated as an 
oily liquid when the original solution was diluted with 
pure water. Treated with an acid it reproduced san¬ 
tonol. These properties, and various others undescribed, 
show that the product was constituted by a body analo¬ 
gous to the phenols. 
But the crude product of the reaction was not a pure 
substance. In fact, the crystals and the mother-liquor 
presented a different composition. The first answered 
nearly to the theoretical formula C 15 II 18 0, while the 
mother-liquor contained much less carbon, perhaps be¬ 
cause of the presence of the compound C, 5 H 13 0 2 , inter¬ 
mediate between santonol and santonin. The crude pro¬ 
duct was therefore redistilled, which operation was 
effected without difficulty at about the boiling-point of 
mercury. The distilled liquid still separated into two 
portions, the one crystallized, and the other liquid; 
these w r ere analysed separately, and found to be iso¬ 
meric. 
The crystallized santonol had the appearance of the 
stearin which separates in the fatty bodies. After being 
purified as much as possible by pressure, it acquires a 
tolerable degree of hardness. Its fusing-point was about 
135° C. It was insoluble in water, very soluble in al¬ 
cohol and ether. Sulphuric acid formed with it a com¬ 
pound sulpho-acid, [of which the salt of baryta w-as so¬ 
luble. Analysis gave— 
Found. 
Calculated. 
l 
I. 
~n? 
c . . . . 
. 83-9 
83-8 
84-1 
H. . . . 
. 8-8 
8-9 
8-4 
0 (difference) 
. 7-3 
7'3 
7-5 
100-0 
100-0 
100-0 
The liquid santonol was a very unstable substance, 
which turned brown under the influence of the air. 
Like its solid isomer, it was insoluble in w-ater and 
very soluble in alcohol and ether. Its properties are 
