June 28, 1873.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
1043 
titles :—1. “ Researches on the Action of the Copper-Zinc 
Couple on Organic Bodies.” 3. “ On Normal and Iso- 
Propyl Iodides,” by J. H. Gladstone, F.R.S., and A Tribe, 
being a continuation, in the Propyl Series, of the authors 
previous researches. 2. On the Influence of Pressure on 
Fermentation, Part II : The Influence of Reduced 
Atmospheric Pressure on the Alcoholic Fermentation, by 
Horace T. Brown ; in which he stated that, under dimin¬ 
ished pressure, the progress of alcoholic fermentation 
is retarded in a remarkable way. 3. “ On Cymene from 
different Sources optically considered,” by J. H. Gladstone, 
F.R.S. 4. “ Note on the Action of Bromine on Alizar¬ 
ine,” by W. H. Perkin, F.R.S. This reaction gives 
rise to bromalizarine , an orange coloured crystalline 
substance, possessing feebler dying properties than pure 
alizarine, the colouring principle of madder. 5. “ On 
some Oxidation and Decomposition Products of Morphine 
Derivatives,” by G. L. Mayer and C. R. A. Wright, D. Sc. 
6. On the Decomposition of Tricalcic Phosphate by 
Water,” by R. Warington. 7. “ Communications from the 
Laboratory of the London Institution, No. XII: On the 
Nature and on some Derivatives of Coal-tar Cresol,’ by Dr. 
H. E. Armstrong and C. L. Field. 8. “ On a new Tel¬ 
lurium Mineral, with Notes on a Systematic Mineralogical 
Nomenclature,” by J. B. Hannay. 9. “ Note on^the 
Relation among the Atomic Weights,” by J. A. R. New- 
lands. The President finally adjourned the meeting until 
after the recess, congratulating the members on the flourish¬ 
ing state of the Society and on the number and importance 
of the papers that had been read during the session. 
SOCIETY OF ARTS. 
Recent Processes for the Manufacture of Gas 
for Illuminating Purposes.* 
BY T. WILLS, F.C.S. 
{Concluded from p. 1022.) 
With regard to these “ air gases,” all that remains is to 
state wherein the various plans differ in their mode of 
carburetting the air. The first of these recent schemes 
purposes to drive minute streams of air through a layer of 
spirit of a specific gravity of 0'670—this is accomplished 
by forcing air under pressure through a small tank of the 
liquid, having a false bottom of wire gauze; the passage 
of the air through the gauze divides it into innumerable 
fine streams, and causes it to come into close contact with 
the liquid material. The air, as it issues from the top of 
the tank, will thus be saturated with the hydrocarbon 
vapour. The depth of liquid through which the air passes 
is maintained constant by means of a somewhat ingenious 
float. It is further proposed, in this patent, to dissolve in 
the spirit a quantity of some more highly-condensed solid 
hydrocarbon ; but it is open to very considerable doubt 
whether the effect of such addition could be very percep¬ 
tible. . . .. . ... 
The illuminating power of this gas is very high, as high 
indeed as 30 candles, although this statement requires a 
slight qualification, as the lighting power of the flame is 
not expressed by it, but only the fact that if it were pos¬ 
sible (which it is not) to bum the gas at the rate required 
by the photometric test, viz., five cubic feet per hour, this 
illuminating power would be obtained, it being a fact that 
a very much smaller amount of air-gas can be burned 
from the ordinary li London argand burner, or fiom a 
batswing, to obtain the same size of flame than in the case 
of coal-gas ; this effect is no doubt due to the greater den¬ 
sity of “ air-gas.” It may be mentioned here that these 
air-gases do not burn at all well under pressure, and 
hence are only suited to burners which afford exceedingly 
free passage to the issuing gas, such as argands, there 
being a tendency with burners of the batswing and fish¬ 
tail class for the air and vapour to separate, possibly ex¬ 
plainable by the more rapid transpiration of the lighter 
* Read Wednesday, May 21, 1873. 
substance through a narrow opening. The gas produced 
by this particular scheme possesses, as might be expected, 
a very fair degree of permanency at ordinary tempera¬ 
tures, and is capable of transmission through compara¬ 
tively long lengths of pipe with little deterioration in 
quality. As an experimental trial, one side of the nave of 
the Crystal Palace has been recently lighted in this man¬ 
ner, with what success the public journals have testified, 
the spirit used for this purpose having a somewhat lower 
specific gravity than that mentioned in the patent. It is 
further stated that one gallon of oil will carburet 800 
cubic feet of air, and the cost of this gallon of oil to be 
two shillings. 
A second plan for obtaining the same result is a modifi¬ 
cation of the above, the special features of which are, in 
the first place, the required current of air being main¬ 
tained by clockwork, and, secondly, the substitution of a 
considerable length of cotton-wool or other absorbent sub¬ 
stance, kept saturated with the liquid hydrocarbon, in the 
place of bubbling the air directly through the liquid. The 
spirit used and the results obtained are very much the 
same as in the former case. This scheme also is being 
illustrated upon a somewhat extended scale, the small 
town of Great Marlow being at present illuminated by 
its means. 
Perhaps this latter has one slight advantage over the 
former, inasmuch as the bubbling of air through a volatile 
spirit will promote its evaporation, to such an extent that 
the temperature of the liquid will be reduced exceedingly 
low, in some cases as low as the freezing-point, and conse¬ 
quently the temperature of the air will be very consi¬ 
derably reduced at the same time. Now any unnecessary 
reduction of temperature, either of liquid or air, should be 
carefully avoided, in order to keep in solution as much 
vapour as possible. 
Yet a third plan has received some attention which 
possesses at least the advantage of simplicity, and this 
consists in using an ordinary gas-holder, with its tank, as 
a gas generator, to the exclusion of other apparatus. 
At the crown of this gas-holder is placed a valve, opening 
with ease inward, but closing the moment any pressure is 
applied to the holder. Underneath this valve are placed 
trays containing a shallow layer of a spirit, if anything, of 
somewhat lighter specific gravity than that used in other 
cases. As the gas-holder is mechanically raised, the en¬ 
tering air passes over the surface of the volatile hydro¬ 
carbon, becoming in this manner sufficiently charged to be 
immediately used as an illuminating gas, which may be 
consumed through most ordinary fittings. The illuminat¬ 
ing power of the flame, expressed in the same manner as 
before, is from thirty to thirty-three candles. The spirit 
_of which one gallon, it is believed, will carburet 500 
cubic feet—used in this process is said to be obtainable in 
an almost unlimited quantity, being driven off on the first 
heating of the crude product in the manufacture of Ame¬ 
rican kerosene oil. At present this volatile distillate is 
allowed principally to evaporate into the atmosphere ; but 
it is thought that, with very little extra expense or trouble, 
it may readily be condensed and imported. This spirit 
evaporates with extreme rapidity, as might be expected 
from its low boiling-point; and the vapour proceeding 
from it, as from other petroleum spirits, is an exceedingly 
heavy one, almost as heavy, indeed, as the vapour of 
ether; hence, when mixed with air, it renders the mixture 
considerably heavier than an equal bulk of air, and this 
has been taken advantage of in the construction of what 
is certainly an ingenious arrangement, intended to be 
used as a portable gas-lamp, or, in some cases, in place of 
the ordinary gaselier. A small reservoir, communicating 
by a pipe with an ordinary gas-burner, provided with a, 
stopcock, is filled with shavings or wool, which material is 
saturated with the spirit. The air and vapour descend 
together through the pipe to the burner, and produce a 
flame apparently equal in all respects to ordinary gas, the 
air entering through a small hole at the top of the reser¬ 
voir. It is stated that half a pint of oil will be sufficient 
