— 
Fan. 11, 1883] 
NATORE 
259 
down the pressure, the same phenomena occur in the reverse 
order, All the parts of the flame spectrum, as seen in a Bunsen 
burner, are increased in intensity as the pressure is increased. 
The fact that the effects of high pressure are so similar to those 
produced by the use of a condenser at lower pressures, seems to 
point to high temperature as the cause of those effects. But 
against this, we have the fact that at reduced pressure we get in 
carbonic oxide, the carbonic oxide spectrum and the line spectra 
of carbon and oxygen simultaneously, without that of the hydro- 
carbon flame. As we cannot doubt that a very high temperature 
is required to give the line spectrum of carbon, we must suppose 
that reduced pressure is unfavourable to the stability of the 
molecular combination, whatever it be, which gives the hydro- 
carbon flame spectrum. Wesendonck has remarked (doc. cit..) 
that in carbonic acid at pressures too low for the fame spectrum 
to be developed without a jar, it is only in the narrow part of 
the tube that the use of a jar brings out that spectrum. It 
would appear, therefore, that the constraint, due to the confined 
space in which the discharge occurs, has the same effect, in 
regard to the stability of the combination producing the spectrum 
in question, as increase of pressure. 
Cyanogen Flame Spectrum.—Our former observations ‘* On 
the Flame Spectrum of Cyanogen Burning in Air’’ were made 
on cyanogen gas, prepared from well-diied mercury cyanide, 
which was passed over phosphoric anhydride, and burnt from a 
platinum jet fused into the end of the tube. We observed what 
Pliicker and Hittorf had noted, that the hydrocarbon bands were 
almost entirely absent, only the brightest green band was seen, 
and that faintly. When gaseous cyanogen is liquefied by the 
direct pressure of the gas, the researches of Gore (Proc. Roy. 
Soc., vol. 20, p. 68) have shown that it is apt to be contaminated 
with a brownish, treacley liquid, which probably arises from the 
imperfectly purified or dried cyanide of mercury. In oder to 
obtain pure cyanogen, we have prepared quantities of liquid 
cyanogen, not by compression, but by passing the already cooled 
gas into tubes placed in a carbonic acid and ether bath. By this 
method of condensation any easily liquefiable substances are 
isolated, and any permanently gaseous substance escaped. The 
samples were sealed up in glass tubes into which different reagents 
were inserted. After such treatment the cyanogen was used for 
the production of the flame in dry air or oxygen. ‘The liquid 
cyanogen was left in contact with phosphoric anyhdride, Nord- 
hausen sulphuric acid, and ordinary sulphuric acid. By means 
of a special arrangement of glass tubing surrounding the flame 
dry oxygen could be supplied, or oxygen made directly from 
fused chlorate of potash could, by means of a separate nozzle, 
be directed on to the flame, and thus perfectly dry and pure 
gases used for combustion, Liquid cyanogen which had remained 
in presence of the above reagents gave only the single green 
hydrocarbon flame line faintly in dry air, all the cyanogen violet 
sets being strong. When oxygen made directly from chlorate of 
potash was directed on to the flame, allithe hydrocarbon flame 
sets appeared with marked brillianey. The set of lines which we 
have formerly referred to as the three set of flutings of the 
cyanogen spectrum, showed marked alteration of brilliancy with 
variations in the oxygen supply. Thus, liquid cyanogen 
purified by the action of the above reagents, does yield the 
spectrum of hydrocarbon flames on combustion in pure oxygen. 
From the great precautions we have taken, we feel sure that the 
amount of combined hydrogen in the form of water or other 
impurities in the combining substances must have been exceed- 
ingly small, and that the marked increase in the intensity of the 
flame spectrum, when oxygen replaces air is essentially connected 
with the higher temperature of the flame, and is not directly 
related to the amount of hydrogen present. This being the case, 
it must be admitted that the flame spectrum requires a higher 
temperature for its production during the combustion of cyanogen 
than that which is sufficient to cause a powerful emission of the 
special spectra of the molecules of cyanogen. Now, the two 
compounds of carbon, which give the highest temperature on 
combustion are cyanogen and acetylene. Both of these com- 
pounds decompose with evolution of heat, in fact, they are 
explosive compounds, and the latent energy in the respective 
bodies is so great that if thrown into the separated constituents a 
temperature of near four thousand degrees would be reached. 
The flames of cyanogen and acetylene are peculiar in this 
respect, that the temperature of individual decomposing molecules 
is not dependent entirely on the temperature generated by the 
combustion, which is a function of the tension of dissociation 
of the oxidised products, carbonie acid and water. We have no 
means of defining with any accuracy the temperature which the 
particles of such a body may reach. We know, however, that 
the mean temperature of the flames of carbonic oxide and 
hydrogen lies between two and three thousand degrees, and if 
this be added to that which can be reached by the substance 
independently, then we may safely infer that the temperature of 
individual molecules of carbon, nitrogen, and hydrogen in the 
respective flames of cyanogen and acetylene may reach a temper- 
ture of from six to seven thousand degrees. 
A previous estimate of the temperature of the positive pole 
in the electric arc made by one of us, was something like the 
same value. 
The formation of acetylene in ordinary combustion seems to 
be the agent, through which a very high local temperature is pro- 
duced, and this is confirmed by the observations of Gouy on the 
occurence of lines of the metals in the green cone of the 
Bunsen burner, which are generally only visible in spark spectra. 
On this view acetylene is a necessary agent in the production of 
the flame spectrum duringcombustion. The fact that the flame 
spectrum is often invisible when the arc is taken in a magnesia 
crucible, although the cyanogen spectrum is strong, but may be 
made to appear by introducing a cool gas or moisture, must be 
accounted for by an increased resistance in the are producing 
temporarily a higher mean temperature. The experiments in 
course of execution, where the arc will be subject to a sudden 
increase of pressure, will, we trust, solve this difficulty. 
Further evidence of the high temperature of the cyanogen 
flame is afforded by the occurrence in the spectrum of that flame, 
when fed with oxygen, of a series of flutings in the ultra-violet, 
which appear to be due to nitrogen. The series consists of four, 
or perhaps more, sets, each set consisting of a double series of 
lines overlapping one another. The lines increase in their 
distance apart on the more refrangible side, otherwise the 
flutings have a general resemblance to the B group of the solar 
spectrum, 
The four sets commence approximately at about the wave- 
lengths 2718, 2588, 2479, 2373 respectively. They are frequently 
present in the spectrum of the arc taken in a magnesia crucible, 
and show strongly in that of the spark taken without a condenser 
either in air or nitrogen. As they appear in the spectrum of the 
spark in nitrogen, whether the electrodes be aluminium or 
magnesium, and do not appear when the spark is taken in 
hydrogen or in carbonic acid gas, they are in all probability due 
to nitrogen. When a large condenser is used they disappear. 
Linnean Society, December 21, 1882.—Alfred W. Bennett, 
M.A., in the chair.— Prof. Adolph. Ernst, of Venezuela, and 
Dr. W. C. Ondaatje, of Ceylon, were elected Fellows.—Prof. 
T. S. Cobbold exhibited specimens of Ligules from the Bream, 
the Minnow, and the Grebe to compare with tho:e from man. 
The worm from the Bream is called Z. edudis by Briganti, and 
is eaten under the name ‘‘macaroni piatti.’—Mr. T. Christy 
called attention to experiments lately made, which show that the 
Kola nut possesses singular properties of clearing fermented 
liquors.—Mr. Thos. H. Corry read a paper on the development 
and mode of fertilisation of the flower in Asclepias Cornutt. R. 
Brown, 1809, J. B. Payer, 1857, and thereafter H. Schacht, 
have made Asclepias the subject of interesting study ; Mr. Corry 
nevertheless has added new observations thereto, He finds that 
the petals and stamens, which in the early stage originate sepa- 
rately, become afterwards adnate; the stamens, moreover, by 
their broad filaments form a fleshy pentagonal ring, ze. are 
monadelphous. The ‘‘ s¢¢gma-disk” is not formed by the fusion 
of two stigmas, for the styles proper remain distinct throughout 
their entire extent. The greatest analogy of the flower to that 
of the Apocynacez is at this period ; thereafter differences 
ensue. From a careful study of the different stages of the pollen 
in Asclepias it appears to exhibit a perfectly isolated and peculiar 
case of formation. The idea that self-fertilisation can take 
place with the parts zz sif« is shown to be impossible, 
and the need for insect or artificial aid rendered impera- 
tive. Cross-fertilisation is the great law in the Asclepiads. 
—Dr. F. Day read a paper, ‘‘ Observations on the Marine 
Fauna of the East Coast of Scotland,” founded on a recent 
survey by H.M.S. Zion off Aberdeen, Kincardine, and Forfar. 
As regards the herring and its migrations, they shift their locality 
for breeding purposes or in search of food, occasionally being 
driven from a spot where extensive netting or other causes dis- 
turb them. The herring seems of late years to take to deeper 
water off shore, but at times they appear to return to their old 
