234 
employed various sources of heat, including that of the electric 
lamp. ‘The lime-light he found very convenient, With the 
lime-light and concave mirror, sounds of surprising intensity 
were produced by all the highly absorbent gases and vapours. 
Among gases chloride of methyl was loudest. Conveyed 
directly to the ear by a tube of india-rubber, the sound of this 
gas seemed as loud as the peal of an organ, Abandoning the 
ear-tube, and choosing a suitable recipient for the gas, the sounds 
were heard at a distance of 20 feet from their origin. As re- 
gards intensity, the order of the sounds, in gases, corresponds 
exactly with the order of their absorptions of radiant heat. 
Among vapours sulphuric ether :tands highest, this result being 
in part due to the great volatility of the liquid. But the inten- 
sity of the sound is by no means wholly dependent on volatility. 
The specific action of the molecules on radiant heat is as clearly 
shown in these experiments as in those previously conducted with 
the experimental tube and thermopile. Upwards of eighty 
vapours have been tested in regard to their sound-producing 
power. 
With regard to aqueous vapour, whose action upon radiant 
heat even the latest publications on this subject describe as 7/2, 
it was especially interesting to be able to question the vapour 
itself as to its absorbent power, and to receive from it an answer 
which did not admit of doubt. A number of bulbs about an 
inch in diameter were placed under the receiver of an air-pump, 
with a vessel containing sulphuric acid beside them. When 
thoroughly dry they were exposed to anintermittent beam. The 
well-dried air within the bulbs proved silent, while the slightest 
admixture of humid air sufficed to endow it with sounding 
power. Placing a little water in a thin glass bulb, and heating 
it nearly to its boiling point, the sounds produced by the deve- 
loped vapour are exceedingly loud. The bulbs employed in 
these experiments are usually about a cubic inch in volume. 
They may, however, be reduced to one-fiftieth or even one one- 
hundredth of a cubic inch. Whena minute drop of water is 
vaporised within such little bulbs, on their exposure to the inter- 
mittent beam loud musical sounds are produced. 
It is to be borne in mind that the heat employed in these 
experiments, coming as it did from a highly luminous source, 
was absorbed in a far smaller degree than would be the heat 
from bodies under the temperature of incandescence. 
To render the correlation of sound-producing power and 
adiathermancy complete, all the g-ses and vapours which had been 
exposed to the intermittent beam were examined as to the 
augmentation of their elastic force through the absorption of 
radiant heat. A glass cylinder, 4 inches long and 3 inches in 
diameter, had its ends closed with transparent plates of rock- 
salt. Connected with this cylinder was a narrow (J-tube, con- 
taining a coloured liquid which stood at the same level in the 
two arms of the J. The cylinder could be exhausted at 
pleasure or filled with a gas or vapour. When filled, the 
sudden removal of a double-silvered screen permitted the beam 
from the lime-light to pass through it, the augmentation of 
elastic force being immediately declared by the depression of 
the liquid in one of the arms of the J-tube and its elevation in 
the other, The difference of level in the two arms gave, in 
terms of water-pressure, a measure of the heat absorbed. With 
the stronger vapours it would be easy with this instrument to 
produce an augmentation of elastic force corresponding to a 
water-pressure of a thousand millimetres. As might be expected 
the intensity of the sounds corresponded with the energy of the 
absorption, varying from ‘‘ exceedingly strong,” ‘‘ very strong,” 
“strong,” ‘‘moderate,” ‘‘weak,” to ‘‘inaudible.” In this 
connection reference was made to the interesting experiments 
= Prof, Rontgen, an independent and successful worker in this 
eld. 
In conclusion, the lecture draws attention to the bearing of its 
results upon the phenomena of meteorology. The views of 
Magnus regarding the part played by mist or haze, are referred 
to and attention is directed to various observations by Wells 
which are in opposition to these views. The observations of 
Wilson, Six, Leslie, Denham, Hooker, Livingstone, Mitchell, 
Strachey, and others are referred to and connected with the 
action of aqueous vapour upon solar and terrestrial radiation. 
Many years ago the lecturer sought to imitate the action of 
aqueous vapour on the solar rays by sending a beam from the 
electric light through a layer of water, and afterwards examining 
its spectrum. The curve representing the distribution of heat 
resembled that obtained from the spectrum of the sun, the 
invisible calorific radiation being reduced by the water from 
NATURE 
. Spl Se a a a ae, Se 
‘ - . 
[Fan. 5, 1882 
nearly eight times to about twice the visible. Could we get 
above the screen of atmospheric vapour, a large amount of the 
ultra-red rays would assuredly be restored to the solar spectrum. 
This conclusion has been recently established on the grandest 
scale by Prof, Langley, who on September 10 wrote to the 
lecturer from an elevation of 12,000 feet on Mount Whitney, 
“‘where the air is perbaps drier than at any other equal altitude 
ever used for scientific investigation.” An extract from Prof. 
Langley’s letter will fitly close this summary :—‘* You may,” he 
says, ‘‘be interested in knowing that the result indicates a great 
difference in the distridution of the solar energy here from that 
to which we are accustomed in regions of ordinary humidity, 
and that while the evidence of the effect of water-vapour on the 
more refrangible rays is feeble, there is, on the other hand, a 
systematic effect due to its absence, which shows, by contrast, 
its power on the red and ultra-red in a striking light. These 
experiments also indicate an enormous extension of the vultra- 
red rays beyond the point to which they have been followed 
below, and being made on a scale different from that of the 
Jaboratory—on one indeed as grand as nature can furnish—and 
by means wholly independent of those usually applied to the 
research, must, I think, when published, put an end to any 
doubt as to the accuracy of the statements so long since made by 
you, as to the absorbent power of water-vapour over the greater 
part of the spectrum, and as to its predominant importance in 
modifying to us the solar energy.” 
SOCIETIES AND ACADEMIES 
LONDON 
Royal Society, December 8.—‘‘ On the Electrolytic Diffu- 
sion of Liquids,” by G. Gore, LL.D., F.R.S. In this com- 
munication the author has described an apparatus, and an 
attempt made with it, to ascertain more definitely than he was 
able in a previous research (on ‘‘the Influence of Voltaic 
Currents on the Diffusion of Liquids,” /rec. Roy. Soc., No. 
213, 1881) whether, when an electric current is passed vertically 
through the boundary surface of mutual contact of two electro- 
lytes lying upon each other in a narrow vertical glass tube, the 
mass of either ot the liquids expands or moves as a whole in the 
line of the current, and also to obtain additional data to assist in 
explaining the phenomena observed in the previous research, 
The results obtained with a solution of mercuric nitrate (sp. 
gr. 1°30) below, and a solution of cupric nitrate (sp. gr. 1°22) 
above, showed, first, and most conclusively, that the upper 
liquid diffused downwards continuously through the meniscus in 
the glass tube (the meniscus remaining motionless) during the 
passage of an upward electric current; and second, that either 
no manifest expansion occurred in the liquid next the cathode in 
the upper solution, and that equal volumes of liquid diffused in 
two opposite directions through the meniscus; or that any ex- 
pansion of the upper liquid was compensated for by downward 
diffusion of an equal bulk of that liquid. Another possibility 
was tbat the united volumes of metallic-electro deposited copper, 
and of the acid element from which it had been separated by 
electrolysis, were greater than before such separation, and that 
this was exactly compensated by the volume of liquid diffused 
downwards through the meniscus. 
Zoological Society, December 13.—Prof. W. H. Flower, 
F.R.S., president, in the chair.—Mr. Sclater exhibited and 
made remarks on two skins of a Rail from Macquarie Island, 
south of New Zealand, which had been sent to him by Sir 
George Grey, K.C.B.—Mr. H. Seebohm exhibited and made 
remarks on specimens of the Rusty Grakle (Scolecophagus ferru- 
gineus) and Pallas’s Great Grey Shrike (Zamius major), which 
had been shot near ‘Cardiff, and were new to the British avi- 
fauna.—A communication was read from Mr, Clements RK. Mark- 
ham, F.R.S., containing an account of his researches into the 
former whale-fishery of the Basque Provinces of Spain.—Messrs. 
J. J. Lister and J. ]. Fletcher read a paper on the condition of 
the median portion of the vaginal apparatus in the Macropo- 
didz, in which they arrived at the following conclusions :—(1) 
In the Macropodide the median vaginal canal is closed in early 
life. (2) In the genera Macropus, Halmaturus, and Petrogale 
(and perhaps also Dorcopsis and Dendrologus) an opening is 
formed, leading directly from the median vaginal canal into the 
urogenital sinus, which opening most probably gives passage to 
the young. This opening may be formed early in life, as is 
usual in the genus Ha/maturus, or not till young are about to be 
