Nov. 18, 1869 | 
contained in the same soils, producing ferric chloride, and, on the 
other hand, decomposes the ammonium carbonate eliminated 
from the organic substances of the soil, which are subjected to 
dry distillation by the heat of the invading lava. The hydro- 
chloric acid which gives rise to the sal-ammoniac of the fumaroles 
of volcanic lavas, cannot be derived from the lavas themselves, 
inasmuch as its presence is only transient ; but it is derived from 
the decomposition of the chlorides contained in the invaded 
lands. An inspection of the lava of 1850 shows indeed that 
the denuded soil has been completely burnt, and nothing is seen 
but scoria of a reddish sand, which have evidently been subjected 
to a very high temperature.—[Ann. di. Chim. app. alla Med., 
July, 1869, p. 61.] 
TicRI has observed that the flowers of the hop have the power 
of destroying the vitality of the AZycoderma vini. A quantity of 
this fungus situated at the bottom of a vessel full of wine was 
found to be so completely disorganised by contact with the hop- 
flower, that it had no further effect in promoting the fermentation 
of the wine. Tigri accordingly recommends the use of hops for pre- 
serving wine.—(Ann. di Chim. app. alla Med., July, 1869, p. 20.) 
M. Victor MEUNIER communicates to Cosmos the result of 
an experiment made in a Pasteur’s flask. Seventy-five cubic 
centimeters of urine were introduced into a flask of three hundred 
cubic centimeters capacity, boiled for five minutes, and sealed. 
At the end of fifty-seven days two clusters of vegetation appeared ; 
they proved to be a new species of Aspergillus, which the author, 
with some humour, dedicates to M. Pasteur. In another experi- 
ment, to the details of which we need not refer, M. Meunier 
discovered an additional species of Aspergillus, which he has 
named g7bhosus. 
ProFEssoR ROCHLEDER has found a new colouring ingredient 
in madder, in addition to alizarine and purpurine, its well-known 
constituents. The dye is soluble in both water and alcohol, 
crystallising from the latter in orange-yellow needles. The 
boiling aqueous solution, mixed with a little acetic acid, com- 
municates a beautiful golden tint to wool or silk. Madder root 
contains, unfortunately, too small an amount of this substance to 
render its industrial extraction profitable. 
OrrINIONs seem still divided as to the poisonous nature of 
coralline and solferino red. Two cases are reported in Cosmos, 
from which we learn that wool impregnated with these colours 
produces loss of appetite, distaste for food, and cephalalgia. The 
wool became harmless after washing. 
M. V. MARCHAND proposes to apply a chemical remedy to 
the newly-discovered disease of the vine. He thinks it certain 
that a saturated solution of sulphuretted hydrogen in water, or a 
mineral mixture which gradually evolves the gas, will effectually 
destroy the grubs which are now, in many vineyards, busily 
devouring the roots. 
“THE second part of the third volume of Dr. Kolbe’s “ Ausfiihr- 
liches Lehrbuch der Organischen Chemie” has appeared. This 
work, which will be complete in another volume, is a sequel to 
the well-known Graham-Otto’s Chemie. The portion of it now 
before us treats principally of petroleum and similar oils, resins 
and balsams, albuminous bodies, biliary and cerebral products, 
and the constituents of urine. 
GEOLOGY 
Steneosaurus 
Mr. J. W. HuLke has published an elaborate description of 
the remains of a fossil crocodile from the Kimmeridge clay of 
Dorsetshire, which he identifies with Cuvier’s Dewxiéme Gavial 
@’ Honfleur, named Stencosaurus rostro-minor by Geoffroy Saint- 
Hilaire, and also as belonging to Quenstedt’s genus Dakosaurus. 
The last-named genus will therefore be synonymous with Steneo- 
saurus (Geoff. St.-Hil.).—[Quart. Journ. Geol. Soc., No. 100.] 
On Sphezrodus Gigas 
In a paper containing descriptions of two new species of 
Gyrodus, Sir Philip Egerton has described and figured the 
vomer of Sfherodus gigas, the discovery of which is interesting 
as proving the validity of the genus. In its character it is quite 
distinct from the same part in Zefidotus, to which genus the 
species has been referred on account of the resemblance of the 
detached teeth. The specimen figured contains a median row 
of six circular teeth, on each side of which is a row of seven 
NATURE 
89 
rather smaller circular teeth. Sir Philip Egerton also describes 
and figures a beautiful specimen of the vomer of a Gyrodus from 
Kimmeridge, which he ascribes to one of his new species.— 
(Quart. Journ. Geol. Soc., No. 100.] 
The Geology of Thrace 
Dr. A. Bout, who has been investigating the geology of 
Thrace, announces some of the results of his expedition. He 
has traced the cretaceous and nummulitic formations from Jarim 
Brugas to Adrianople, and found crinoids in the shales and 
limestones near Eski Sara, one of which he is inclined to identify 
with the carboniferous limestone. The steep southern declivity 
of the Balkan represents a great fissure of dislocation, the 
granitic central stock of the ancient Balkan having sunk down 
bodily during the enormous porphyritic and trachytic eruptions ; 
hot water flows from the fissures of the sunken granite, and 
forms numerous baths along the foot of the Balkan. In Mechli 
ravine, near Kisantik, immediately surrounded by mountains 
4,000 feet in height, Dr. Boué discovered, resting directly upon 
gneiss, an old carboniferous formation, with three beds of good 
coal; but as no fossils were to be detected in the deposit, he 
was unable to determine whether it belongs to the coal measures. 
Coal-beds, probably of Eocene age, occur in the Rhodopi.— 
[Proc. Imp. Geol., Institute of Vienna, 31st Oct., 1869.] 
PHYSICS 
The Dynamics of Prince Rupert’s Drops 
Professor Durour, of Lausanne, has been engaged in a 
research on the Development of Heat which accompanies the 
explosion of Prince Rupert’s Drops. The examination of 
bodies which, in modern language, are said to be in a state of 
“‘molecular tension” is of the highest importance to dynamics, 
and the investigation to which we now refer is an example of the 
kind of work that is really required. 
Every one is familiar with the pulverisation and explosion, so 
disproportionate to the mechanical force exerted to produce them, 
which are witnessed on the fracture of the point of one of these 
drops. M. Dufour finds, in addition, that an appreciable amount 
of heat is evolved at the same time. The simplest mode of 
exhibiting this effect is to adjust the drop in the cone of a vertical 
thermopile in such a manner as to prevent the powder produced 
by the disruption from projection elsewhere than against the upper 
face of the pile. This is easily accomplished by means of a 
caoutchouc cover, through which the point of the drop alone 
projects ; and the entire apparatus, abundantly surrounded with 
cotton, is left at rest fora day. The pile is then connected with 
a galvanometer, and, after breaking the point, the required ob- 
servation is readily made. With drops of 4°8 to 7°7 grammes, 
M. Dufour obtained a deflection of 5° to 9°. The mere friction 
of powdered glass gave no deflection. Attempts to determine 
the heat evolved were also made with the calorimeter, turpentine 
being the liquid employed. In their original form, these did not 
succeed ; but tolerably concordant results were arrived at by 
effecting the explosion in a cone of pasteboard, having its base 
uppermost, and forcing the whole of the fragments to fall through 
the truncated vertex into the turpentine. In this way, it ap- 
peared that a weight of the drops, amounting to 11°40 to 20°42 
grammes, caused an elevation of temperature of 0°25° to 0°35°. 
The internal condition of the glass was found, by these experi- 
ments, to vary appreciably in drops of different sizes. Some- 
times the product consisted chiefly of large fragments, sometimes 
it was principally powder. M. Dufour compares the state of the 
drops to a rigid enclosure bound together by highly-heated bars, 
themselves mutually connected in every direction. After cooling, 
the bars would all be under strain, from which, if released at 
one part, the whole would be set free. Now, Joule and Edlund 
have shown that a strongly-stretched wire, if allowed to return 
to its original volume, actually evolves an amount of heat, forcibly 
reminding one of that developed in the present instances. 
In order to discover the part of the drop whence the fragments 
had been derived, its exterior was coloured. Thus it was found 
that the largest fragments came from the central, the finest 
powder from the superficial layer ; and the pieces that were 
examined had, as might thence be expected, the form of a very 
flat wedge. The evolution of heat during the explosion might 
have been presumed to be accompanied by an increase in the 
density of the glass; but although this is a point somewhat diffi- 
cult to ascertain experimentally, M. Dufour’s paper is not with- 
out evidence in favour of such being really the fact. 
