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May 18, 1871] 
NATURE 
49 

enough penetrating force to pass clean through the side of 
the strongest ironclad afloat—those of the /Yevcules class 
—or, in other words, is endowed with impact sufficient to 
pierce twelve inches of iron ; and it must be remembered 
that this last-named distance is one at which gunners can 
make very good practice, so that, under ordinary circum- 
stances, every other shot would take effect against a target 
such as is presented by the keel of a large frigate. As 
regards extreme length of range, a quality of some im- 
portance, when, as in the recent instance of the Paris siege, 
great projecting power is of more importance than preci- 
sion of aim, this Fraser gun may vie with almost any 
other, with the exception, perhaps, of Whitworth’s cannon. 
The utmost distance to which “ the Woolwich infant,” as 
it has been nicknamed, will in all probability be capable 
of projecting a shellis about ten thousand yards, supposing 
the arm to be laid at an elevation of some thirty-three 
degrees. 
So satisfactory, indeed, has this experimental structure 
turned out, that a further batch of sister guns have forth- 
with been commenced, and will serve to arm some of our 
eavy iron-clads which are now building. Only a small 
number of such weapons will be carried by these vessels 
—two, or at the most four, apiece—and thus our modern 
men-of-war will present a perfect contrast to those of a 
dozen years ago, when a ship, being regarded merely asa 
box of guns, sometimes received on board as many as a 
hundred and thirty cannon. Nevertheless, a broadside 
delivered from four guns of these giant dimensions (for 
the whole armament being carried in turrets may be 
brought to bear at one time), representing almost a ton 
anda half of metal, very far exceeds that which an old 
first-class three-decker could throw into her antagonist, 
and would indeed be sufficient to sink most vessels at a 
first discharge. 
As regards the method of building up these large guns, 
we need say nothing, seeing that the subject was fully dis- 
cussed recently in these columns. It may be of interest 
to know, however, that in the present instance as muchas 
fifty tons of metal were employed in constructing the arm, 
and that at ene time thirty tons of this was brought toa 
glowing white heat for the purpose of welding. The rever- 
beratory furnace in which this massive coil was heated is 
an apartment in which a dozen persons could dine com- 
fortably, and the length of the bars before coiling amounted 
to upwards of 1,200 fect. The length of the arm is six- 
teen feet and a quarter, and its extreme diameter fifty-six 
inches. 

A NEW INEXTINGUISHABLE STORM AND 
DANGER SIGNAL LIGHT 
HIS new Signal, possessing most remarkable proper- 
ties, has now been brought before the public. It 
was first exhibited at the President’s meeting of the 
Royal Society on 22nd April, when it attracted great at- 
tention. The peculiarities of the Signal Light are, that 
it is self-igniting when placed in water or thrown on the 
sea. Contact with water being the only means of igniting 
the lamp, it is inextinguishable when once ignited ; neither 
wind nor storm has any effect upon the flame. The light 
is of intense brilliancy, and of great duration, and can 
be seen fora great distance in the open-air. Photographs 
may be taken by the light of this new signal. Experi- 
ments were tried on the evening of 25th April, at ten 
o’clock, in the presence of some scientific gentlemen, to 
determine its brilliancy as a signal. A lamp was placed 
in a bucket of water on the top of Primrose Hill, and the 
light was so intense that after the signal had been burning 
for twenty minutes small newspaper-print could be dis- 
tinctly read at a distance of seventy feet, notwithstanding 
that the night was thick and foggy. This new signal 
light will burn for over forty minutes. In construction 
the lamp is exceedingly simple, and so contrived that 

when once burnt the whole may be thrown away. The 
chemical preparation contained in the lamp is a solid, 
hard substance, free from danger ; not affected by heat, 
and so non-explosive ; and the signal is comparatively 
inexpensive. Its applications for marine signals are 
numerous. In case of shipwreck a fewlamps thrown on 
the sea would illuminate the entire scene, and enable as- 
sistance to be promptly and efficiently rendered. For 
rocket-line apparatus it is equally valuable, as, bursting 
into a flame on falling into the sea, it would indicate the 
position of the rocket-line. In connection with life buoys 
it would be a mark to the drowning sailor. In life-boat 
services it would be a signal to the vessel in distress, and 
the brilliant light would greatly assist in the rescue. In 
cases of salvage, ships’ signals, tide and harbour warnings, 
the duration of the light renders this new invention of 
great value. Asa railway signal, to be used by the guards 
and station porters in cases of accident, it is equally 
available, and will be of great utility. The difficulties of 
preparing the chemical compound have been entirely 
overcome by Messrs. Albright and Wilson, of Oldbury, the 
contractors for the manufacture of the lamp for Mr, 
Nathaniel Holmes the patentee, 

FRESHWATER BATHYBIUS 
es a late meeting of the Natural History and Medical 
Society of the Lower Rhine, the well-known zoologist, 
Dr. R. Greeff, noticed an organism inhabiting freshwater 
and approaching very nearly, both in its structure and 
mode of occurrence, the celebrated deep-sea Bathybius 
Hlaeckelit of Professor Huxley. 
Dr. Greeff, as much as three years ago, published a 
notice (in Max Schultze’s “Archiv fiir mikrosk. Anat.” 
Bd. iii, p. 396) of a new shell-less freshwater Rhizopod, 
which was remarkable for its gigantic stature in com- 
parison with all previously-known organisms of that kind. 
Hecalled attention at that time to its occasional occurrence 
in great quantity in the mud of standing waters, and 
indicated that, on account of its peculiar structure, it 
could be referred neither to the true Awd nor to the 
Actinophryes. Since that time, the author has never lost 
sight of this extremely remarkable creature, and he thinks 
it desirable no longer to keep back his observations, 
especially considering the high degree of interest that 
has been excited by the Bathydius-mud which has 
been discovered in the depths and abysses of the ocean 
(to beyond 25,000 feet). 
As regards the occurrence of this freshwater organism, 
to which the author provisionally gives the name of 
Pelobius,* and which he considers to be truly comparable 
with Lathybius, Dr. Greeff states that it is found in many 
standing waters with muddy bottom, which have appa- 
rently persisted for a long time, and seldom, if ever, have 
dried up. Thus, near Bonn the bottom of the Poppelsdorf 
fish-pond is found occasionally to be almost entirely 
covered with masses of Pelobius ; to such an extent, in- 
deed, that sometimes a glass vessel brought up from the 
bottom contains almost more Pe/odzus than true mud-par- 
ticles, &c. The Pe/odzs never disappears in these waters, 
but remains throughout the year in great masses, some- 
times in one place, sometimes in another. The cake-like 
lumps of mud which rise to the surface and float about 
there by the agency of enclosed gas and air-bubbles, 
especially during the warm season, also sometimes con- 
tain Pe/odius in masses. 
In their external form, in both the living and the con- 
tracted state, these organisms present the appearance of 
more or less spherical lumps, varying from one or two 
millim, in diameter down to the most minute points, 
scarcely perceptible by the naked eye. Middle-sized 
* From mnAdc, mud, [The name Pe/odius has been long preoccupied. — 
Ep.]] 
