According to _Nature_, the much-dreaded scourge of the vine, the
Phylloxera, has made its appearance in the vineyards of the Cape
Colony. Some years ago, the most stringent regulations were made to
prevent, if possible, the importation of these unwelcome guests. The
Cape government even refused to allow consignments of beech-trees from
England and tree-ferns from New Zealand to be landed in the colony, and
fixed a very heavy penalty as a punishment for any infringement of the
law. But by some mysterious agency, two or three of the vineyards are
swarming with the Phylloxera. The most approved insecticides, carbon
disulphide, &c., have been telegraphed for, for they are not at hand in
the colony, and in the meantime the affected vines are being uprooted
and burnt.
A curious instance of tenacity of vitality in low forms of life has
been discovered by Professor Leidy. Upon examining a block of ice which
formed part of a large quantity stored at Moorestown, N.J., and had
been so stored for more than twelve months, he found it riddled with
air-bubbles and drops of water. Upon melting a portion of the block,
a number of worms made their appearance. They died almost immediately
when liberated from their frozen prison. The worms cannot be identified
with any known species, and Professor Leidy believes them to be of a
form as yet undescribed.
It is satisfactory to note that the Emperor of Brazil has given orders
for a photographic astronomical apparatus like that employed so
successfully by MM. Henry of Paris, in order that Brazil may do its
share in the proposed photographic survey of the heavens initiated by
the French astronomers named.
Lloyd’s agent at Athens has recently reported some information as to
the progress of the canal which is to cut the Isthmus of Corinth. Out
of a total of thirteen million cubic yards of earth which must be dug
out before the canal is completed, nearly three millions have been
removed. The canal is to have a surface width of twenty-four yards,
except at the entrances, which will be widened to between fifty and
sixty yards. One thousand men are at present employed upon the works,
which, at the present rate of progress, should be completed in five
years.
The Austrian government offer a prize of one thousand ducats (nearly
five hundred pounds) for the discovery of a system of working coal in
fiery mines without shot-firing. The method must not be more expensive
than that of ordinary blasting. It must not be capable of igniting
fire-damp or coal-dust, and it must not leave any injurious products
behind it. These are the chief conditions.
An improved method of etching metallic surfaces has been invented by
Mr A. Piper of Wolverhampton. The metal surface is first of all coated
with gold, silver, nickle, brass, or any other metal desired, in the
ordinary electro-plating bath. The design is then drawn upon it in some
resinous or other acid-resisting medium, and the metal is immersed in
an acid, which eats away the coating, and at the same time produces a
dead or frosted appearance upon the exposed metal beneath. The resinous
drawing is now removed by any suitable medium which will dissolve it,
leaving the design in relief upon a frosted ground. If desired, the
operation can be reversed by leaving a groundwork of plated metal,
while the design is bitten out by the acid.
A new stationary buffer-stop for railway stations and sidings was
recently described in a paper read before the Institution of Mechanical
Engineers by Mr A. Langley of Derby. This buffer-stop consists of two
hydraulic cylinders fitted with pistons. The piston rods carry in front
buffer-heads to meet those on the locomotive. There are also projecting
rods behind the cylinders connected by chains with counterweights, to
return the pistons after pressure to their former position. The pistons
have a stroke of four feet; and it is calculated that this amount of
depression would effectually stop a train without jerk or damage even
if it were moving at the rate of eight miles an hour.
Gases inclosed in iron cylinders under enormous pressure are now used
in various branches of science and art, and are supplied commercially
by many firms in various countries. The gases most commonly used are
hydrogen and oxygen—for the lime-light—carbon dioxide, and nitrous
oxide—this last being much employed as an anæsthetic by dentists.
Hitherto, there has been much difficulty in controlling the outrush of
gas from these cylinders, for the internal pressure often amounts to
six hundred pounds on the square inch. By the aid of a new regulator,
invented by Messrs Oakley and Beard of London, this difficulty is at
once obviated. The regulator consists of a small india-rubber bellows
inclosed in a brass box, which screws upon the nozzle of the gas
cylinder. By an ingenious device, as the bellows top rises with the
pressure of the gas, a screw valve descends upon the opening in the
cylinder. In this way the user of the gas can regulate the outflow to
his requirements. We understand that it is in contemplation to adapt
the same principle to ordinary gas consumption in houses, so that the
supply may always be adjusted to the number of burners in actual use.
Habitual drinkers of aërated beverages were some time ago startled
by the report that the original source of the water used in the
manufacture did not much trouble the attention of the vendors, and
that micro organisms in fabulous numbers might find their way to
the consumers of these apparently innocent fluids. According to Dr
T. Leone’s researches, aërated waters are peculiarly safe from such
contamination. Taking a typically pure potable water, he tried how many
micro organisms could be developed in it in a given time. In five days
the water contained immense numbers of organisms. But when charged
with carbonic dioxide, as all aërated waters must be to give them
their effervescent quality, the number of living creatures was at once
diminished. Water so charged contained at the end of fifteen days only
a mere trifle of the original organisms. Dr Leone therefore concludes
that the longer aërated waters are kept, the less chance is there of
bacterial contamination.
The greatest living authority on bacteria, M. Pasteur, has by recent
experiments proved that water containing only two per cent. of
concentrated sulphuric acid possesses the property of destroying these
organisms. He recommends that this acidulated water should be used as a
disinfectant for floors of stables, mangers, courtyards, cattle-sheds,
&c. The compound has certainly the merit of extreme cheapness, for
about twelve gallons could be prepared at a cost of twopence. We may
mention that M. Pasteur’s inoculations for hydrophobia have met with
unlooked-for success. He recently told the Paris Academy of Sciences
that out of three hundred and twenty-five cases of inoculation for
this terrible disease, only one had proved a failure, and that one he
attributed to delay. It is suggested that an international hospital
should be established for the reception of patients from every country.
The all-seeing microscope has very often played an important part
as an accusing witness, more especially in the identification of
blood-stains. Recently in Illinois the same detective agent was
instrumental in hanging a murderer; but the method of conviction was
novel. Here is the case: A. had been found murdered while sleeping on
a pile of sawdust in a certain icehouse, which we will call No. 1. B.
was suspected of the crime because particles of sawdust were found on
his clothing and on his boots. He accounted for this by pleading that
he had been sleeping in another icehouse (No. 2) which was far away;
and declared that he had not been near the No. 1 house. It was proved
that icehouse No. 1 contained _pine_ sawdust, and house No. 2 hardwood
sawdust only. The microscope showed that the clothes and boots had
attached to them particles of the former only. The man was convicted
and executed.
Professor Vogel has lately brought forward the curious fact that the
generation of alkaloids in plants is dependent upon sunlight. The
hemlock plant which yields coniine in Southern Europe contains none
in Scotland. Again, the tropical cinchonas, from which quinine is
obtained, will yield very little of that valuable product if cultivated
in our weakly lighted hothouses. Professor Vogel has examined many
specimens of the plant from various conservatories, and has been quite
unable to obtain the characteristic reaction of quinine, although
the method of testing is a delicate one, and sensitive to minute
quantities of the alkaloid. It is curious to observe that although
sunlight seems so necessary to the formation of quinine in the living
plant, it acts most injuriously upon the alkaloid in the stripped bark.
In the latter case, the quinine is decomposed by it, and assumes the
form of a dark-coloured resin. Because of this, in the manufacture of
quinine, the bark is always dried in the dark.
The recent severe weather must have led many a half-frozen traveller
to wonder if our railway and tramway Companies will ever hit upon
some method of heating public conveyances. With a steam-engine as
a necessary adjunct, it would seem to the disinterested inquirer
that a method of warming by pipes fed from the ‘exhaust’ would be a
comparatively easy way of managing the business, and would at the same
time save much labour in doing away with the filling and distribution
of inefficient foot-warmers. In Chicago, a new method of heating
tramcars is being tried, and it promises well. The apparatus, which is
placed under the floor of the car, consists of a brass cylinder filled
with coal-oil, which, under pressure of a strong spring, is forced
into a small super-heater, where it becomes vaporised. This oil-gas is
ignited in a fire-clay combustion chamber, and although there is no
flame, the fire-clay is brought to a white heat. The outer air passing
over this hot box becomes well warmed, and a constant stream of fresh,
warm air is assured to the passengers. The only visible evidence of the
stove is a grating in the floor of the car through which the hot air
rises. When will our tramway Companies consent to a small reduction in
their high dividends, to afford their patrons similar comfort?
The use of wood pavements in Sydney has been very strongly condemned by
a Committee appointed by the Legislative Assembly of New South Wales to
inquire into the subject. It had been alleged that these wood pavements
exerted a deleterious influence on the health of persons living in
their proximity, and the conclusions arrived at by the Committee would
seem to justify these allegations. Analysis showed that the blocks
in actual use had absorbed a vast amount of organic matter, even
though they had only been laid down a comparatively short time. It was
evident, too, that complete impregnation of the wood was only a matter
of time. In the words of the Report: ‘So far as the careful researches
of your Board go, the porous, absorbent, and destructible nature of
wood must, in their opinion, be declared to be irremediable by any
process at present known; nor, were any such process discovered, would
it be effectual unless it were supplemented by another which should
prevent fraying of the fibre.’ It should be noted that this strong
condemnation is applied to the _hard_ wood-blocks used for the purpose
of paving in Sydney, and not to the soft wood used here at home. These
latter are so thoroughly impregnated with tar, that it is difficult
to imagine that room could be found for anything else, organic or
otherwise.
The cable tramway which is situated on the historic hill at Highgate,
London, has worked without hindrance during the recent frost and snow.
This is due to the fact that the working parts are underground. But of
late a new use has been made of the system. Heavy vehicles even with
six horses attached could not be moved up the hill during the recent
frosts. Many of them were therefore fastened to the tramcars, and were
pulled up the steep incline—one in eleven—at the rate of six miles an
hour.
In his recent lecture at the Royal Institution, Mr A. A. Common, the
treasurer of the Astronomical Society, pointed out that the old method
of eye-observation in telescopic work would probably in the near future
give way to automatic records on sensitive dry plates by means of
photography. He also pointed out what extreme variations existed in the
amount of light emitted by different celestial objects, contrasting
with the blinding glare of the sun the small quantity of light received
from a faint star. The latter he described as being equivalent to
the twenty-thousandth part of the light given by a standard candle
seen from the distance of a quarter of a mile. It is not a matter
for wonder, therefore, that the most sensitive dry plate which would
yield a photograph in daylight in the smallest fraction of a second,
should require an exposure of two hours, or thereabouts, when used for
recording the existence of one of these distant orbs.
Signor Ferrari, after making observations on between six and seven
hundred thunderstorms which occurred in Italy a few years back,
has noted that every thunderstorm is connected with a barometric,
hygrometric, and thermic depression. A German scientist who has
interested himself in the same line of inquiry, states that the danger
of a building being struck by lightning has increased in his country
during the past half-century from three to five fold. He attributes
this increase of danger to impurities carried into the atmosphere from
factory chimneys, the number of which is constantly increasing.
A new electric alarm-bell for use in places where highways and
railways cross one another has been invented in the United States.
On approaching such a crossing, the wheels of the train depress a
heavy trigger placed by the side of the rails. This trigger sets in
motion a flywheel sufficiently powerful to turn the armature of a
small magneto-machine. The current thus generated rings a bell at the
cross-road, so that wayfarers have an audible reminder of the near
approach of a train. Of course the same result might be brought about
with an electric battery. But the magneto-machine has the advantage of
requiring no attention, and of not being affected in any way by changes
of temperature. Its bearings can be provided with oil-cups, so that it
will act for months together without supervision.
Professor Ewart lately read a paper before the Royal Physical Society
of Edinburgh, in which he stated that from examinations of specimens of
‘whitebait’ sent into the London market during the past year, he had
come to the conclusion that the much esteemed little fish consisted
of sprats and herrings, about sixty per cent. of the former to forty
per cent. of the latter. The origin of so-called ‘whitebait’ has
always been such a disputed point that the Professor’s remarks are
particularly interesting. He also pointed out that in Canada, sprats
are extensively tinned as sardines. As we some time ago pointed out in
these pages, a similar trade has been for a long time carried on at
more than one place on the south coast of England. We may mention that
the authorities of the South Kensington Aquarium are about to introduce
herrings into the tanks under their control, in spite of the fact that
all such attempts, in inland places at least, have hitherto failed. We
trust that their endeavours will be crowned with success.
Messrs Fairbairn and Wells, Manchester, have lately much improved their
screw forging machine. By this method of making screws, it is claimed
that much greater tenacity, ductility, and durability are obtained in
the finished product; for the fibres of iron, instead of being cut
through, are pressed and bent round to the shape of the thread. In
short, the machine rolls out the screws, instead of cutting them out.
We have lately seen photographs of some of these screws which have been
partially eaten away with acid, for the purpose of showing the fibrous
nature of the metal. It is curious to note how the fibre is bent in and
out as it follows the direction of the thread on the screw. This method
of manufacture is said to present advantages apart from better quality.
The screws can be more quickly produced at a less cost, and there is a
great saving of material, for nothing is cut away to waste.
The results of a curious but very important test as to the accuracy
with which chemists, druggists, and others make up prescriptions
committed to their care, has recently been presented to one of the
London vestries. Fifty prescriptions were sent out to ordinary
druggists, to co-operative stores, to ‘doctors’ shops,’ and to certain
traders styling themselves drug Companies. The mixtures made were
afterwards analysed, to find out how nearly they agreed with the
prescriptions they represented; but in order to give a liberal margin
for error, it was resolved not to put a black mark against any one, if
the chief constituent were within ten per cent. of the right amount.
Notwithstanding this margin, no fewer than seventeen out of the fifty
mixtures were incorrectly dispensed. In one case the principal drug was
less by eighty-five per cent. than the amount ordered, while in another
it was fifty-seven per cent. in excess. The chemists and druggists came
out best in this strange competition, as only six per cent. of their
prescriptions had to be called in question. Next came the co-operative
stores with twenty per cent. of error; then the ‘doctors’ shops’ with
fifty per cent.; and lastly the drug Companies, who are credited, or
rather discredited, with seventy-five per cent. of errors.