The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1891-03-17
MIS-

The plates were exposed three hours,
and development brought out bright
and dark bands across the direction of
vibration, and dark bands in the direc-
ton of vibration.
French experiments in connection
with aerial navigation have shown an
astonishing strength in alloys of alumni
mum and copper. With only 2 per
cent. of copper the tensile strength of
aluminium was increased from about
81, 900 to nearly 4 1000 pounds per
square inch, and the addition of 6 per
cent. of copper more than doubled the
strength of aluminium while adding
but one-twentieth to it's weight.
AUsEFoRM osQUTToEs.-Th practice
of inOculating new residents of Cuba
with yellow fever conveyed by mos
quito bite has been continued by Drs.
Finlay and Delgado, Of Havana, for
ten years. They now report completed
observations on 50 cases of mosquito
incubation, in Only8 per cent, of which
was yellow fever contracted in a well
marked form, with a mortality of less
than 2 per cent. Of IS monks, who
arrived in Havana and lived there
under similar conditions, 50 were inOcu-
lated and 80 were not, only 2 of the
former having well marked ~attacts, in
neither case fatal, while there we're II
severe cases among the ~uninoculated,
and not lessthan 5 deaths.
PERFECTION OF THE DYNAMo.-Mr.
A. B, Blackburn, Of the Manchester
Association of Engineers, concludes
that the dynamo has been brought to
such perfection in the last few years
that little radical change can be ex-
pected in it's general proportions and
design. It's efficiency is already so
high that increase is scarcely possible,
being rarely less than 80 per cent, and
In the best machines over 80, and even
as high as 95, per cent. It is probable
thatfuture improvements will be chiefly
in details Of construction, labor saving
in production, and perhaps new and
less p~erishable insulating materials;
the most important problem yet to be
solved being the abolition Of the vari-
able sparkling point.
TREATMENT OF LOCKJAw.-It was not
long ago discovered in Germany that
inoculations with the blood of a victim
of lockjaw fail to produce the disease;
but that fluids from the wounds caus-
ing the lockjaw invariably give rise to
it. This indicates that the specific
poison of lOckjaw remains near it's
point of entrance, and that local treat
ment is necessary. Acting on this
theory, DR.. Pavilini recommends sub
cutaneOus injections of carbolic acid.
A severe case of lOckjaw in a boy of
Is vas on the fourth day treated with
injections of a %One-cent. solution of car
bOlic acid nea the wound in the foot,
and this was continued at intervals in
01ooocInOe fnOoo +hrOn L01Jv.C v1-417 4Lo
9th day. The boy recovered.
CURIOUS USE OF MICROBEs.-A Nor
wegian naturalist, DR.. Nelson, states
that fishermen in his country have been
catching whales with the aid of disease
bacteria for more than five centuries.
Every season whales enter a narrow
inlet of the sea lear the town of Bergen,
and when is discovered the fisher
men go out in boats, drive him farther
up the narrow bay and stretch a net
across the mouth of the inlet. Their
primitive implements are insufficient
alone to capture and land the animal
thus imprisoned, which is usually 90
or 80 feet long, and very strong. They
accordingly shoot into him arrows
infected with the poison of some in
fictitious disease-apparently sympa-
thetic anthrax-and in "a or So hours
he becomes SO weakened by the growth
of bacilli in the wounds that men with
harpoons are able to land him.
MORE ABOUT GOLD-SnvER.-The gold
colored a%llotropic silver described by
M. @. Lea, of Philadelphia, about two
years ago has been subjected by him to
further study. 1t is found that allo-
trOpic silver-which may be produced
in a great variety of c~olors, such as
~gold-color, ~copper-color, blue, blush
green, red and purple-may be pre-
sented in a form intermediate between
that already made known and ordinary
silver. and differing in a marked way
from both. All forms of energy act
upon a%llOtropic silver, converting it
into ordinary silver or into the inter
mediate form. Mechanical fOrce-even
slight friction-and high tension cleo
tricity convert it directly into ordinary
silver. Heat and chemical action CON
vert it first into the intermediate form,
then into ordinary silver. The action
of light is to produce the intermediate
form only, and prolonged action at or
binary temperatures does not carry it
beyond this. Conversion to ordinary
silver occurs spontaneously in the
course of time even In the dark. A
connection is evident between these
varied and wonderful transformations
of pure silver and the changes which
many silver salts undergo through the
action of light.
ELECTRICITY GENERATED BY LIGHT
Since 1877 Prof. G. NJ. Minchin has
been making experiments in photo
electricity, Of which an account has
just been given to the Physical Society
of London. Electric currents are pro
duced by the action of light on silver
plates coated with colodDn or gelatine
emulsions of bromide, chloride, iodide,