Sacramento daily record-union., 1881-03-11
POPULAR SCIENCE.

modes OF Sensibllity OF the Visual appara-
tus, the London Times reports, has been
made by Mr.. Chambers. He has been ex-
perimenting by looking IN darkness at an
opaque screen in which was perforated
three or four minute holes, quite near each
other, but distinguishable when medium
light shone through. Light was raised
from zero on the other side; it was some
times colored. The order of phenomena
was proved TO be this: The first action OF
light entering the eye IN very small guam
tity is in all cases merely to produce diff
fuse luminous sensation not differentiated
either as to color or as to form with
greater quantity one gets the notion OF
color if there be color in the light; and
still more light is required to be able to
resolve the luminous object into its differ
ent elements Luminous sensibility is the
most simple reaction then comes chro-
matte sensibility, by which we distinguish
color, and, lastly, what the author terms
visual sensibility, by which we distinguish
form.
At late meeting of the French Acad-
emy of Science, III. Dunand read paper
on a method of producing speech IN elec-
tric condensers, and particularly IN the
singing condenser He connects one pole
of the battery with one end of the induced
wire of the coil, the other pole with one
armature of the condenser, while the Sec
ond armature is attached 70 the other end
of the induced wire. In the circuit of the
primary coil battery and carbon micro
phone are introduced. In this way speech
may be produced with great clearness.
The condenser which gave the best results
was 006 meters in length of side, and
contained thirty-six sheets of tinfoil. For
the auxiliary battery two or three Leclanche
elements gave weak articulate sounds.
The intensity increases with the increase
of the number of elements, but not pro-
portionally. The current of the auxiliary
coil does not traverse the condenser.
The Electrician describes microphone,
invented by NJ. Bcudet, of Paris, which
transmits articulate speech very distinctly
| without altering the tone or causing any
| scratching noise. 1t is composed Of a
mouthpiece of the usual telephone kind,
joined to the end of glass tube, cent?
meter in diameter, which is mounted on a
jointed stand. The mouthpiece contains
an ebony plate, one millimeter thick, to
which is attached piece of copper, pene-
trating the glass tube little distance. In
the tube are six carbon balls. At the end
of the tube there Is a piece OF copper,
which imparts the necessary degree of
pressure to the carbons. In action this
microphone of multiple contacts is like an
ordinary middle-sized Gaiffe microphone,
with six elements-peroxide of manganese
and chloride of zinc-set up with resist
ance of so ohms, with Bell telephone for
a receiver.
Mr.. Covers form of the Bell telephone
has been adopted by the British Postoffce
authorities, who have given an order for
twenty thousand of the instruments. 1t
has been tried on the Southwestern rail-
way, England, with much satisfaction in
communicating with the signal cabins on
different sections of the line. The tele.
phones were simply connected between the
existing wire for working the "block "
system and the "earth." Conversation
was then distinctly carried on without
interfering in the least with the ordinary
signals. It was interesting to hear through
the telephone the sound of the train itself
leaving the distant station at the same time
as the strokes of the signal bell announced
the departure.
Prof. Balfour Stewart considers that the
evidence is in favor of some connection be.
tween the state Of the suns surface and
terrestrial meteorology, whiia at the same
time it is Enthusiastically indicated by all
elements that this connection is of sueh
nature as to imply that the sun is mcst
powerful when there are most spots on his
| surface. He does not, it will be perceived,
commit himself unreservedly to this view,
and he thinks that further research is nee
essary to clear up many points still in
doubt. But he is free to say that, Sin
fine, this hypothesis is rapidly emerging, if
indeed it has not already emerged, from
the regions of mere conjecture.
A material which has been proposed for
the filtering and decolorizing of sugar and
| other substances consists of dried or baked
granulated clay mixed with blood in the
proportion of three parts of clay to four of
blood. Sometimes vegetable charcoal Is
added. The mixture is nodded into Jumps
of any convenient fern, dried, broken into
small pieces, mixed with an equal bulk of
granulated clay, and after having been
carbonized IN retort, carefully screened.
The screenings are said to answer admira-
| bly, the purpose for which they are designed.
The first application of electricity to
permanent street lighting in Glasgow has
Just been made in portion of Buchanan
street. The lamps used were those invented
| by Mr.. Brockie. Gramme machines sup
piled the electricity, and they were driven
by an Otto gas engine-gas thus curiously,
it was remarked, superseding itself as
means of illumination. Some of the lead
ing newspaper offices in Glasgow have
made arragements for lighting up the
business and the composing rooms with
electricity.
A Mr.. St. George Lane Fox has been
working on an electric lamp on the same
principle as Mr.. Edison's, and it would
seem from report of private exhibition
of the efficiency of this lamp that Mr.. Fox
has been very successful. The tests were
made on the 7th inst, at the Office of the
British Electric Light Company, London.
1t is claimed that the Fox incandescent
lamp will last for years if subjected "to
ordinary average use"
The French Academy of Science have
appointed commission, under the presi-
dency of NJ. Dumas, to make the necessary
arrangements for observing the transit of
Venus in 1882 It is thought that R. A.
Proctor will be intrusted with the super.
intendence of the English arrangements.
Messrs Garreau and Machelart (Comptes
Rendus, No. 23) have extracted from the
stems of the saxifrages, tannin, starch, and
new proximate principle, bergenine,
which possesses valuable medicinal proper
ties, and may rank between quinine and
salicine.
The tea plants grown by Count d'Amigo
on his estate near Messina, produce leaves
which are said to be as good as those of
the plants raised in China. There is to be
systematic attempt now made to grow
the tea on a commercial scale.
AN UNFORTUNATE MISTAKE.