The citizen. (Frederick City, Md.) 1895-1923, 1897-01-08
Written for the Citizen.

has had three solutions. The first is
the incomplete one of Becquerel, who
in 1860 obtained good colored impress
sions of the solar spectrum and other
objects on plate coated with subchlu-
ride of silver, the incompleleness of
the process being the lack of any
means of fixing the colored pictures,
which are retained only in the dark.
The three-color method was invented
in France in 1869 by NJ. Chas. eros
and at the same time by NJ. Ducos du
Hauron, although priority of idea has
been claimed for German Three
separate uncolored negatives of the OBJ
ject are taken through screens of diff
ferent colors. From these, three I'M
colored positives are made and differ
emily colored to correspond with the
color screens. and on superstition the
three colored monochromatic positives
give c0lored picture of the model.
In an improvement of the process by
Professor Jolly, the three pictures are
obtained interviewer on "A single plate.
Though the calorS are artificial, the APP
Proclamation to the natural object can
be made very close. and il is thought
that the invention has great future
before it. The inferential method,
published by Professor Lippman in
1891, is the third. For this is used u
transparent grainless Photographic
film of any kind, which is exposed in
direct contact with mirror of mer-
curry, and on development in the ordi-
nary way yields picture appearing
brilliantly colored by reflected light
! Reflection of light through the film
during exposure is the essential feature.
Each reflected ray is thrown on the in
cident ray and interferes with the mo-
! ton, the result being a set of standing
waves surglng up and down as the
wave lengths vary in different parts of
the image, causing the film to be af-
fected in different planes or Strata
The distance between two successive
strata is the distance between two
neighboring waves, or exactly half the
wave-leD9th of the lmpressing light.
Phe developed filin contains no pig
meut, out light reflected tiom it has
cOlors corresponding III Wave-lenglh
to the intervals between the photo
graphic strata. The principle is that
OF the iridescence of soap bubbles.
Steels tempered in phen)l have neen
found by NJ. Levant to have much
greater hardness and elasticity than
those tempered in water.
a simple musical instrument ,apa-
bic o. giving very pleasing results in
the hands OF good musicians, can lie
made from a number of holIles-say
about twehty-containiug about differ
ent quantities of water. Tne height
of the water is varied acc riding t. the
pitch of the note to be obtlnetI, and
after few trials, says NJ. G. ri,san-
der, it will be possible to reproduce
all the notes aud their octa YES, incl Id
ing the sharps and flats. Tne tuning
of the apparatus, however, requires
good musical ear. The bottles are sus
pended by the neck, by means o
strings, from two broDm handles res t
ing upon the backs of two chairs or
other convenient supports, aud the
sounds are produced by stringing the
b, tiles with two drum sticks or two rul.
ers. This arrange ments Is suitable for
airsi two parts, with two Performers
one Oh each side-if desired.
In his presidential address TO the
Indiana Academy of Sciences, Mr.. A.
w. Butler, the eminent ornithologist,
declared that TAT no time in the future
will the changes in the aspects of ma
ture be 50 noticeable, so incom prehen-
sible, because of their vastness, as have
those of the century just closing"
While this statement might be true
of much of the United States, it was
intended to apply to Indiana. The
disappearance of the great forests, the
extinction of the Indian and the large
mammals, have been accompanied by
corresponding changes among the
smaller animals. Especially conspicu-
Gus has been the passing of the passen-
ger pigeons, which Indiana knows no
longer, although in the days of Wilson
and Audubon the sky was dark with
them.
British experience tends to show
that there is no such thing as insus-
ceptibility to vaccination. The public
vaccinators of London and Reading re-
port successful vaccinations in o,875
aud IA, 009 cases respectively, with no
case in which the individual was vac
ciuated three times unsuccessfuliy.
Yet not less than 1858 certificates of in
susceptibility were granted by medical
men III England and Wales during the
last year reported on fact probably
due TO the use by physicians of stored
lymph instead of that perfectly fresh,
In new French method, thin nickel
tubes are made by depositing nickel
electroly tically Oh a matrix of fusible
metal; then melting out the latter by
immersion in bath of boiling oil.
A fiyIng-machine, designed to imi-
tate bird flight, and somewhat similar
in principle to that of the unfortunate
Lillienthal, has been subject of ex-
pertinent by Herr A. Slentzel, of Alto
IA. The wings have spread of about
yards, with "a surface of 81 square
yards. They have parabolic curve of
in Il, and move through an angle of
20 degrees. The apparatus weighs rs
pounds. The engine is of special con-
struction, using compressed carbonic
acid, and yields enc horse power with
pressure of five atmospheres aud two
to three horsepower with seven to
nine atmospheres. 1t is claimed that
the machine can not only fly, but that
its speed can be varied at will.