Evening star. [volume] (Washington, D.C.) 1854-1972, 1909-02-14
SCIENCE NOTES.

IT frequently happens when a draw
bridge has been constructed across the
Mississippi river the channel changes so
that the movable part of the structure is
far away from the new channel. This
has been met in the design of a bridge
which Is to be- erected across that river al
Keithsburg, Ill. 1t will have ten 2OO-foot
spans. two 103-foot spans and twenty-five
57-foot spans. the weight of steel being
about 1900 tons The usual draw span
will be omitted. but a novel lift span
scheme has been substituted for it. With
this arrangement there will be two towers
connected to the ends OF the spans adjon-
ing that to be lifted. Several of the
spans are so arranged that these towers
can be placed on them and the inter
mediate span raised SO that as the chan
mel Of the river shifts. provision can be
made for raising span which will per-
NIT navigation to be continued.
An electric ferryboat plies across the
Rhine which provides regular service be
tween GOdesberg and Observation-Disclosures
and is licensed to carry 645 persons.
There is free space on wooden fore
deck to accommodate four harnessed
hicles. The boat is propelled by two
screws. each driven by 30O-volt. 80
horsepower motor The screws may be
controlled separately or together The
battery room is ventilated by portfolios
and outlet pipes. Two :;-horsepower
motors operate landing gangwaYs. The
batteries are charged on the Godesberg
side of the river through flexible cable,
which is carried aboard to plug con
tact. the landing stage consists of
pontoon, 50 feet 6 inches by 16 feet :.
inches. connecting to the shore by
bridge 81 feet long.
The oldest iron vessel in existence is
now known as the Wolverine. She was
built sixty-sx years ago and was named
the Michigan, but thar name has been
Gently appropriated for another govern
ment boat and it was. therefore, neces-
sary to change the name of the historic
craft. At the time OF her construction
the government was without any boat
on the great lakes. and this craft was
built for the purpose Of protecting our
interests along those shores. OF recent
years her function has been TO make an
annual cruise along these bodies and TO
stop at the various towns for the purpose
Of taking on recruits to serve on more i'm
portant vessels of the government The
material with which she was constructed
was dragged across the mountains from
Pittsburg to Erie. then Insignificant
town. The trip was not then. as now
matter of a few hours, when over the
same route all the ore necessary to pro-
/ duce this entire ship Is transported in half
day and in few cars. One Of the ore
trains of the present day. indeed carries
| enough ore in its eighty fifty-ton cars to
! produce the material for four such ships
! But at that time neither the ore nor the
| trains were dreamed of. The ship had
rounded out decade of service before
! the first shipment of ore came from Lake
| Superior.
| The sensitiyenesS of the human organ
| ism is gross indeed compared with that
| of the marvellous machines man has
| made
| A photographic plate coupled with a
telescope discovers millions Of stars whose
/ light the retina OF the eve could not ap-
preciate. the micraphone makes the in
| audible tread of a fly sound like the
| tramp OF cavalrymen
| The human heat sense cannot realize
! a difference of temperature beyond one
| fifth Of a degree. but the barometer. an
instrument 100000 times as sensitive as
the skin. notes difference of a mill
llonth of degree. A galvanometer