Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1891-12-25

these conditions, is 600, 000, 900 gallons, for
| the supply of district covering an area Of
LOO square miles. including eight separate
townships, etc. The quantity Of concrete
used was GO, 600 cubic yards, the net time
occupied in construction being about 2X
years Special machinery was used for
mixingft the concrete and depositing it in
place, and the whole work is regarded as Q
most creditable achievement.
Copper's Strength Decreases With Heat.
The fact is well known to engineers and
metallurgists that the tensile strength of
copper decreases to q very considerable ex-
tent with rise in the temperature, and, on
this account, copper steam tubes are liable
to cause accidents of a serious character.
In view of this the Fairfield Sh1pbuilding
and Engineering Company, of Goyan, Eng
land, recently undertook series of practi-
cal experiments with the object of strength
enlng copper steam tubes by having wire
colled around them. As Delta metal 10
known to lose comparatively little in
strength with increasing temperatures, as
SHOWN by Prof. Unwin's interesting expert
ments and tests in this line, the above
named company tested Delta wire against
copper, both cold and at the Temperature Of
melting tin, namely, 1920 The result in
these various trials confirmed in an unques-
tlonable manner the greater strength so
long claimed for the Delta meta, it proving
In every instance superior to copper.
New Plans for Steamer Building.
The model of the new steamer building at
Glasgow will, it is claimed, insure tho
quickest possible transit of the Atlantic
ocean attanable by steam craft. With o
length of 63O feet and 20 feet beam, very
fine lines are obtained, and the twin screws
are OF some % feet diameter, well sup
supported. There are four tunnels, and
about 200 feet of the length of the ship is
devoted to the boilers and bunkers. The
engines, triple compound, with four cylin-
ders working four cranks, are figured at 33,.
900 horse power. Accommodation is pro-
vided Tor some 700 first and 800 second-class
passengers and about 400 emigrants, and all
the arrangements worked out in the plans
for carrying out this important feature are
far ahead, it is claimed, of anything vet
produced in nautical construction. The
plating of the ship is carried up to the prom
enade deck, which runs from end to end,
and about 90 feet on each side is left for
Remark bile Precision in Photography.
In q lecture delivered at the College de
France, NJ. Marcy exhibited to bis audience
specimens of the remarkable precision at
tanned by some OF his latest inventions in
the region of scientific photography. Hith-
erto it has been known to be possible to
produce series of negatives showing the
movements of bird on the wing, but for
more rapid motions the existing apparatus
has proved too slow, producing only blurred
impressions. As an example, in order to
photograph clearly an insect flying, it is
essential that the exposure should last only
the 1-25, ,000th part of second, and this
NJ. Marcy accomplished with new instru-
ment Of which he is the inventor. M.
Marcy concluded his demonstration by still
further reducing the period of exposure,
and Photographng successfully the blood
ylobules circulating in q vein.