The Cincinnati daily star. [volume] ([Cincinnati, Ohio]) 1875-1880, 1878-04-30
SCIENTIFIC.

consists essentially of claw guide and a
set of vertical and horizontal stretching
and cleaning rolls, over which the wire is
drawn TO be cleaned of scales on all sides.
The wire is then passed through box
filed with mixture of calves hair and
sand.
AN improved percussion fuse for proiec-
| tiles is among the recent German inven-
tions. 1t consists of bolt casing with
suitable retaining base plate and printing
device, in connection with sliding needle
bolt that is retained during the fight of
the projectile by base pins, and forced into
the priming the instant resistance is offered
to the projectile. frangible lead pin Sc
cures the needle bolt to the casing, to-
gether with detachable safety wire that
holds the needle bolt in position and pre-
vents any danger of premature explosion
until it is withdrawn. The fuse is set into
each prepared projectile, the safety wire
being passed through the bolt casing and
needle bolt, and bent over at one end, SO
that the safety wire cannot drop out; the
latter supports the frangible lead pin, and
affords full security during transportation
Before setting the projectile into the gun,
the wire is simply drawn out, the projectile
being in this way made ready for use.
A LEIPsIc journal states that the remark
able success attending the novel system of
river navigation, introduced for nearly the
whole length of the El5e river, of towing
boats by the aid of chain submerged in
he channel, has led to its introduction
upon all the tributaries of that river. BY
the former methods of towing, the necessi-
ty for the reduction of the resistance to o
minimum led to the building of boats of
large size, regardless of the disadvantages
connected with them, such as the greater
difficulty of obtaining full freight from
point to point, uncertainty of running at all
stages of water &c. But, besides the re-
duction of the size of boats, allowed by
this system, it is regarded as probable that
it will be found applicable in cases where
the current has been found too strong to
render navigation convenient or practicable
by the old method-since a boat towing
by means of firmly anchored chain passing
over it is much more nearly independent of
the current, as o matter of course.
The effect produced on the resistance to
ships motion by the lengthening or
shortening of the flat middle body between
the bow and the stern, has recently been
experimentally illustrated in an interesting
manner, by means of models having the
same ends, but different lengths of parallel
body inserted amid6hips. By separating
the effect of the fractional skin, resistance,
| which was proportional to the wetted sur
face, it is shown that the increase or dimin-
ution of the power required to propel a
ship, in consequence of the alteration of
the length of the parallel body, depends
very largely on the coincidence, or want of
coincidence, of the wave crests travelling
alongside the ship with the points at which
the reduction of breadth by the fine lines
begins When this diminution coincided
with wave-crest there was no loss but
rather gain of speed. while, when it coin,
cided with wave hollow, the loss of speed
or increase of resistance, was consider
able.
In paper presented before the British
Association of Science, Prof. Bucknam
gives few facts not generally known,
relative to some of the tessellated Roman
pavements, the discovery of which, some
time ago, attracted SO much attention.
The materials of the Roman pavementa
are, 1t appears of two kinds, one being
derived from the rocks of the district, and
the other composed of clay, glass, &c
the former or natural tessel@ being altered
by chemical manipulation in various ways,
and the artificial consist of shades Of red
and black. In an examination of one OF
these pavemcnts, a floral medallion appears,
and which, on first being uncovered, haG
a verdigris-green headdress and flowers
but, as this was unsatisfactory in chromatit
arrangement, further investigation wal
made, and, on scraping away the surface
a beautiful ruby glass exhibited itself
Singular enough, an analysis showed tha
the change from ruby to green was due tc
the fact that the ruby glass had derived
its color from peroxide Of copper, and tina
the tesselle had become covered will
carbonate of copper from decomposition
Of their surfaces
The experiments made in Germany t.
test the operation of the Westinghouse
railway brake, have perhaps been NOR,
thorough and reliable than those made il
any other country-the point kept in viev
in these experiments being that it was no
SO important to know how quickly or il
how short distance train could b.
brought to full stop, as in how little dis
tanca ifs momentum could raa1lv ba co fo