Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1895-06-22
sEvENTrEN CROSSED.
Notes on Science and Industry.

| Of engine cring H. N" concrete hriiSe'
! having n clear span Of lGi feet ana - feet
| wide. lately constructed over the
| Danube. so Munderklnccn IN Austria.
| where. as IL appears, stone is scarce AM
costly. while good Portland cement is
produced i'm large quantities. Under these
| circumstances. the plan pursued was TO
| cover the centrng with oiled paper ana
/ on this the concrete was laid. cOnsis>-
/ ing Of one part Of cement. . ~ parts
sand, and of broken stone. all Of
these being thoroughly mixed to-
gether; blocks Of this concrete are
said to have shown resistance Of
some iS7 tons per square foot in seven
| days. 25 tons in twenty-e.ght days.
and sos tons in five months. I'm the case
OF this bridge the method adopted was to
| apply the concrete in layers of twelve
| inches thickness. starting az the abut-
ments and working toward the crown.
| where IL has a thickness IF 3I.2 feet.
| while midway 10 the crown 70 presents
thickness OF il-2 feet. The time spent
in laying the concrete was but nineteen
days after the centres were struck. and
the DETECTION proved less than Az
inches
Some succesef-, trials are reported as
being mode i'm various places with the new
nautical motor, Boy which any boat say
from ten 10 eighteen feet long can be
Transformed into an electric launch. with
ont any alienation. simply by Screwing
90 the stern Of the craft a fitting similar
20 rowlock plate. the motor being At
tachabie at once ana easily. From the
tip of the tiller 20 the screw the equip
mont for this purpose. as EXPLAINED. l.
three and half feet long About eigh-
teen inches Of this length consisting OF
the motor. controlling lover. ana tiller.
are lnboar1 Of the sternpost. that part
which runs outbcarl being simply
nickel-piated 2inci shaft-tubp. the
weight > pounds. and the bat
terry for running being from -
10 2'3 pounds. the weight varying
with the choice Of primary or storage
battery. The 2-biaded screw is Of
10 inches diameter. and. inst FOR
ward Of this on the shaft-tube. there is
located stecring-0n both motor ana
st"ering-eear being thus combined I'm the
same machine By means Of this ar
ranecment from one third 10 one hair
an electric horsepower is developed with
four 4-cell batteries. giving twentv-eix
volts. and, as stated. from three 70 five
miles an hour is the result. according to
load and resistance.
The scientific journals describe q sorios
Of tests lately made to determine the loqs
Of heat from steam-pipes due 10 radiation
three distinct conditions being observe,
IN the calculatiOns-namoly bare mines
pipes covered with inch OF compos!tlon
and pipes overlaid with inch of coppo.
slilon and three surfaces OF hair felt
each half an Inch in thickness Tho
steam pressure used was from A. to 90
pounds, and the results showed that. with
] inch or composition out Of possible
loss Of 100 per cent. S}ia per cent. was
saved and. with the extra felt coverinA
"a per cent. additional marked the saw
ing il is remarked that II a single
pound Of coal is required 10 eyaporate
pounds Of water into steam al Cd mounds
pressure, then Gi5 hundredweieht Of coal
would be needed every year 10 make
good the loss Of heat FOR every SQUARE
foot Of uncovered steam-pipe.
\ German inventor W. Gutwasser. Of
konlgsberg. has devised the following
method Of preparing wood PUN for the
manufacture Of varl-colored ruosalcs in.
tended for floors. The particles Of differ,
ent varieties Of wood are put through IN.
process separatoly. so that the natural
color Of the wood itself is brought into
prominence, and dyes, dissolved in alco-
hol. are mixed with a shellac solution he.
fore the wood particles are coated. these
being first cOlored with dyes. dissolved i'm
water. and allowed 10 drv thoroughly be-
fore the coating with the shellac solu.
tion. For simple floors II sufices that
the mpsaics be manufactured Of different,
colors. changing them Al pleasure. and in
this way forming an assortment Of colors
The production Of pattern or fancy wood
mosaics is proceeded with a. follows.
Pattern moulds Of the required design.
divided into fields and figures. are fitted
into the plain mould. each section Of the
design is filled with the dyed wood pulp
the pattern mould removed. and then the
whole. thus freely outlined. is subjected
10 heat and pressure. the result being
perfect varl-c0lored fancy mosaic. an ar
ticle which. Notwithstanding its hardness
and resisting qualities. still retains all
the well-known essential properties Of
wood.
The significant fact is recorded that the
extraction of heat from melted Stag for
steam-making purposes has been accom-
plished with satisfactory results at es-
adjustments IN New South Wales Aus
tralLa, and 1t is thought that the economi-
cal generation of steam according to this
method Of operation may prove to be Of
practical importance i'm fields Of service
yet untried. The Stag is poured from an
ordinary furnace into tubes set vertically
through n boiler-shell, the diameter Of
the tubes increasing towards the lower end:
the heat passes in this Arrangement
through the tubes TO the surrounding
water, and the solidlhcd contents of the
tubes, together with the skins which form
upon the dumping-pots. are delivered to
a wrought-iron car passing below the
boiler nd the feaI-Wutar 10 faceaT ntyar