The sun. [volume] (New York [N.Y.]) 1833-1916, 1894-12-16
VOTES ON SCIENCE AVID INDUSTRY.

An important contribution 10 practical en-
cheering and metallurgical science by w. J.
Keep is contained in the published Proceedings
Of the Institution OF Civil Engineers. His in
vestigatlons, carried on for several years, Iced
him TO the conclusion that the proportion Of sui
phur retained by gray cast iron cannot mate
rally iniure. tho iron, except by increase -
shrinERRo, which In tho extreme ends seems ~
be from Q: l0S inch to 9l2i inch per foot. .Ths
most Of the sulphur present in pig Iron
is Lost IL rcmcltins. and that IL is i'm
q ! sulphur is d diminished by Increase mere; Of GarBonS .
free from these elements, u small amount %
sulphur is said to do great harm. and such iron
Further, tho influence OF SULPHUR on ali cak
iron Is To drive out carbon and silicon, TO ln-
strength; but in practice sulphur will not cntef
the iron in tho foundry to n sufficient extent ~
realize these defects.
Much attention is now paid to methods u
1:eproonng the stool skeletons of buildings
erected Mt tho present time, especially in the
case of structures intended for public purposes.
a notable illustration of this feature Ia pre-.
scnted in the treatment OF tho great glrders -
the new fremont Temple In Boston. The steea
girders are first placed in terra Gotta blocks, %
nil sides md below, these blocks being thsn
strapped with iron all around tho girders, ana
upon this Is stretched expanded metal lathinn,
covered with n heavy coat of Windsor comentl
second LAYER OF expanded metal Hath, tho lat
ter. in turn. receiving the finished plaster,
There Is consequently, in this arrangements
for fire protection, first, n dead air space
then q layer OF terra Gotta, a Windsor ce.
finally 'G the %eaier %nY'R Win dsSP c "r sPace fih "ns
great girders are characterized az the vital parts
e ,5e the Ss w9SiS r stssl ,t5HG ss,rs tho s,D,s nSSsS;'Sii - 20 g
fact that a rise In temperature % 5000 would
throw the columns out OF place about an inch
and a half on each side, and "A rise OF about 300
would ruin the steel. Another feature to 30
noted in this work relates to the partitions
these being built of terra Gotta blocks, held
securely In place by means OF angle irons. and
each side, upon which Is placed the plaster.
Quito On ingenious hosting engine FOE
mines is now produced by combining n friction
drum and brake and reversible link motion
hosting engine with ~spirally crooved drum.
1t 10 claimed that in a single shaft all the hoist
ing OF ore, &C., may be done by tho engine in the
usual way, and the empty car or cage or
bucket lowered by means OF the brake, while
for hosting and lowering tho men the drum
may be thrown into gear, and tho engine used
as a reversible engine, handling the load bY
steam; after starting the load the link can b
hooked up. cutting off the steam at
any point OF the stroke desired. thus
doing most of the work by its expansion
in tho cylinders. while In lowering by means
OF the friction drum and brake, the engine docs
feature of this engine is that. while designed
mainly for single shaft work, " can also be used
iion /" i EToo, Tes Spa per% ny srmPiy t and usISs sh e ir,c-
regular reversible link motion engine. hosting
load and cage in one shaft, and at the same time
shaft. The reversing friction and brake levers
are all assembled in n rack in, front of the
engine and operated by means OF thumb atches,
with notched quadrants, so that they will re-
main wherever placed. thus enabling. the en-.
gineer to. operate the engine quickly, safely, and
without fatigue.
Some Of the English photographers are using
zinc plates as substitutes for photographic stones.
The zinc plates. as pure as can be obtained. nrs
passed through highly polished cold rollers to
remove any surface marks, and are then placed
In dilute nitric acid, one part OF the latter to one
hundred parts water: this brings to the surface
OF the zinc q blackish mass containing impuri-
ties. which IL removed by washing with water
peatcd until the nitric acid and water no longer
produces any apprccinble amount of the black
ish mass-such treatment rendering, the plates
absorpttvc and removing all matters deleterious
TO TYPOGRAPHY. They, are now dried, and SUBJ
jected TO the sandblast process, to secure q
they are placed in a bath composed of
four parts Of nitric acid. one Of ,phcs-
phoric acid and 600 OF water, after which thoy
are washed with water; In some cases, when
tine.grained plates are desired. n bath contain
Ing one part of sulphuric acid in 100 parts OF
water Is used instead Of the mixture OF nitric
acid, phosphorlc acid, and water, as the former
plates are washed with a solution OF ono part
alumni to fifty parts water, after which they are
dried and are ready for use: IL Is claimed that
to grease. and OF n similar nature to photographic
stones. They also retain their light color after
being submitted to the above named baths.
In considering the question. sometimes asked.
as TO whether the water from a pond having no
outlet can be used for condensing by circulating
the water over and over again, Mr.. w. q. Kerr.
a practical engineering authority, remarks that
the success Of such q system naturally depends
upon the size OF the pond. both volume and sur
face being factors In the determination OF its
efficiency; that IL. the pond must evidently have
shall remain in 1t the length OF time necessary
for the cooling effect of the total surface
TO abstract the amount of heat which tho
quantity of water received in the opera
ton of condensing the steam. Mr.. Kerr says
that with "A surface condenser the waste by
evaporation would need 10 be supplied. while
with n Jet condenser the extra hot water would
need to be cooled. Again, the exact dimensions
determined in each instance by n very careful
calculation and with due regard to local condi-
tiOns. such as temperature. climate. DC. The
practical points involved in the question at issue
are treated by Mr.. Kerr in n manner that would
seem to be decisive.
An important work has been accomplished ~
Richmond on the Thames. by which it ap-
pears the difficulty is overcome. caused by that
ilHph Nohii o. ppSA Nhab Nv hoOd tiuo
rushes up with great velocity and returns with
equal rapidity-the consequence being that ex-
cept for u few hours in the day. when the tide
Is up, the river channel has been little more
than an unsightly drained ditch of large proper
tons, with a swiftly running stream In its centre.
Recently, however, adam or weir has been built
across the river at Richmond. by which part
OF the tidal water Is TO be retained during each
ebb tide, so as TO keep the bottom of the stream
covered with water at all times: the locks in
this weir are designed for use during the first
half OF the flood and last half of tho
ebb tides only. for at the higher stages
the water passes freely over the weir.
which is then submerged. The centre OF this
dam Is composed Of three sluice gates. which
are hanked on one side by an inclined way, up
which rowboats can he hauled when necessary.
and on the other side by the locks. The method
OF operating this dam. AS described, Is interest,"
ing. Starting, say; at the top Of the flood tide.
the sluice gates will be open. and the tide, as tho
eb5 commences, will be through them in the
usual manner. When the water has fallen be-
tween hye and six feet the sluices will be low
cred and further ebbing OF the tide stopped, tho
gates remaining down until the next Hood tide