Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1897-11-18
Notes on science nnd industry.

potassium cyanidc certain ahhouh% Va
cyanide OF mercury. the best results pc
ing obtained when the solvent contains
O.O5 per cent. of potassium cyanide ana
0.oa5 per cent. cyanide Of mercury. This
mixture OF the cyanides. IL is claimed,
operates more speedily than the simple
potassium cyanide. For the recovery OF
the gold from this solution. the process
Is an electrolytic one. The gold ana the
mercury are deposited together upon
amalgamated copper plates, the ANAL
gam so deposited Is scraped on, ana the
gold recovered by distilling or the mer-
curry in the usual way. the anooe Is
not allowed to dip In the cyanide soiu-
ton. but Is placed in separate COM
partment and surrounded with a solution
of an alkaline salt, and In this way the
cvanide does not become decomposed.
The electro motive force OF the current
need not be more than half voit, anu
the current density on the deposi'ins
surface NAV be as low as 0.0S ampere per
square foot.
The driving of light carriages by means
of liquefed carbonic acid as motive
power has been often proposed, the an
ficulty chiefly encountered being the great
absorption of heat, and consequently loss
of efficiency through the refrigeration vi
the engine. as the liquid expands ana re-
turns TO the gaseous state. Inc latest
method brought forward for avoiding
this difficulty Is due TO the ingenuity OF
q French inventor NJ. Rassimier, MS
metbod being to press the carbonic acid
through capillary tubes In cnaniper
heated to 2is degrees Fahrenheit by petro-
leum or coal briquettes, the heated gas
being then admitted TO the engine GYM
der. where II acts upon the piston, anu
is then led into chamber or jacket sur
rounding the liquefied gas. the gaseous
acid giving up the necessary neat 10
change the liquid acid to the gaseous
form OF 30 degrees c., pressure or 10
atmospheres IL finally developed. Inc
final exhaust of the gas takes place from
the Jacket or chamber me statemeh'
is. i'm substance, that the capillary heater
insures the first expansion OF the gas
while the addition of pressure through
the heating of the reservoir by the ex-
haust gas takes place only when the en-
CINE is working.
Tho committee of the American Boiler
makers Association on standard specifi-
cations recommends an established ois-
tinction hereafter between shell steel ana
hange steel. According to this new rule'
shell steel not exposed to the direct neat
Of the fire or gases of cobustion may
have from 5000 to 10000 pounds tensile
strength, with an elastic limit or half It's
ultimate strength: shell plates which are
| exposed to the fire or gases of consump-
| ,ion or on which any Hanging Is TO De
done. to have from GO, 900 to 5000 pounds
tensile strength, with an elastic limit
half the ultimate strength; plates lor
fre-boxes, such as are exposed 10 the
direct action of the fire and Hanged on
the greater portion OF their periphery
| to have 5000 TO 5000 pounds tensile
strength, with an elastic limit haif the
ultimate strength. In regard to elonga'
t,on the committee discards any dis.
tinction I'm respect to thickness, and
makes the elongation "a per cent. fol
shell plates of the highest tensile
strength above given. q per cent. fol
those of medium tensile strength, anc
| 40 ner cent. for fire-box and fiange plates
all on 3 inches For rivets the use u
recommended as essential OF eithe
good charcoal iron, or sort miId stee
having the same physical and chemica
prouertIes as the fire-box plates.
Engineering skill is likely to play
nent Russian port and terminus OF IN
siberian railway, but where Tor over lou
months the port is blocked up with ICE
rendering shipping traffic impossible. Fo
many Years the Russian authorities nav
been endeavoring TO overcome tnese ma
tural difficulties, and some time ago Ice
brea king ships were introduced to brea
omen the ice, an operation, however
which has proved practically useless.
is now reported that "a certain engineer
has proposed plan for retaining IN
narrowest part OF the Tartar strait DC
tween Saghalien and the Russian man
land. The theory Of such an undertaken
Is that II this Is done. the colo currei
which enters the Japan Sea from "a
Arctic via Bering Strait will be checked
and the passage of the warmer tius, coii
inc from the south through the Tshum
strait will make the water on the coas
az Japan as warm as Vladiyostock, an
the latter will be warm all the yea
,round The expectation Is entertaine
, that this remarkable engineering wor
! will be entered upon after the compl'
ton of the Siberian railway.
Not so many improvements nave en-
I racterized the process OF coating clo'
| with RUBBER as nave hioi hSN wv -
. of some other features in the applica.is
of that material in the arts. Inc I'm
: solvents used in dissolving the rubber u
: coating purposes are naphtha, shale spir'
and benzol. these being mixed with pui
o fed solid paraffin by grinding togethe
$ Solubility is promoted by grinding
working: the raw or washed ruDoer Is ie
soluble than that masticated or groun
and well-ground rubber is more easl
taken I'D than that which has been ie
worked. The washed rubber Is Tor wa.e
: nroofng. says the Boston commerce
Rulletin. The next operation IL 10 grh
u the rubber and pigments together, run
!, out into a thin sheet, and digest In nap
u tha with a slight stirring as II Is auue
md the finishing is performed by doug
,oivers The treatment OF fabric wni
has 10 be done by spreading with the ~
her consists in passing 1t through ~
NJ calenders. in order 10 press down MI.
Z and give a smooth and even surface ar
e which Il Is passed over steam chest
Q exnel moisture. IL being now ready 10 !
e ceive the first coat. little oxide Oh ~
e or little naphtha. which Is retained
{ the rubber and which 1t gives up '.
e slowly. is a drying which proves gu
n useful and prevents blistering In cui'ns