The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1869-05-08
SCIENTIFIC NEWS.

PIsroS SPEED.-Tn German loca motives
the pis on speed varies between Ga and )
inches per second. Though this speed Is
far from the maximum, il is rarely exceed
ed up TO this time
"DouBLs ENDER" locomotive has been
invented. Is has M tender, but carries a
water tank over the boiler, and coal in a
box in the rear OF the furnace. IL has
trucks and oow-catchers at aIIher end, and
runs with equal facility w.th either end
foremost.
THE mechanics OF San Francisco have
turned their attention to the contr.vance Of
earthq waterproof chimAeys for the large
factories. An immense iron smoke stack,
forty feet high, eight feet 10 diameter, has
just been raised upon a sugar refinery, the
roof Of which is sixty feee from the ground.
TOTAL EcLIPsE OF rae Sun N-On August
7th o total eclipse Of the sun will occur.
This will be the most interesting eclipse
that has been witnessed 10 this COUNTRY for
many years, and it will not happen again
until the last year Of the century The
shadows OF earth will commence crossing
the suns disk about -four O'Clock ia the az
teraOon, and will nut entirely pass from n
until nearly half past six.
Ii plate glass be laid over grass-beds no
dew will be deposited underneath the glass
plates, although all around the grass will be
completely wetted. TIE ex planation il that
the glasses, being radiators Of heat, act 10
the same manner Is the clouds, returning
the heat TO the bodies underneath th-m, anu
preventing the formation OK dew thereon
THE best speed for boring cast iron il
about " feet per minute. From 10 to IL
feet per minute 10 good circumferential
speed for tools drIlhng into iron. The Fro
per circumferenital speed for turning iron is
about Is feet per minre.
Seals on boilers lilo inch in thickness
will cause loss of A per cent. of heat. or
in other words "A per cent. more fuel is re-
quired for firing.
SMALL boilers from 30 to 36 inches diam
eter should not have greater length than
from i've TO eight times the diameter.
SIzE.-We clip the fOllo~ing recipe for
making size for manu- ufacturing purposes
from an English journal: "Place in an iron
or copper boiler about thirty eight gallons
OF pure water, and add about eighty pounds
Of salt of soda or other alkaline salt, which
diss0lves By heat and agitation About 900
pounds OF resin Is pnt in small Quantities,
having an interval OF tine between each
addition TO allow OF the resin being thor
ouRhiy dissolved before adding fresh
quantity. After the whole has ben mixed
the heating 10 discontinued. About forty
four pounds of chloride Of ssdium ls melt Cd
In about ffty gallons Of eold water. fha
resin, while still hot, is then mixed together
with half VI the saline water rs above pre-
pared, with about thirty gallons nf cold
water. The mixture is then heated and
stirred With q spntala, 20 as 10 render it ho-
mogeneous, and assumes q deep vine color.
This change 10 produced by the uniun OF the
| prepared re-in and the salt. The msxrars
10 then ailo sed 60 scsls and form IN deposit
. the bstfom of ne vessel, ths liq1Id part
being decsnsed and discharged. The AZ.
! posit 10 then ready Tor nee. - -