The sun. [volume] (New York [N.Y.]) 1833-1916, 1891-12-27
NOTES ON SCIENCE AND IsDrsran

The question as to the fatigue OF metals
under long-continued stress has recently been
tested, and. it Is believed satisfactorily sot.
tied. in the treatment Of two similar suspen-
sion bridge links and tho results obtained A
square iron link. twelve inches wide. ono inch
thick. and about twelve feet long. was taken
from q bridge at Kieff. Russia then abo,t
forty ycars old. and tested agails, a similar
link which had lain unused in store ever since
tho building OF the bridge, Under these cir
cumstances. tho means OF comparison were
onsidcred in tho highest degree IA
vorable. and tho result necessarily Of
q reliable character in determining
whether or not iron actually loses. and
to wnat S ssptco any ho Of Ss It. Of strength
FOR the Cd at td link an mtmtS ten
p if$5 pei, cent. at the point q fracture il
inch. with an elastic iRi. Of 10 tons. snd az
Si tRs fsd app pear Hiha ha
S sms drenes aeusy SS
served being well with n the ordinary range Of
variability Of similar pieces OF suchsmotaL
An ingenious method OF inclined and hori-
zontal log hauling has been introduced. very
successfully. at the Hudson River paper pulp
| mills The arrangement consists VI an end-
| less detached chain. running in q recess at tho
| bottom Of a trough. having special links with
log teeth evory five feet. and passing over
srrockct wheels whose centres are 700 feet
apart; the head wheel is twenty five feet above
| tho foot wheel. and the head end OF the chain
swings. end can DO raised or lowered by menns
| Of a small winch to suit the depth OF the water.
they they '' como around the foot Wheel. ell are
caught on the teeth OF the, chain and
are DISCHARGED into a horiizontal iog haul.
hSa Hh
sss By Sa sY,ad tSs SosaSn
S nut s S Ss ss'eS ere
the Of fighs or ten d2HbS teams n and as
feet in length. and u 25-horse power engine is
found ample forthe purpose.
The fact has for some time been obs e"vcd
that paper containing wood pulp rapidly be-
comes yellow on exposure to light, this effect
being due to oxidation caused by the more re-
frangible rays. Gaslight is found to be less
active than tho electric because it contains
smaller proportion Of chemical rays To arrive
at more definite conclusions in regard to the
effects thus produced. a German chemist has
paper containing wood pull, IN g room lighted
NJ me-, the ts%perafare never haSins risen
products si t Of combustion. In another expert.
so badly aedSf s IN
powor OF the gas was vsibly affected; These
IN ss
then exposed to the same source Of light. At
pure hose pS.ed in
containing wood pulp had become slightly
yellow.
The practical use Of air as fuel Is declared to
be a fact which has now been demonstrated SO
abundantly as to admit Of no question. and tho
process which is claimed to be the most suo-
cessful in accomplishing this end is neither
complex nor costly. As is well understood BY
all air is mixed with coal gas and with hydro
carbon vapors. and the compound. when
burned. generates much greater heat than IL
the air were absent-so too. q powerful air
blast is great eeonomizer IL smelting and re;
il directed upon an ineandesesnt SUB.
sars carson. eSs any "s Other *h1 nsets;
that can be made to glow. Coal. hydr6ar-
Gnas % but The
strikes the luminous body the utmost inten- |
an Indefinite period by merely. pressing the in
done By slight MANIPULATION Of the surface
brought to incandescence. and with some
matter fh nSoSnr but very to troaSfe inc
One OF the most notable achievements in
the rapidly multiplying applications Of steel
to structural purposes is tho new chimney Of
that material in Chicago. the dimensions as
given being height Of $50 feet. with an out
side diameter OF nine feet five inches who
the steel varies In thickness from five thirty
seconds at the top to three-eighths Of an inch at
the bottom: The lower seventy. five feet OF the
deep rs ne to XIII be sbe
s aTound i and above this is lined with biology
the steel shell; that Is; the Chimney is lined in
rveted. TIE steel shell is carefully projected
weather. by painfne inside e' and aviae out The
weight Of the chimney is spread to the foun-
that Of the y the b S the base
or found L; on which It rests being con-
ed With layer of cement. then two two, layers Of
steel rails In cement and one layer, Of beams.
Chimney IS twelve d6.iach boilers. twenty iess
ney is nine feet iys Inches. While were it con.
sstructed of brick 1t would be sixteen feet six
inches.
Some valuable practical regulations have
recently been published by the English build.
ers OF a high-speed engine said to run salts.
factorily at seven hundred revolutions per
minute and to develop two hundred horse
power. According to this. il the boiler, pres
sure always exceeds seventy pounds. 1t Is
worth while to use a compound engine. and. II
as high as one hundred and fifty pounds
triple expansion engine. II the engine ex.
hausts Into vacuum the corresponding pres
sure will be about ne-fourth lowef-the ex: Il
tent to which the steam may be expanded
with advantage depending upon the boiler
pressure; II the expansion IL carried 10 i
more than. certain number Of vol.
umes 1t is advantageous to divide II
into two stages-that is, TO expand partly in
high pressure or small cylinder or cylinders
and partly In a. low pressure or large cylindeI: |
with still greater expansion. IT is worth while