The sun., 1894-05-06

Tho use OF brick-dust mortar. as q substi-
tute for hydraulic cement. where the latter
cannot be obtained. Is now recommended on
the best engineering authority, experiments
made with mixtures OF brick dust and quick
lime showing that blocks OF one half inch In
thickness. after immersion in water for four
months. bore without crushing. crumbng or
splitting. pressure OF 1.5O0 pounds per
square inch. 1t is considered. too that the
addition OF even as small proportion as one
tenth as much brick dust as sand to ordinary
mortars ia preventive OF tho dis1nteRration so
often charaeterizing mortsrs used in the
brick dust mixed with lime and sand is
said to be very generally and successfully
practised in the spanish dominions. and is
stated to be In all res poets superior to the best
i!osendale hydraulic cement in ths construc-
even Of roofs whether for setting fiat tiles or
Tor making the usual tropical HAT roof: The
are. approximately. one OF brick dust. one OF
lime. and TWO OF sand, mixed together dry and
tempered with water in tho usual way.
Some new light appears TO have been thrown
by DR.. Knecht on the philosophy and princi-
pies OF dyeing. His conclusions are based on
the oft observed phenomenon that various
color solutions rise with different tIspsed and
TO different light through the medium OF In
serted strips OF filter paper. the difference
being. In fact. SO marked. that a system OF an
u
manner drop OF aqueous solution will spread
or q sheet OF litter paper, forming a blotch.
surrounded by cOlOress halo and the halo
surrounding dot OF magenta was found to
contain about half OF the total hydrochlorio
acid present IN tine dyestuf the fact OF cham-
ica dissertation thus being evident. This
dissolution. says Dr. knecht Is beforehand
attributed 10 IN. chemical action Of the csllu-
lose and in IuNtapOsitipn Is placed the Well-
known fact that solution 81 fannie acid aud
magenta may be- mixed without precipitation,
while tannin- mOrdantet c1tton in the same
hath will at 'nce be charged with a color lake;
further as the phenomenon with the eolorless
halo does not take place with alcoholic nor
water is supposed 10 actually dissoetats dye
haze and mineral acid. but the presence of
celluloss IS required Ia upset the equilibrium
that existed up TO then,
Comparative experiments made with brass
aud phosphor bronze are said to demonstrate
the fact that while the ultimate strength ofths
former Is from $4,000 to ~. .OOU pounds per
square inch. that OF phosphor bronze Is a.. 900
pounds per square inch. As now produced
at the lest establishments. phospOr bronze ts
c0mposed pf alloys Of copper, tin, and phos-
phorus, the TN being mixed with the coDPer
in different proportions according 10 the de-
gree OF hardness or toughness required the
harder metals containing. Of course. the
larger reTceniage OF tin-ths phosphorus be-
Ing aide n clarity oTthCToughlY deOxidizs the
metal As all metal In molten condition con-
taiRs more or less octuded gases. principally
oxygen, and as rho.ghoFus has an enormous
affinity for oxygen. tho chemical action which
takes = ace can be readily understood; and as
those glse5 are tho nrlaripal cause Of weak,
sp,h tae auesL Of Ihs
which are made from hrOnEs properly phOs.
phoTlzed have the advantage o! being sound
ara free from snongine-s possessing also
tensile strength Tar in sNcess OF what ne alloy
would bs had II not been subjected 70 the ph0s-
chorus ueAtEasRL