The sun. [volume] (New York [N.Y.]) 1833-1916, 1896-12-27
VOTES ON SCIENCE AVID INDUSTRY.

In hiG:exhaustive work on the scientific c~onstruo-
tion OF roadways, lately published, Prof. Shaier
OF tho Massachusetts Institute OF Technology eX.
presses the opinion that the materials best adapted for
macadamiEing are, in the order OF their value, trap.
syenite, granite, ebert, non crystalline limestone.
micn snhist, quarts. 1t IL also stated that In France
the Government has graded stones for this pur.
pose "a follows; Trap, 10 to eoi p~orphyry, 10 TO
GOT basait. 10 10 10; q%uartZito, IL to 10; Grcz
q%uartEore. 1e to go; nint. 8 to 10; quartz, 10 to 1s;
serpentine, 19 TO ls; melaphyre. 10 TO IL; diorite.
10 to II: limestone, 8 10 II; granite. 8 to 10; mill
stone grit, o to 10; amphibolite, II TO 10; schist,
Q to 10; mica schtst, o 10 10: pudding stone. Alto 8.
1t is admitted that where trap Is abundant aud
cheap a macadamized road OF this hard AMI dura-
Bile stone is the cheapest and best. According to the
natural resources OF q locality the question is. Of
course, largely TO BIO determined. Thus, in tho
great Southern plain and in tho Mississippi Valley
there are no crystalline rocks within req h, and re-
course must be had.to quantities., limestone, chcrts,
Iron ores, and gravels; quartzito Is very uneven in
value; limestone Ia good, less crystalline and marble.
like, and is used exclusively on the fine turnpIkes of
Kentucky, Tennessee, and parts of Ohio.
Tho aluminium bronsos, now becoming 10 Eenor.
ally introduced. are the alloys OF aluminium and
copper, In which the amo unit OF copper consider.
ably exceeds that VI tho aluminium. Aluminium
containing small quantities OF copper is not dcsig.
natod as aluminium bronze. while copper contain.
IN hO" 10 W ~ poT Conts u uIulnlum u Dr1I-
tie, having no uso in the arts. Tho useful bronzes
are those containing from I TO 12 parts of alumi-
mum. Tho value of these aluminium b-onzes con-
sists in their non-corrosivo properties and in their
strength. In respect OF tho former. they nearly
rival the nobler metals. and in respect of tho lat
ter they surpass iron and compare favorably with
steel. Tho non-corrosive property is not confined
TO any particular mixture, but is characteristic Of
all tho alloys. and is undoubtedly due to the mi
mute MIN of oxide OF aluminium which is formed on
the surface of the metal whom exposed to the air
this MIN, though imperceptible, doubtless pro.
tectfng from corrosion.
In ONO OF the German textile organs various in.
quiries have appeared as TO tho cause OF tho cioggy
feel and righteousness peculiar to :wooren goods
end.the remedy therefor. Director Spenrath, IAN e&-
pert in this line, replies ii at tho difficulty in ques-
tton is due TO the presence OF lime soap, or. posi-
bly, also iron soap, on the nbre. Against these, he
says, treatment with the ordinary washing sub
stances is inerectivo-soap and soda, even with the
addition of. sal ammonia, fullcr's earth, &C., arc
without avail, the forced washing even tending to
make matters worse, as IL damages the goods and
brings only additional insoluble soap on the nbre.
The goods may also get into this condition IL hard
water containing lime or iron has boon used, espe.
cially for rinsing; such water, coming in contact
with soap, forming an inaoluble lime or iron soap
on the nbre. spenrath's preventive for this
drawback, us far ns It can be made TO go, is that Of
adding TO such water, before. being used for rims
ing, a solution OF soda; but II the goods have once
become cloggy, they can only become cleansed by
drawing them through a bath OF diluted muriatic
acid-or II the oolors will not stand this treatment
they are to be drawn through diluted acetic acid,
then rinsed In pure water so as TO remove the acid,
then washed.
Some idea Of the remarkable character OF the
proposed telescope for The great Paris Exposition
OF 1900 may be gained by comparing the stEc of its
ntty-one inch object lens with the most wonderful
l IN ruVrnetA Tbra che NarrA,t 49,
kind now in existence is the Lick, having an OBJ
tect glass OF thirty six inches diameter; the secvnd
largest is at Pulkou'a. Russia. with n glass OF thirty
inches; the third is ut the University of Virginia,
its glass being twenty-six inches; Harvard has the
fourth largest. with a twenty four in CHI glass, and
the NTH in size belongs to Princeton College. The
famous Yerkes telesc ope glass. the latest of the
celebrated productions at Cambridge, Mass. is
rated at forty inches diameter. Andrso, by some
eleven inches, the Paris instrument Il in excess of
a~ll.others, and thus able. It is anticipated. to bring
the moon within one mile OF us. The telescope at
Paris. as planned, VIII be $50 feet long, and so ar
ranged that 900 persons will be able simultaue-
ously TO view the heavens with It. Tho image, It II
explained. Is to be received on a level mirror SOW
enty Ave inches in diameter, and from that reflect
ed on a screen.
Some interesting computations hrre been made
by ". b Grcenlee of Ithaca, N. ". as reported in
the American Geolo0ist. Assuming that the earth is
saturated with water to the depth of one mile, Mr..
Greenlee aimed to ascertain the relative amounts of
its constituent rocks and their respective porosi-
ties. assuming for this purpose a division or tho
earth's surface into two characteriz ltions. VIZ,
that covered with sedimentary rocks and that COW
cred with iEneous and metamorphic rocks. Then,
to determine the relative areas, the United States
and Europe were selected as typical Of the land
surface. The United States was divided In % three
regions, that cast OF the Mississippi River, that be-
tween the Mississippi and Colorado. and that be-
fyaap Cptoratn aud fba pactNc Thu 1rst .ota-
was divided as to the relative amounts In each State
and the results added; tho central region was
bulked as sedimentary rocks. the western region
was designated half sedimentary and half igne.
Gus and metamorphic. tho complete showing be-
Ing that Sl.e per cent. OF the surface OF the United
States is covered with igneous and mctamorphio
rocks. In Europe. each country was separately
divided, and the percentage of the respective sums
taken, this proving TO be 1913 per cent. An aver
age OF all these results, by coincidence, Is 25.5
per cent, or. roughly speaking. three fourths of
tho land surface OF the earth is covered with sedi-
mcntary rocks having au average thickness of
one mile. Difficulty was encountered In ascertain
Ing an average porosity.
The philosophy OF color In light is presented in
an original way by a contributor In knowledge,
with some facts which have a scientific and indus
trial bearing. It is noted that the light from an
cleo. ric nrc. for instance. when seen near AT hand,
has a distiuctively blush color. but this same light,
when viewed from q distance. appears yeilowish
certain OF its rays having been absorbed by the
water vapor in the DIR on its passage to the eye; for
q similar ruason. the sun is now, by some. consid.
cred to be n blue star; his light, which would ap.
pear intensely white and rich In blue rays espe.
ciaily. II IL could be seen bcyond'o our atmosphere,
appears yellowish after IL has passed through that
atmosphere and lost some OF Its most refrangible |
constituent rays. Tho effect OF absorption. In pro.
ducinR color Is seen In the fact that powdered
bodies generally appear white. n fact accounted for
when 1t ia considered that a powder consists OF
particles arranged at all angles. SO that the light
falling upon It meets various surfaces. ana is most.
ly reflected before II has passed below the sur.
face. and thus the white light reaching Il Is not
deprived OF some OF its constituents by selective
absorption. as would be the case II Il penetrated
the substance and.wa- then reflected. In this way
powdered red glass appears white.
Some OF the Eastern cities hnNo lntelY heen inYna.