Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1907-04-06
[tyNE*cie!n!!;ce |
|NsifveSStion|

A new type Of vacuum tube for use
In x.ray experiments has Just been
brought out in Germany. An aluminium
"film" IL placed inside the tube, and II
II claimed that this serves to absorb all
the rays emanating from the anticath.
ode, which are not true Roentgen rays,
and which by striking the glass walls
are responsible for the heating effects
and chemical changes that gradually
change the character Of an ordinary
vacuum tube.
A new alloy. called McAdamite metal,
has recently been put on the market,
with the idea that 1t may largely take
the place Of brass in machine-making.
Its base 10 aluminium, but the exact
composition Ii kept secret. 1t resem.
bles aluminium only In lightness and
non-corrosiveness 1t has about one.
third the weight Of brass, but about
twice the tensile strength, and Its re-
sIstance to compression IL nearly four
times that Of brass. 1t takes a high
polish, and does not tarnish. 1t Is W.
norous. and bells are now made Of II.
The Chinese have long been credited
with the invention Of g,inpowder, but
Prof. r. o. Won Lippmann Of Halle has
collected evidence to indicate that this
II a mistake and that the Arabians did
not. ms commonly stated. introduce gun.
powder into Europe during the eighth
and ninth centuries. Prof. Won Lipp.
mann believes that the manufacture Of
the first gunpOwder was based upon the
"Fire.book" OF Marcus Graecus. which
appeared in COnstantlnople about the
middle Of the thirteenth century. This
was the source from which Roger Ba.
con, Albertus Magnus and Thomas
| Aquinas derived their knowledge Of
gunpOwder. The first use of ginpow.
der to drive proJectiles Is ascribed to a
monk. Berthold Schwartz. whose discov.
cry was made accidentally while pre-.
pairing the mixture for medicinal pur.
poses.
| What the drop of water does to the
hardest stone Is only a circumstance to
what thread of yarn can accomplish
A warden of federal prison once found
a prisoner who was supposed to he
pounding stone. working away ut one
Of the bars to an outside window. The
man finally admitted what he was do
Ing and was induced to give a demon
stration. A grating of the same descrlp
ton was placed In his cell and guart
stationed over him to exact the proof
Of the statement. When the limestone
dust and sillcate from the stone pile
the yarn from his sock aud a littl'
water. this man cut the bcsscmcr stee
bar In eighteen working hours. Will
some fine emery. a chalk line and TIVE
wooden handholds to save his fingers III
made tho other clean cut Of the bar II
five hours. proving the matter TO til,
guards satisfaction.
Almost everybody knows the rule o
the masons that stone used In building
should be 10 placed that It will lie as !
lay In Its natural bed when Quarriet
But Francis W. lIoyt. In the Engineer
Ing News. says that this familiar rule
not always to bc depended upon an
needs In many cases to be supplement
eli with other precautions. There ar
three planes Of fracture known to quar-
rymen. The rift" Is the direction 4
which the stone splits most easily; tn
grain" that which II next easiest; I'll
"head" that which offers the creates
resistance. In a paving block the Nv
sides represent the rift fracture, I'll
top and bottom the grain AMI the end
the head. But In a quarry the natur'
bed Is sometimes considerably incline
to the plane Of the rift; hence the In
perfection Of the ordinary rule for pla,
Ing the stone In building.