Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1893-10-07
POPULAR SCIENCE NOTES.


tute for leather 1t is called "tleXus
fibra," and is derived from flax, suitably
prepared and oiled. 1t has the same APP
pearance as leather. is particularly
supple, and takes a polish eqally we'll
with the best kinds of calf The ma
terial is said to possess great tenacity.
while affording great ease and comfort
to the foot when made into shoes.
Flexus libra, being of vegetable origin,
is calculated also to facilitate free ven,
tilation, and thereby to obviate the dis
comfort arising from what is called
'drawing"the feet.
| THE INTERPRETATION OF FoRCEs.-
Water freezes and becomes ice at 80 de-
grees of Fahrenheit, whereas mercury
freezes at SO degrees below zero of Fab
renheiti olive oil, on the contrary shows
signs of congelation at from 40 to As de-
grees of Fahrenheit. The three sub
stances quoted being all liquids the diff
ference in the loss of heat requisite to
bring them to qualification is very great
indeed. The action of heat on fluids or
solids is equally various. Water boils
at PIP degrees Fahrenheit, lead melts at
6l2 degrees; the fusing point of gold is
2,0l6 degrees, and of iron 1000 degrees.
We give these particulars in order to
show what enormous changes can be eff
fected by cold in the transmutation of
substance from a liquid to solid, or by
heat from solid to liquid state.
Ether boils at &c degrees Fahrenheit, but
has never been frozen by the
severest cold The forces exerted by the
action and reaction of heat and cold are
best exemplifed under the head of steam,
which has only been called forth and
made use of by man since about the
middle of the eighteenth century,
but it has been in action on a
gigantic scale in nature for probably
hundreds of thousands of years, it being
the opinion of many biologists, including
Lyell, that it is the generation Of steam,
whether developed by the internal heat
of the earth in a state of fusion, or
whether by that of the chemical action
of the elements in the bowels of the
earth developing heat, which, acting on
water and thus generating steam is the
great force that throws up such enormous
rocks and masses of lava as Etna has
been doing. The rocks and lava thus
thrown up arein state of fusion by heat !;
but they gradually cool by exposure to
the air and form solid rocks and noun
tains. This action and reaction has been
going on for thousands of years with
little cessation. Heat and cold, again.
cause the oceanic currents on our earth
between the equator and the poles, and
/ MIC nd off 10 90 ri Q
magnetism or polarity, not only on our
globe, but probably all throughout the
universe. This is borne out by the fact
that "the aurora borealis is decidedly an
electrical phenomenon, which takes
place in the highest regions of the atmos-
phere, since it is visible at the same time
at places very distant from each other.
DR.. Faraday con lectures that the electric
equilibrium of the earth is restored by
aurora conveying the electricity from the
poles 10 the equator. ~ Westminster Re-
view.
THE ORDINARY THERMoMETER.-Ord
nary thermometers are generally defec-
tive, says a scientific writer, because OF
slovenly work in making them; The
testing, pointing and sealing 6eing care
lessly done. Tests should only be made
by comparison with a standard thermo
meter, placed with the instrument to be
tested under water. But in the CHEAP
shop the water used is often allowed tC
grow cool, and is then suddenly warmed
by an addition of hot water. The test
ing accordingly is inaccurate. In these
shops also the zero point is determined
simply by placing the bulb in snow, and
; when the mercury has become stationary
. the thumb is placed on the point where
: this is shown and a file makes the mark
The initial point is usually thus mis-
placed from a sixteenth to an eighth o.
! an inch, aud the whole scale is rendered
! wrong. Thermometers with metallic
: plates are sometimes incorrect. Tit
> degrees on them are marked by meant
: of dies, which cause warping o
y curling of tho plates. These have t,
be rolled to tattcn them again, anC
. this causes an increase IN the siz
= both Of the plates aud the degrees
Allowance is sometimes made for this II
making the dies, but the result is usual
= unsatisfactory. A further source OF CT
. ror In this kind Of thermometer come
|, from the fact that most Of them are test
u ed at one point The manufacturer re-
p lies on scale Of degrees that is YER
I. nearly true, and ucs lt for ell iustru
: ments having bulb ot like size. IN
y result Is that tho Thermometers are {
s error at certain points Il 10 Tor fhI
Do reason also that glass Thermometers
i. which have degrees marked upuu Oh
= glass wlih type, AGO apt O. bo lurauoe
Z Tho type used u the same Gee all glass ,
: q almllaf hinN. notwithstanding thlt 81
N huIln may tHIY Ma sits setniH1 thel
mHmeger ara Wual|s tsfsI ls in tha
p arrumas benw Zoos sm HHl ai san
|suftaHIHsn nfWrystfI M tnH.aa
"a thn Is laar tt lho HatsfaHaaf ttiilaa
e haHl Is lhH NHHtf e Ha uhftha' Z
y MnauW IA ttn aHl Namml lalfe.
"a 'trf saH - iha fH.taH H.aa HfilHiH.
|l.uIH.si.f Ne suabI fhaHHE 4
p sa.asf "a 5000, IT ssE