New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1878-08-10
SCIENCE FOR THE PEOPLE.


How GLACIAL PERIODS ARE Produced
In a recent work. "The Physical System OF the Unit
verse;" by Sydney skertchley the author gives the fo
lowing as TO the OF glacial and nterglacial
perlods The theory about to elucidate alrms
that when the northern Winter is in apheon at time
when eccentcity is high the northern hemisphere wiz
be glaeiated and the southern hemisphere Do enjoying
an ntergacal climate; but this result brought about
by secondary We will proceed 10 snow hrsp
that glacial period would not result directly rom
these causes and secondly how glacial period Is pro-
duced indirectly The first point can be settled in Few
words quantity of heat received from the sun
during revolution inversely proportional 10 tue
minor axis OF the orbit; and as the difference OF the
minor axis at the periods Of maximum and minimum
eccentricy only 907 to 1000 the quantity remalus
practically the same and have little or no influence
upon climate IL is quite otherwise when we consider
the indirect effects variations OF eccenrcy Taking
the mean distance OF the as 014OO,OOO miles, we
find that when the eccentrcity is az its superior UNIT
OOY775) the apbeon distance Is 9S,5O635O miles, tue
perheon distance 1898 $50 miles, and the difference
consequently, I4,2127O0 miles. The amount Of heat
received by the earth In these two positions Is as ~
to o. Let Winter in the northern hemisphere
happen in apheon when the eccentrcy Is at It's supe
ror limit must have done owing 70 procession tine
earth will then be S6i1 $50 miles further from the sun
In Winter than at present aud the direct neat received
will be one-hth less and during Summer oneAtth more
tnin now. Next, lct MlutcT oCcuI
the eccentricy is at its greatest the earth will then
be IA 2I2 700 miles nearer the In Winter than In
Summer The Winter will then be comparatively warm
and IN our latitude The difference Of temperature between
Winter and Summer will be almost annihilaiel NOW,
as Winter in one hemisphere corresponds with summer
In the other It follows that while hemisphere would
be enduring the extreme OF Summer heat and Winter
cold, tae other would enjoy perpetual summer from
this we gather 1) that the effect OF high eceentroy
with Winter in aphelOn IL 10 induce extremes OF neat
and cold IN that hemisphere, aud TO minimize the differ
ence OF Summer aud Winter temperature In the other
aud 2j that while the phere Il being gacated
the other is passing through an lhsigiaeia ~ i
After further elucdation OF this theory the writer
explanation OF the cause OF inlcrslacal periods. The
ecccntUcity may and. indeed, actually does, remain
thousands OF years during which time the sOstltla
points will many times complete their revolution aud
thus give rise to alternate glacial and iuerglacih
periods in each hemisphere But the theory dOeS more
for even than this. IL gives us the date oi le ga
cia period, which began about 100000 years ago anu
terminated ABOUT $4,000 years since During tEis long
era, glacial and intergaeal periods OF greater or less M
tensity, aernated at intervals Of from 10000 TO 49,
years"
ICFs AND Ice CREAMs.-What are termed
ices simply OF the juices Of fruits sweetened win
sugar syrup and then Frozen like ice IL is stated
that the best ices made by rt cooking the sugar
into the form Of syrup, having strength OF jO'' Inc
fruit juices strained through sieve aud then aod,d
with little water and the whites Of few eggs, to the
urepared syrup The hnal mixture should have con-
sisence Of 22o then frozen in the usual way To
make The best ice cream. The Scientific American,
ia necessary that the should be Of the best qualify
and the utensils which 10 is made must be absolutely
clean With every quart of the cream mix six ounces
hest pulyerzed white sugar very little vanilla bean,
and the white of one egg The latter imparts smooth
ness and decacy TO the that cannot otherwise be
obtained The prepared mixture Is then to be stirred In
the freezer until it is entirely CONCEALED Those who
desire rstrato ices should follow these direc-
tons carefully and avoid the Of starch or other
thickeners Instead Of vanilla rs flavor Tor the creHm
trinng amount OF any desired nayorng syrup rJulce
may be used as strawberry pineapple orange lemon,
How TO MAKE MICROPH0NE.-A CORE
spondent OF The English Mechanic gives the following
simple instructions for making microphone; go to
q toyshop, and buy a child's toy tambourine Take
thin piece Of white pine wood, say In. by lis In
With pair OF scissors cut piece OF thin sheet copper
about L In broad, in long. Keep one end broad cut
the other by taking OF the corners to blunt point
drill hole toward the broad end large enough to take
small brass screw at the other end another hole, but
only large enough TO receive the end OF small copper
wire Place piece Of copper thus shaped In hand
vice. and up TO right angle the pointed end TO the
height of half inch Now take another piece OF cop
per plato the same breadth, little short Of an inch In
length turn end up in the same way Bore hole In
this 10 take brass get piece OF carbon nle II
10 In long q In. broad 2sths deep drill hole through
Il for screw Now place this piece OF carbon across the
larger piece Of copper plate, and screw II hrmy on 70
the board passing Of course, through the plate Take
the other piece OF copper and screw IL to the board at
the other end. Two very small blocks OF wood may
now be cut into which FIX binding screws. With
coagulne fix these at each edge OF the tambournc
and then by the same process fix the board In the centre
with It's two ends toward the binding screws When
thoroughly firm bring thin copper wire twisted into
helix through the hole in the upright aud twisted firm
to that hole Bring the other end round the screw OF
.t,a N
You have thus connection with the carbon plate Take
small file aud cut nick IN the Of the upright
az the end Of the board just deep enoug o. carry
piece OF stout brass wire NobnSSI ts coPPer in tne
with IT, the distance between the two copper plates on
now 10 cur piece OF stout wire which, falling
into the nick shall by another nick IN beI 50 balance
edao Of me carbon This is long story 10 tell OF what
when is siuplc As 10 the effect although
makers aud found them very good, for large field
fly walking ETC.. the tambourne hnd lar the best
the tambOurne was supported on IOur pieces OF OAK
| think IT would Improve IT,"
A SUBSTITUTE FOR GUTTA-P ERCHA.-AccOrd-
ing 10 The Polytechnic RerteU rival TO indarubber and
gutta percha been found in elastic gum which
has been named Balata This Is the milky sap OF the
bully-tree that ourishes on banks of the
and the Amazon 10 South America. The operation OF
winning the gum IL similar ia every respect 10 that en-
pOyed with caoutchOuc and gutapercha. II resembles
guta-percha closely IN its general properties that
much OF It shipped from Guiana and sOd yearly for
gta-percha-although has many points of superior
ity tits taseless gives an agreeable odOr ON being
warmed. may be cut like gutta-percha is tough and
leathery Is remarkably flexible. and far elastic
than gutta-percha It soft, and may be Joined
piece TO piece like guta-percha, about 1909 Fahr hut
requires 270o Fair before melting higher than gutta
percha) 1t is completely soluble in beDzoe and carbon
dsuphde in the cold Turpentino dssOves II with the
m M