New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1879-08-16
SCIENCE FOR THE PEOPLE.

been led 70 doubt the elementary nature oil 'nal SUI
s,snce Their governments led them 10 infer that Two
molecules OF chlorine at temperatures ABOVE law
c. break up into three molecules Next cauie 'no qu'
ton-Does this arise from an alteration OF 'no Ho''0
la ,itution OF chlorine or from actual decoinpo-
it,, INTO soma nav gases: I'm other words Is chlorine
an eIerentl ThereupOn the expanded chlorine gas wa"
slowly caused 10 stream into hnid that "osoro' GNU
ripe Potassa lodide OF potassium ana mercury "eio
All used FOR thtpurpose and with the same resu''" $50
accumulated I'm the measuring tube tnst was no' o'"'
rine hut oxygen Chlorine was thereby proven W Oo
not an element but an oxide OF some new elemou'' ~
number OF careful Investigations were then made 10 NC
srre mat the chlorine used absolutely pure anu uIS'
hpr with the same result The element hVpothe'i'
caIlv called Bfuri has not yet been lso.S'ee' Ou' ~
learned professors carrying olt tne luPoi,thhI
Investigation with al 80 i' Hesr more of this
new body That chlorine Is an oxygen compound IL ~
afi"gsthsr n new ides. SIR Humphry Davy tier bis
celebrated discoveries OF the compound nature OF soda
and p0tass surniSed mat chlorine lOdne ana DiVmho
were likewise oxygen compounds
INSTRUMENTS FOR TRAYELLERs.-ln lecture
to the French Geographical Society II. DAbDadie has
discussed The relative merits of the sexant and thoodo
lite As applied to the determination OF the latitude ana
longitude Of places in UNEMPLOYED countries.
DAbbadie insists strongly the disadvantages OF the
sextant The fact that angle OF more than 1lO' can
not be- measured with the sextsnt often makes 1t nm
the tropics. whilst observations by night require mt-
fetal hight which traveller in Wild regions finds 1t
fieut TO procure. Further, IN constructing map
azimuths are required, aud difficult TO Oh
tain with a scxtant that they are rarely taken. NJ
DAbbadic therefore recommends the theOdoiie az Tue
most usea instrument Tor travellers ANA he describes
pattern which he has found very scrYceahe IN THIS
instrument a prism placed ia trout OF The object
S 81 o and gs me- telescope is Away GorIzoa,a
4 a.
4 pounis, ".sIor' Non src -rrS,5cS on to a wooden
triangle. IN determining aZmuths Win tbs instruIch!
NJ. DAbbadie recommends the "elthho"h mttlou u
eqaa. attitudes.
PuOToGRAPHs ~ NATURAL CoLORs.-Cap-
tam Auney the Well-kpoWn EUgHsG photographer. has
succeeded obtaining pcGrcs OF TIE solar spectrum III
Us natural c0lOls, OOth silver plates and on COM
pounds Of silver held in place by ccloUop The photo
graphs are produced by oxidation Of silver COMPOUNDS
when placed in tnc spectrum the colormg matter being
ueapuarcut y 10 a mxtura OF two different sizes 81
molecules Of tie same chemical composition. one o.
which absOrbs the blue end and he otner at the req
end the pecrum ana The sic of the Wo'eene' arc
unaiterablc while exposed 10 the same wavscDsths a.
those b. winch they were produced. C!pain A1ney be-
tie cojors may be preserved unchanged when
r,T,,, sriiSo Inv which Bsrgnetri sonr years agO
obtained photographs rOors, rs produced hF oAi'h
ton ana not due 90 m reference. B'cgntreI5 FhOlo-
gralIt were fugitive; Cmtail Aoney appears 10 nave
with vide ~, TassuiucLtto produce the pictures OF
the specrlu!.
NEW WEATHER THEORY.-Hhe Rev. Henry
Roe FRAs. n Pennington Rec tory. sneIbmue, writes
TO The LOHdgH Times concerning new weather theory.
In MI E9,s opiaioH dry and wet periods succeed one
another iu alternate OF nearly equal length. Not
that thls equality OF duration Qla absolute, or tnst
the wave Of period Is exactly the fac-simile OF that
Of corresponding period at an earlier later time.
NJ md i;fD
The waves 20 make the family likeness csrry discern
ibp. These periods extend over three w"." years iog
each ana tho following simple viii enable anyone
20 work cut The several cycles OF years Tor himself:
L. When the number representing any gwen
year Is even and exactly div-iDie 10y three that
year is The middle or cold and Net Summers.
Q when the number representing the year - ODD aud
uyi,b., Dy Irrc tAru mat year is the middle OF
o. dry ana NOT Summers For example, 1860 is even
and uyi-Die by .rt", and tIe prevailing e-' FIctersuc
OF Iue iee year- 1859 1860 1851 was wet, wet aud
cold: . 1.4lu I-tB g.. oGI .ad Iyi-btr three, and
every body remembers 1862. 1868 aud 1864 as brsI
hos and ury summers. Nr. Roe Goes UOt venture 10
tend these O.Ger places tuan LuEand, but re
shows from observations eAicudins over t%enyaeyen
years that they coincide closely with the weather ie-
cords IN that country
NoRwEGIUM, A NEW Misunderstanding to
Tie Cheo,jeai Netcs nc.ly-dscoyefed metal Norse-
giun has been detected and Isolated by D.. Tcigf
Dahl IN a sample OF copper-nicEc from Krsg TO- III
sljar.aaIden. The color OF the pure metal IS white,
with a SLIGHT browuish cast Whrn polished Il mas pes
&c .tly allie ustGc but aftcf Vine III btcpnes GOV
cred with THU Il m OF oxide II can be hsttencd on,
in au agte mortar 10 hardness it resemble COPPER.
The melting point Is $500 c, ana me specie gravity
g44l rs equlva Ont appears TO be 1873. only one
oxide, 80. has been obtained. wan supHurettcd ny
dro-en gives brown sulp-ide. ven IL strongly acid
hydrOchiJrIc solutions, W.'ca rrf n am n"num
ell pbIde With slight addition OF potassium I,rocI-
anIde II gives brown hui with larger proportion,
green psecp.t4te. The supndng solution Is turned
brown addition oil zinc, aud the metal i depos-
tied in pulyeruleut state To- .ouions Vi THIS metal
are blue. but become grecaIsh IN UI.uuon.
PoIsoN FOR RATS AND MICE.-Carbonate of
barya has Jeeu found te most efficient poison for
rats and similar v,rmn. Indeed. at special series OF
trials the Royal Agricultural College, PrO>kau, Ger
many this substance was found 70 be cilicacIous
than any other. 1t Occur5 as a heavy white powder,
devoid OF taste smell. In the PrOskau experiments
was mixed with four times It's Tcgh; Of hurley meal.
and pellets of tie paste were introduced into
the holes OF the rats, house-mice and held-mlcr.
small quantity proves fatal Il appears to
cause immediate and complete paralysis Of
the hind cxtrcmities, so that IL may he as
sumed that mice eating of tin their holes Will die within
them. II found IN practice that neither fowls Eog
pigeons would touch paste, either in It's soft
when hardened by the sun; that Its employment is
probably free danger the occupants OF tho poul
access 20 the paste heartily Of it aud paid the pen
atty with neiT liyes NIX 10 the carbonste Oi bdryta
paste the Ordinary phosphorus pase proved most de-
s,rUctivc and the fl found by experiment.
attractive the mice soft form tnan wien hardened
pills. But II considerably than the baryta
prepraiou: an imporrat factor IN the cacuetious OF
the farmer who has to wage against rodents an
extensive scale. Carbonate OF DaytH, sprukled sh,
was long ago recommended Dy Kidd to get Ed OF
yagrant cats.
IJVERdRV NOTES