New-York tribune., 1878-03-02
SCIENCE FOR THE PEOPLE.

some cxuerm MS by Professor Richard Owen, OF Indi
ana State University, upon the force and Grectiono OF cur
rents Of earth magnetism IL should have been stated
thai the continuous current discovered was toward the
northwest The strength Of the underground CURRENTS
varies In these experiments with the amount OF metallic
sur1c, buried (rum which wires lead 10 the g;ly anO
mctcr the lengthf wire the time OF day. the state ol
weather, and ether circumstances The magnetic NE
rd.an OF Bloomington nd is between % and " CAST OF
north The strongest currents yet onnd have been soon
after sunrise, AMI nearly Or quite at right angles TO thal
meridian; e. from eastsoutheast to west-nofthwesl'
lcs. powerful Ows at that time from southeast
t. northwest and st weaker from sOutA-soutii-
cast 10 uOrh-nOw est bat after crossing tie magnetic
meridau the again becomes stronger from the
southeast to the northwest BY about or p III. the
currents modified TO mark several degrees less
of ealyauoneer detection FOR the Grst two directions
mentioned and several degrees detection for the
last two direcons IT, III short, The strength followed
tho apparent course OF the sun Professor owen sH-
grstl tJt day tHcrc may h" use discovered l3'
the constant supply OF force indicated by these earth
c'rrcnis he uES It possible that the continuous cur
rent wcn be fuds rom metal plates above fho GrOh1
Ilct paIes beneath IT. might prove Of service III mas
tcning trt growth Of plnts; as fqr instance II forcns
connected by wires with 4 metallic roof
MEASURING HEIGHTS BY BAROMETER-A
neat and easily recoeccd rule for measuring heights
by means Of the barometer is given in Admiral
Ftzroys treatise. The figures Of course approx
mate. since allowance is made for temperature;
bu, they win uficn where accuracy Is not required,
and thc height 10 ba ctmated does not exceed quarter
Of mile The rule Is TO DIVIDE the difference OF reading
between tlc upper and lower stations by the decimal
OOII Tie result Is The elevation IN Ieet
NEw-JEpsEY's CLAYs.-The report Of The
Geological Survey OF New-Je!scy includes volume
solely devoted 10 the clay deposits. rese, according to
the map furnished occupy strip nearly on line from
South AubOy 10 Trenton, with width narrowing iom
eight five miles. Aitcr reaching the Delaware tHe
wGlh OF the clay the State is much reduced, but ts
sOuthWes, direction Is continuous along ue border be-
tween Now-Jersey and PeEnayyara South d the ci"y'
adjoining and parallel to II, is an GroG % green sahd
mar OF "A width yaIy .ng iIOI twenty to ten miles
stretching southwcst.riy the STATE from candy
Hook on the Atlantic - Saem on the Delaware These
deposits have long been known, hut their value AMI eX
tent have not been recognized til very recent years.
during the Revolutionary war the clay was IN demand
"fulcrs earth 10 cleanse the bucHskin brceches OF
the Soldiers About the beginning Of this century, n
manufacture OF sJOucwdre pottery from this cay was
started hit the industry OF great importance 80
late leI0. IL ls74 the amount OF hfeclly and stone
clay dug annually near South AElboy was esti-
mated at value ot over Si,00000O, and twelve pot
tcries in Trenton, employing 1900 operatives were
turning per year Sl,5O0O worth OF white carthcp
and ,onstonc ware The Geological Report gives Pas-
tcuars respecting tie clay oi each locality and II most
Instances careful ahtsiS AdFlte /, az" t"aG"rrd a.
10 boring fug Ciats ~ iocdtcs not yet productive aud
good hope hod out that such eXumina tlns may prove
profitable. 10 bo No.tu working, the cluy should not
oe over twenty-five let beo" me surface, ana The de-
pOst not less than fifteen feet thick
VALUABLE COLLECTION OF MoTHs-At the
annual meeting Of the Buffalo Society Of Natural
Sciences Professor A. Il. Grote read report, showing
remarkable progress of the Society during the year
Among rs other treasures enumerated is collection 0f
North American lepiioptcrous insects. OF the nucni-
dp there are gathered 2.O7s specimens showing 966
specles: 432 are "arthor,' tvpcs" making altogether
af
II IS under Prof, ssOr Grotc'- Immediate care.
IRRIGATION PRoJECTs IL CALrFoENrA.--rIC-
f,.sor W. Hammond Han recently delivered lecture
irrrat,n, a. san francisco H. pointed ouf grave diff
cunirs that have scarcely yet had flI consideration In
popular projects Tor irrigation works throughout ile
Safe He caicGlacs ta, whore the population Is lefs
than 100 10 tho ,aarc mile, n1icuug lands ior n;icu
tlrl purposes would co, more than he proGdct would
,,y since tie ls5 tho labor pa: thc ground THE
water required There ~ !csst four diverse soils
In the state, that woIlJ consume widely different quan'
titles II water 10 and soils would take many
mo,e year, to hoconc fairly slturat thau otAer l.
lrtriiuc tbs point the lecturer referred set of
cuial r0m the Kern River, whore 300 cubic feet of
water per second only atad 3G4 ~ acre and anocr
instance where scycny--'y ditcies fom the Tui",
Kawcah. kus- Fan Judqrin aud Fresno Rivers fur-
Ls-d lOOGl feet lcr second 70 !rrSate oay 1870
ceres As cubic foot should -riguie 300 acres the lus
named System scarcely doing a tw uitcth Of the
-
reached their maximum oi ai>urpton!hc !hc time ior that
varying from seven - twenty years. 1.r professor
thought that each district si"uh pay for s own rrl-
..iIg y,ks ~ II needed tn-I a,d ,i i4t the stat.
should 40 at present toward the N"rN simply 10
baSe tu Typographical aud hydroafaphc'u sur'ey Of
iih domain.
RIsKING TIE WRATH OF PAIIAs.--It 1ppc1rs
from Il stat,me IN The C'Wty that serious contcs.
bctwccL -crrcch-,ws aud editors. eld.n fatally 20 the
conbuauis one side. f. posshlr even when no orc'-
attic criticism irIscs the bci. Accoi'linc TO this
account tie editors OF the newspaper tocried TO- have
known no less than Eyo instances where tic
screccL.owl Scoops Gso, approached IN twilight
dark day. attacked the intruder the premises
though ten leet from the u'st The attack IS course,
made with the bcat, aud Tie owl draws blood. The
ane TO one ARRAY between the hild OF wisdom and tie
editorial staff is thus briefly narrated The birds
seemed have fca- and pair thaI attacked
this way. were easily Killed vuh II short stick"
RAILROAD SPEED AND ACCDENTs.- ia
nous ans Of GcOs-e stephenson To the Parliament
airy inquiry as what would Dc the consequence II
great increase Of speed upon railways iomanSaS truc
now as when be uttered It, althou. German rrcice-
so~ Herr Schcfer has apparently fund ,a.t
"loss o lfe too brief Tor his satisfaction. and by
elaborate comparison cf statistics and computations
has put the whole matter on Il mathematical basis. lie
concludes that the danger Of accidents life limb
Increases with the square ol the speed OF the train
From this II appears would require vastly higher
speed than IS usually attempted, to donU!c passen-
gers risk falling through unsafe bridge. Tie
chance, og dana-c the railway track the rolling
stock Of the road sI less an ccd by greater rapii
~ u trye, siuca t,y Increase only III proportion to
the cube Of The speed. The latter feature not reas
suiiuC coMuaiisuu; passengers have Cause to wish
tha; tnry were r,.!ius-NtGch.
DECLINE or MANUAL AIRS IN GEEMANr.--A