New-York tribune., 1879-01-18
SCIENCE FOR THE PEOPLE.

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NOVEL DONE PoR AN OBsERvAToRY.-Pro-
fessor Dascum Greene of Troy, Describes IN me ApeT
c, Iouruai Of Science novel method OF covering the
revolving dones of observatories win paper. Inc
dome lust finished for the Rensselaer, Polytechnic
Institute OF Troy is a hemisphere with an outside
diam. ter of 20 feet The framework, which IL OF
wood, consists primarily OF clrcn'hr Hi''' ioiin
ing the base, and two semi-circular arch girderS
set parallel to each other. four feet apart
I'm the clear, and spanning the en're
dome. These are firmly attached to the Sill.
and kent in n vertical position by kneebrdces. The sill
and griers are Of seasoned pine s inches wide oy jig
thick and the latter zach 49 by 3 inches Ihe paper
covering ia made in sixteen equal sections Inc
framework Of each section consists OF three Vertich
ribs Of pine, each 3$ inches wide ana a men 'icN.
The Joints between sections were made wedtherprooi
by inserting double thickness OF heavy cotton CLOTH
saturated with white load paint 4 four-fcet opening
between the arch grders is covered by shutter WHICH
ia also OF paper stretched over WOODEN Hame'
The weight ofthc dome and its ap?urtenances ABOUT
1000 pounds. 1t is supported on SIX elenacn1 1 u",s m
which ron between groOyed IRON tracks, ana can pe
easily regOved by moderate pressure apphed drecS'
without the aid OF machinery
TIE ELECTRIC LIGHT AND PHOTOGRAPHERS.
A contributor The british Journal OF fhotog'0phD
writes: Are photographers aware that the eieeric
light can be produced without either steam OF u sS
engipel Yet such is the case. IL has been found by
by one man, . degree of rapIdlty and power can dc
obtained quite sufficient for utilization in the produc
ton the electric light. large machine requires
~ course a powerful motor but machine OF moderate
power will suffice for the requirements OF the phoO-
grapher who desires 10 make OF It either in the pro-
ducton OF portraits or enllrgcments am aware OF
machine OF this kind having been constructed ny an
amateur uechanicaD. and it answers we'll what bOw
wanted ~ machine Of similar pow thnt cen pc op-
tanned IN the usual OF business mt moderate
price all complete"
EARTHQUAKE IN TIE MISSISSIPPI Valley
At the last meeting of the ST. Louis Academy OF Sciences
Professor Nipher mlde brief report on the earthquake
Of November 1s 1873. The shock Of this earthquake
was elt over az area of fully 10000 square mle''
The region disturbed forms IN cpse, me MAJOR AXIS
OF winch extends from LeavenwOrth, Kan, To Insca-
l0osa Ala, distance of over 600 miles. The minor
axis extends from Clarksvc, Ark. TO point md
way between Cairo. H. aud ~. Louis a distance OF
800 miles The southern boundary of this REGION mas
rot been determined with great accuracy. The region
of grcacs disturbance along tho MississipDi from
Cairo 20 Memphis Here the shocks were universally
felt The walls OF bldlngs could be- seen to move. ana
strong frame buildn2s creaked as when every l3E
strained by heavy wind. ~ lronton thc shocK was
also 50 severe 10 alarm some who H'ed III Drlck
houses. Along the Missouri from GLASGOW to Lex ng-
tom the shock was also severe, awakening many
families. who thought heavy Tnd,stoaam VAS s ~ ~
travelled rapidly down the axis of the clpsc reaching
h.
Little Rock, Ark, the shock was also distinctly fet a-
though not observed at Carksville thirty-tve miles
further up the river.
4 Buried FOREST.-lt has been recently
discovered that oak forest lies buried III the Valley OF
the Fulda ROsenburg, Ilesse Cassel Germany at
depth from six TO nine feet below the surface The
wood Gourshed at "A very remote period. The greater
number OF the trees discovered were In good peserya
ZION but owing the action OF the water through un
numbered ages they have become thoroughly black in
color They have also become very hard and close so
that they would be good material for carving and Orna
mental cabinet work Some Of the trees are OF great
size one taken ont of rravelly portion of the bed
oppOstc village OF Baumbach and since sent TO the
Geological Museum at Berlin, wa. % feet long nearly
feet in diameter near the root and about ~ nChes az
the top Even larger specimens have been found II is
reported that the furniture aud httnGs OF the GcOoS
cal Museum at Mar9uTs are to pc Sde o es hms "e
buried oaks belong 10 species stlll existing orto an
extinct one.
FREEZING MIxTURES.-lt is upon the disap-
Of heat in the passage OF body from the sold
the liquid state SAYS The BoSon JO"ndL Of ChemsfrU
that freezing mixtures" depend The most familiar
of these mixtures is composed of pounded ice
and common salt, II chloride OF ammonium (sal am
moniac Is mixed with the ice and salt II part TO parts
and parts Of the latter respectively, the reduction
temperature is considerably greater and mixture
o, parts OF ice OF salt and OF nitrate OF
ammonia is even more effective refrserant Other
potent freezing mixtures composed ofsDOw q parts
and crystallzcd chloride OF calcium % parts. by which
q reduction OF 500 may be obtained; equal parts OF
nitrate OF ammonia carbonate Of soda and water t57o
parts suphac Of soda and OF hydrochloric acid
$500 parts OF and Of concentrated hydrOchl0
acid $50; and the list might be extended indon
The cooling in all Is the result OF the
absorption OF heat In the change from the sold 10 Inc
liquid state promoted by the chemical ahlnlty OF the
subs employed. In Ike manner refrigeration may
be effected by the rapid evaporation OF volatile llqud
as in the f1miar experiment OF freezing water by the
evaporation Of either under the receiver Of an arpump
| or by the evaporation Of part Of the water itself
accelerated by iis affinity for concentrated suphurc
! acid.
| SPONTANEOUS observation-disclosures Iyn-
dali has communicated TO the British Royal Society the
results Of further observations nfusions boiled
| in TASKS afterward hermetically sealed. lie took with
him to Alps last Summer 100 tube. OF nfusions-50
containing turnip, and so containing cucumber infu
sion. Twenty TASKS broken in transit. The 80
remained peucd, and the 90 were turbid with organ
sms number Of the 50 TASKS had their ends opened
n air In which sawdust had Deen shaken up. and ali
were soon tuTbd. Another set infected by water
Of cascade derived from melting snow, and IN three
| dayS were thlckly charged with organisms Another
set opened in pure air and remained transparent
| These results confirm Professor Tyndalpe previous
| observations
| LITERARY NOTES.