The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-02-26
NorEs on sorENcE AZ tNprsrnE.

Cleveland Able. before the American Philosophical
Society, that some observers have seen the enrore
boroAlis light in such positions between themselves
and neiphboring objects as TO demonstrate that the
aurora. like the lightning. may be entirely conhned
to the lowest stratum: others have seen 10 90 located
among the clouds that its origin must be placed 81 OF
below their level, and therefore within q few thoN-
sand feet of tho oarth's surface. On the othnf
hand, those who have calculated the Ait.
tudos Of specific beams by trigonome trlcal
or equivalent methods have deduced heights 81
twenty to a hundred miles. DIR. Boiler haa even
quoted an altitude of I.243 miles. Prof. Able re-
marks that after reviewing tho whole subject since
the time of Ha ] ,y he hnds that all methods agree In
ono fundamental assumption, namely, that the OBJ
served beams and arches have an individual on.
istenco aud n definite locus. an assumption, how.
ever, which is negatived by the euual frequency II
negative and positive parallaxes wherever the par.
allax method is applied. Tho only conclusion a.
sumed as possible lie. therefore, that the Observers
do not SEQ the same object, partly because the
aurora is too low down, and partly because OF optical
illusions.
Additional tests have been made by Or. Russell.
tho London physicist and photographer. In exhibit
ing tho ability Of certain substances 10 photograph
themselves in the dark. Experiments by him with
sundry metals. woods. especially 10 charrod. oilu
and substances containing them. have only cor
hrmed their power to impress an image Of their form
andlines upon a photo graphic plate, II left In con.
tact with 1t or at a little distance In front OF II, in .
dark room, for q longer or shorter time. Various
salts OF uranium, that have been kept under such
conditions for two years. have proved as active
in their effect at the end of that time
as at the beginning. Experiments also at different
temperatures with various substances have shown
that the higher the temperature the more rapid II
the action upon tho plate, so that at an ordinary
temperature, for example, tho words upon o scrsp
of newspaper-the ink containinsa drying o~il-print
themselves logibly in two weeks; att temperature Of
1919 F. the image is clear in hve hours. Vegetable
oils have proved especially active in photographing
themselves.
According to German authority-Gtack Auth
fact that the locust tree attlins in twenty-five to
thirty years the same thickness as the pine in fifty
and the oak in one hundred years. has led TO some
valuable Investigations as to the industrial value Of
this variety of wood: the conviction was particularly
strong on the part Of l.. Kausch that acacia wood
has an important future, especially as regards it's
employment for mining purposes. The same timber
is also found to excel in the propertiea Of hrmneea
and durability, and is, therefore. we'll suited for
many other mechanical uses. such as wheels. bunGa.
ladder step. &c. 1t is well known, of course. that
the treo in question thrives in the poorest soil. even
in the rubbish of stone quarries and slaty declivities.
A watch of remarkable perfection is described in
the London Times. its distinction IT sting on the fact
of its having Just gained the Kew certificate Of 90 Class
A. Especially Good with the extraordinary high
marks of 1871 out of a possible 100. To win the lat
ter a watch would have to be absolutely perfect - .
timekeepcr, q result admitted TO be scarcely within
the range of practical achievement. This watch. an
all English pocket chronometer, has a mean varia-
ton of daily rate amounting to only one-third OF .
second. and tho mean difference between the CT.
IRENE gaining and losing rates to four seconds.
The makers attribute this result to the use of . re-
volving escapement. or tourbillon. a deviceinf which
the frame tn t carries the escapement is made to re-
| Np1xa alnu1y b1t continuously in tha ,ofp frap,A
by the action Of the watch. thus reducing the error
in timekeeping from change of positions piece OF
mechanism which does not materially increase the
complication of the watch. involving in fact the ad-
dition of one wheel only. While the marks of this
watch for temperature compensat on are not claimed
to be unsurpassed-as many as 1877 having been
recorded out of twcnty-those for smallness in va
ration in daily rate and for absence of ~positional
errors are unusually good.
With characteristic thoroughness In the details Of
its various departments. mechanically considered.
the city OF Boston has lately furnished the chief Of
its surveying division with o standard, by meaua of
which the measuring of estates In that metropolis
of somewhat complicated topography may now be
accomplished to the greatest degree of e~xactness.
For absolute correctness no finer one, it Is alleged,
exists anywhere. not even in the Office Of the Coast
Survey q. Washingt IN, which is the repository Of the
United States standards. This improved standard
was constructed in Worcester and conveyed to Bos-
ton on three fiat care. 1t Is 1o2 feet long. and rests
ready for use in n box, the la: placed on brass roll
es set ten feet apart. thus insuring an inanitesimai
amount of friction while expansion and contraction
are going on during the variations in temperature.
The standard is made of drawn steel. as are also the
measuring tapes.
To produce all electric arc light capable of giving
satisfactory practical results iii use under water.
various efforts have been put forth in the past. but
not with the desired success; recently, however.
technical journals report that a submarine arc lamp
of from 1000 to 1000 candle power. brought for
ward by tho well-known manufacturers in this
line, Burdick Il Hall. now meets all require
ments. This lamp is represented to be abso-
lutely watert!ght. with an inner and outer
globe, the upper part of the outer globe being
Theoretically sealed to the metal cylinder containing
the feeding mechanism by means of rubber easkets
and rinRs-the feeding mechanism in this case differ
ing from anything of the ordinary type by being In.
closed in a cylinder both water and air tight. From
the top of the cylinder. through 4 carefully packed
aperture. issue the two insulated wires. which. for
convenience, are bound together into a cable; the
lower portion Of the lamp is protected by an eight
wire guard. Tests of this device at q depth of twenty
Ave feet are said to have proved satisfactory. .
Aline of wire-rope tramway lately completed for
the Plymouth Cordase Company at Plymouth, Mass,
presents some novel features of n specially utllita-
rian character and worthy Of imitation under similar
conditions. This line. of somewfat less than twelve
hundred feet long, will be used for carrying
baled hemp from the warehouse to the mill. At one
point the lines make nearly u right.angle bend,
around which the cars pass without being detached
from the traction rope or manipulated in any way,
thus demonstrating the feasibility Of passing angles
without detaching. The structural work of the line
at Plymouth is of steel. Near the angle station the
line passes over railroad tracks spanned by Q bridge.
Cars of special design for the facilities needed are
employed. aud along the warehouse for q distance OF
600 feet shunt rails extend. SO that the cars can be
loaded at numerous points.
1T is not generally known, except to the initiated
in metallurgical details. that iron chemically pure 10
too soft for mechanical purposes. It ia, In fact.
rarely found in native masses, but mineralizsd in
ores with different elements. metals and substances.
in the form of oxides. chl0rides and huor.des, and.
when reduced TO Il metallic state. these alloy aud
combine; upon such alloys or combinations depends
the commercial value Of the ore. Thus. the miner
allied ores of iron are brought through the
ne tho blaat furnace m tha wall.