New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1877-09-29
SCIENCE FOR THE PEOPLE.


In reply 10 some inQuirers who ask Tor the
means Of photo1aphng without camera the Following
nav be OF interest At the School OF Mines O"lunoH
Collecc the following method was adonted 10 "ootan
photographic prints Of a map. The design was W"""
on tracing papcr sheets Of unsized paper Were 'heh
apnd first in bath OF solution Of the rcd pruss"'o Oh
,tas ana then dried This has TO he done where the
neht is faint the red prusslate turns to the yellow
rrussiate upon exposure to sunlight The ded shee'
ne covered With the traced drawing, sheet Of glass
laid on at Cor weight. and tie whole affair placed IN
bright sunlight during short time All parts OF inc
prepared paper except those where the lines OF Tue
tracing cat OF the light. VIII thus contain. after eX
posurc the yellow prussiate Of potash The paper Is
now 10 be iaid face downward bath containing the
sesouohlorde of iro Is better not 10 wet the mack OF
the paper la THIS BATH Immediately all the surface eN
ceu the lines the drawing, VIII become OF an intense
blue color. consequence of the formation OF prussia"
blue The lines 90 the drawing viii remain white Inc
,ner needs then 10 he vcrv thoroughly washed prefer
ably hy putting IL under spout, 70 get I'D Of the IN
changed red prssiatc OF potash remaining in the Wte
lines To make this process quite successful II is ne'es
AIRY that little of some organic acid such as ctHo'
should be added 20 the bath OF red prassate aDd tha'
the sesouichiOde bath should he acidhed bN INC ll
iun of sono hydrocalorlc acid None Of these meras
oXpensive as compared with the si''er suns t,r S
are very cheap 10 IS sald tnat tlt ar ~ ns ~ one
sold for this purpose that only require Iho , ny -
hath Perhaps this could be managed WIN me mar
rails above named, # they were gnte pure hv t cr
l,t aud IN an atmosphere free rom iron u'st. it
tlaaIN CulOf OF Nfl.,l4h uitN r"' "a
SS ne red prussate Of potash aud the sesquicnlelHe
Of iron are together IN solution No novelty Is 'Hneu
fer these processes
Professor Bells telephone is meeting with
favor IN England been tricd with success IN some
Of the rnsh mines Tho statement Is made that WI
speedily ind way into all the mines OF Great bFl'a'
The Astor Library has had great and vau-
nbc accessions in almost every branch of literature
Certain aneles formerly existed in different depart
honH
have been car fully and iuJciously filed the beques OF
fhe te VIM 'Asor a-dug materially toward this re-
eut the library being object Of especial care to the
pres mt head OF the Ar family. and under the manage
mont OF most accomplished librarian, aided by an eN-
perienced sah In the scientific departments the aces
tons are most remark bic the departments OF archie
ology ethnoloay pllOl0gy and numsmatics. IN the
latamod branch SIS collection OF valuable works is sad
By competent Judges 20 be wholly UNSURPASSED It's
books modern travel form another Of its remarkably
fun series In the Illustration Of the fine arts the recent
access0ns Of the most rare and costly character n
ending books Of great value to artists, which their
purses cannot attain The recent expenditures amount
10 abou. 100000 Among the more valuable OF INC
newly-puIchased works few may be mentioned here
such a. "Lart Arabe," by Prisse PAynncs text ana
plates in imperial folio; Archaeology IN Span," from
the National Museum OF that country in seven Volumes
"Panyrus Ebers" a fac-simile OF an Egyptian book
34OO years old; Art In the FontHuebeau Palace" by
Pinor; Caste On Persian Monuments me seIles OF
tSaTrs Ipicl be- cited as examples The card catalogue
Iieeness that every book in the library has become
qcecs visitors, and new books ma their
place I'm he catalogue the hour of arrival. great
increase i'm the familiarity ana usefulness Of the library
within a Few months has become apparent The average
humber readers has doubled, and since IT opened
this month latter the August closing as many as
400 volumes have been called for IN a single day
1t is a curious fact that at the time when the
news Of the death Of NJ Leverer reached this country
b. telegraph the foreign journals just at hand by
mail Announcing a decided improvement in his health
Nature stated that re so FAR restored that he cas
pecd TO resume his official duties at the observatory
Az correspondents keep on insisting that they
perceive the moons Of Mars BY means Of mirror. il
may be worth while TO offer some explanation of what
they actually II anybody VIII hang piece OF
black cloth behind win low pane. and then look IT,
standing little aside frOm the front he viii see that il
acts as a mirror II he looks at the reflection of
some bright object such the shade OF lighted lamp
he viii find that there two reflections which probably
overlap another except at their edges. II he holds
In bright hight object such darning needle.
hc may see IN the glass two separate reflections or
imagcs of IT, especially he stands well aside from the
front Of the glass These two images from the two
sides Of the glass both its back and front reflect In the
same way he a svcred looking glass TO oh
str he may get two reflections very bright
from the back sivered surface very faint from
The upper surface Of the glass But this is not all Some
Of light Of the image given by the sivered back VIII
Dc caught before It gets OF the glass by the upper
surface, forming there new image witon the glass
The new image Will be again reflected by the silyered
back AMI TINS time mostly coming through will be seen
by the observer separate image. IL now remains to
he explained why superuous, faint images OF star
look smaller than the bright image In tie case OF an
object sodsn the stars there is no DISK OF measure
sbe Sire seen; the apparent size depends upon the
amount of light Hence the amount Of light Is great
diminished IN the spurious Images, they appear Nery
much smaller bright image. MIR Proctor esti-
mates the newly discovered moons OF Mars having
probably less and certainly not "a greater diameter
ihan ten miles and of only the best telescopes IN
the world can make these little moons perceptlble
Since the phyloxera, which is so destructive to
crane vines has made In California the fact that
IL has fierce insect enemy may be OF interest IN this
country NJ Laliman stated 10 the French Academy Of
Science that lie found the capable Of
devouring ninety five phylOXeras In ten minutes Such
rapidly at meals will recommend the new acquisi-
ton to our Western friends 1t is described as the arya
OF dipterOus insect OF the genus ShS and II Is to DO
ENCOURAGED IN the French vlney ards.
The alleged claim Of NJ. B)relh to share in
the discovery OF the moons Mars to not
exactly moOnshine, but misrepresentation. NJ Faye, in
preferrng claim before the French Academy, made
the queer mistake OF speaking Of the discovery made
by Professor Watson instead Of Professor Asaph Hall
That strange enough but was not the only mistake
OF NJ Pave II seems there is controversy about the
discovery Of the minor panets-No l75-oetween
Professor Watson OF Ann Arbor. Mich, and NJ BOrei,
of harseil!es France Professor Watson the aste
roid two DAYS earlier than NJ Bore, but the latter
the first determine it's character NJ Faye had the
facts about controversy in his mind and got them
unaecountaby entansed with Professor Halls discovery
OF toe OF Mars, perhaps because NJ Borell has
been suooessul since Professor Halls announcement in
seeing ono OF the new satellites. But NJ. Bore makes
no claim to the priority of discovery of the satellite.
TIE whole matter is simrIy the worst OF heero