Telegram-herald., 1889-06-14
POPULAR SCIENCE.



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srt~r. = prepared ~ e,zssGax ressssiy-
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scarceiy bear tsuchf2s. esSa wtase usacr
sEs l-azsa. A 4edI1csrSs II s1-s consists
u Observing Stl0rla-s ~ s2-ysr II .x2zl6E-z,
sc1ias eaastc ISLash IA fr1s2eat2, snd
Sh@a slscrsesce1ce ceasSs cecAGtsns the
n-k por2os 4ad washing and drylEz tie
gose4r. ikoss were known - B=FtaIlleg's
~ a.aassns silysr. sL2hosgh they are not
rev oossdsred - % true illuminate Of
silver, being slEviy exile Of silver aud an
nsaiA
Ths true illuminate Is formed BY sddiag
Alcohol - wzsxa solation Of acid Iitrase u
sIlver. We give . forGah. for is preg4ra-
tioa - tie principle upoD which surken
rocks are marked oa The mariners cart,
via, as soLasthlng 10 Dc avoided when ex-
perrin sntlag with chemicals IA every day
use. Pour Ols ounce OF alcohol over one
hundred grains OF powdered nitrate Of
silver, aad add al ounce OF nitric sosd.
When the Nitrate assuaes q white, cloudy
aepearsnce, cold water Is added 20 suspend
the eo1Lltlon, and the powder is collected
oa nlter and divided INTO snsll pOrIions
This Is EFugI2tellIs method, but those Of
FOgnes AID Liebig dif-er froUa IL 10 no i'm
pcrtaot respect For example, the latter
cissolves one part Of metallic silver in ten
parts OF nitric acid. ana then pours the SO
lgtlon into tWcnty y-three parts Of alcohol
This is heated 70 the boiling point, and is
set aside % coal, when the illuminate Is de-
pos.ted IN white, lustrous, aclcular crystals.
tie weight OF which, after being washed,
equals that OF the silver originally en-
ployed.
From the foregoing - viii DO seen how
near 10 tho wind photographers may sail
without running foul OF this most deadly
compound, which only few years ago was
stated 20 DO the most dangerous substance
FOR which we are indebted 70 modern chem
istry. IL Is certainty sin the most danger
Gus or those cognate 70 photography, nos
excepting tho icdidc Of nitrogen, q sub
stance which at one tine was recommended
as giving reInarksbls degree OF sen sitive-
ness when employed in photography. To-
deed. in the earlier times, even the ful-
inmates, not only Of silver, but OF the Other
metals, were suggested as being likely %
possess marvellous sensitive-conferring <
properties. Friction OF percussion are
stated as means whereby the explosion OF
Eliminating silver il effected, but such fric-
sion and percussion need be only very sligh,
mdeed--a touch OF a feather and the fall OF q
drop Of water upon the compound have
been known 70 DO r.s mischief.
We have alluded TO iodide Of nitrogen
We feel it 70 be duty 70 refer 70 the fataI
facility with which this substance can be
| formed \ fow crystals of iodine placed In
capsule, with enough ammonia poured
over II 70 effect its soiution-and tha: is all
The compound arising from this simple
mixture Is the deadly ter-io1ide OF nitrogen
Such a mixture he's been recommended anC
Is employed by many, for removing pyrS
stuas from the fingers. When used Alright
IL Is quito harmless, the condition of safety
being found IN there being an excess OF ths
iodine This solution WAS stated by the lats
Rev. j. =. Reede, r. Il. s.. at tha. time
president OF The Royal Microscopic Society
to form "a agent in cisso,ving gold undel
circumstances valuable and interesting L
microscopes. A drop is placed upon
microscopic slide, and bit OF gold leaf Is
laid thereon; this dissolves and forms beau
tiful tree and shrub-like grow,hs Of brigh
gold.
When photographers feel It incumbent or
them TO use iodide of nitrogen, they ough
to take specia. care not to allow is to b,
placed aside whsre it will dry and crystal
re, as IN this form il can not bear to be
vorched. Even the very act OF throwing i
away may lead to its exploding ere IL 10 pro
| jcctcd into the waste.-British Journal o.
photeQraphy.