Evening journal., 1904-05-04


single Hair From an EyeIash VIII
Act on the sensitive Mechanism.
Accuracy OF Their weights.
So sensitive are the modern chem
lists and jewelers. balances that not
merely can they weigh accurately a
quarter inch long human hair. but re-
cord as well the differences In weight
between any number OF such pieces
taken from the heads OF different per
sons. And so absolutely correct are
these scales that the same samples OF
hair weighed on a number OF balances
will show identical differences.
With balance Of this sort it Is possl-
BILE to weigh the innnitesimal quantity
OF ink required to write your sigma
ture. All that is necessary Is to weigh
the piece Of blank paper. then to write
your name on It and to weigh the pa
per again, taking the difference be.
tween the two weights as that OF the
ink.
Down in Maiden lane, in the great
jewel district. n scale expert was talk
ing Of these things the other day.
Within glass fronted closets lining his
Office were scores upon scores OF bal
ances, inclosed IN glass and mahogany
framed cases.
"Delicate?" s;Id the expert, repeat
ing n question. 1--WE have jewellers
scales here that will weigh 500 carats
Of diamonds and will remain sensitive
to the inconceivrbly slight weight Of
one fve-hundredghs OF n carat. The
moisture Of your Sreath against one OF
the pans Of this ccale would throw Il
out Of adjustment Touching one end
OF the beam With finger tip for ten
seconds is enough TO lengthen the
beam. II would expand under the
warmth Of the alnd sufficiently to
throw the needle pointer OF the center.
But, from an experts viewpoint,
these scales are not the most remarka.
BILE. Il is easy enough to make light
scale sensitive beyond oil requirements
Of practical purposes. II Is when we
turn out a scale that can weigh
heavier loads and still remain sensi-
tive that we feel we have accomplish
ed something. Here, FOR instance, Is
scale that VIII hold 5000 ounces in
each pan and that VIII indicate the ad-
dition of rs slight a weight as two
grains. And here Is another that viii
balance 800 ounces IN each pan and
at the same time indlcste the differ
ence between the weishts OF two
pieces OF paper.
"These are some OF tho tests that put
American manufactured balances and
scales 10 the front and that account
for these instruments tsing exported
20 England and throughout Europe. to
South America. 70 Me-.co, TO India
and to Australia. All over the world,
wherever science and the gold miner
have penetrated, we send our scales"
Wherein do the American made bal
ances excelT was asked.
/ Chiefly In wear and in composition
Of a very important alloy, which, like
the pendulum OF many clocks, is what
Is called 'compensating. Bring q
French or q German balance 20 this
country, and It will act like an import
cd plano and many another musical In
strument The balance works excel
lently while in Its home country. but
it is not adapted to the variations Of
climate. moisture, heat and cold that
must be anticipated when manufactur.
ing these instruments TO be sent all
over the world.
"Who are our customers? Every
chemist, every physicist, every as.
sayer and jeweler. Scientific colleges
and the, technical institutions use
scores on scores OF balances. Then
there are the miners and the smelters,
the silversmiths, the steel and copper
and lead and tin men. not to mention
dozens upon dozens OF others, includ-
ing the government departments, the
geological survey, the agricultural de
partment, the medical supply depart
ments Of the army and navy, the mint
and the assay Office.
"Many balances are made especially
to withstand the strains peculiar TO the
particular work for which they are In
tended. Ordinarily a balance consists
Of a slim arm Of brass provided at the
middle with a steel knife edge that
rests on higly polished plane OF
agate attached TO the top Of an upright
brass pillar. stirrups OF the scnle pans
being similarly suspended But in a
chemical balance. where the fumes OF
acids would attack steel, agate knife
edges are substituted.
with ordinary care and regular at
tention a good balance ought TO last q
mans lifetime. We had a balance to
repair not long ago that had been In
constant use for more than forty
years.
LAS much care is expended on the
weights rs is given TO the scales. Mos,
Of the heavier weights are turned out
OF bars Of brass and covered with a
lacquer thst makes them practically
impervious TO attack by moisture OF
fumes Of acids The lighter weights
consist Of platinum foil. which is even
more durable than brass. providing the
thin. tiny pieces are handled with ordi
nary attention and care Still. despite
all precautions. the weights will 'fal
or and for accurate work 1t is neces
sary to test them from time to time.
"The diamond expert about to sal
abroad for the markets OF London and
Paris, for example. usually buys a
brand new set OF weights before he
quits these shores. Some OF the ex
pcrts buy a new balance every trip tc
make sure they are getting an instru