Evening star. [volume] (Washington, D.C.) 1854-1972, 1883-12-19
MAKING THERMouErrRs.
some Material and Considerable rron-
bic for Fifteen Cents.
From the New York San.

| From the New York Sun.
"First-class thermometers Tor fr,ee, ,e-.s.-
! called out man. who stood in the lower n,-,
/ Of Broadway with q large basket Of tbcr5sn,,e-
ters in front Of him. Here is a good chance "a
buy perfected register OF atmospheric t.r.,or-
allure for the small sum Of dime and 2 AR
Step forward, gentlemen, and embrace y5.r "a
portunity,"
The thermometers were enclosed n ne,,
japanned tin cases, and the scales were s,y,-.
Plated and marked in black. Same Of N.
tubes held mercury and some held co!oreI s,f,.
hol
81 cannot comprehend how therrnaroa',-s. seal,
oe manufactured Tor that price a taCr.u. ..,1r
,haAtf sad. where can the profit beg Aua
nave no Idea OF tie great trouble ana a
amount ~ time that Il takes 70 make an aeon,
IAie thermometer l know that Thermometers
eau of oouS"t throughout the city anywhere
from Aitrth cents up. and must saw also that
many 81 them are good thermometers Tho,
cheap thermometers are Not manufactured ID,
ms city. They come chiefly from Connecticuf
.,e llefe are several large factories, which
turn them ont in vast numbers"
Why are accurate thermometers SO costly "a
make?" ~ 00'''S "
In the first place, we nuy the glass tubes a-l
test them. According 70 NY cA-.,l-,rlf, orlv
one ont q every six Is ct to .ut into thc..
mometcr." M
"How are the tubes tested"
'B! drawing into them ashort column 81 nor
curry. and measuring its length nj a ir,.r,.,.
points with pair of diyiaers. Il is alsolu,aIv
necessary that the bore of the tubes be uniform
Then the bulb has TO be blown and filled Nth
mercury. The air is driven out Of the tube ~
heating the mercury 70 boiling POINT and thea
putting tip Of sealing wax on the open rrl
The amount OF mercury necessary FOR the tule :
regulated 10y yaporil.lg il OF Then tie gD.1
on ~ 10 fl1l - fsl,t
The next thing is to make the scale"
Must fresh scale be made Tor each tier
momcter:"
Certainly. To make the scale Il Is necessary
to have At least two points On the Dubbed TUE
which holds the mercury. The points usLg..y So
ected are the freezing point ana boiling point
oI water. For tie former the bulb Is surrounded
10y lee, and Tor tie latter il Is placed in my
water. Prom these points the scale T. made.
Zach scale i stamped out by hand Arrryafl
the Dubbed tube is fastened to the Scale. ,yIagl
IS on silyer-plaIed strip Of brass. Il ist.ra
fastened in tin case"
Are the fifteen cent thermometers EaleEa
this way"
Il suppose that they must be. and # Z, -rr
TINS reason that don't see where the yiU.t
comes in!"
"Is there no other way OF grading thermoa-
eter than by putting the bulb in ice and In boil
ing water
YES. The points may be obtained lv nut
ting the bulbs in water. the temrcra,ure II
which is told 10y standard thermometer kelt
especially for that purpose. That method il
often used"
lis mercury better than colorcd alcohol In
thermometers
lit is EXCEPT where the thermometers are
wanted for measuring extreme cold Mercury
can be frozen solid, tut II is Impossible 10 freeze
alcohol Experiments lave been made which
show that the most intense cold known will only
have the effect az making the alcohol uily in It's
appearance. Mercury vii h~fau mann lt,Ys Ia-
fore its boils than alcohol does FOR alcohol bnils
at lower temperature than water. Tie Kind
OF thermometers which have been speaking VI
are those which are most commonly used"