^ If the tubes which you propose to solder

thedesired curl.

You

then successively soften allparts ofthis curve,

and

gradually twistit in the direction indicated

by

the arrow,pressing the iron rod constantly

upon

the extremity of the curve.

When

the

end A comes

into con-tactwith the

bend C you

solder

them

together at this point, and thus complete the ring.

PI. 2, fig. 27, and pi.3,^fig. 27, exhibit exam-plesof ringsformed

by

thisprocess.

10. SOLDERING.

^

_{If the tubes which}

_you

_{propose to solder}

F

50 THE ART

OFGLASS-BLOWING.

are ofa small diameter, pretty equal in size,

and

have thick sides, it is sufficient, before joining

them

together,to

widen them

equallyat their extremities,

by

agitating a metallic rod withinthem. (PL 1, fig. 17.)

But

if they have thin sides,or are of a large diameter, thebringing oftheir sides into juxta-position is very difficult,

and

the

method

of soldering just indicated

becomes

insufficient.

Inthis case

you

are obligedto seal,

and

sub-sequentlyto pierce, the

two

ends

which you

desire to join. Tlie disposition

which

this ope-ration givestotheir sides very

much

facilitates the soldering.

Finally,

when

the tubes are of a very dif-ferent diameter,

you

must

draw

out the ex-tremity of the largerandcutit

where

the part

drawn

out corresponds in diametertothetube

which

itistobe joined to. PI.

%•

⁹

^and

15, exhibitexamplesof this

mode

of adapting tubesto oneanother.

For

lateral solderings

you must

dispose the tubes in such a

manner

that the sides of the orificeswhich

you

desire to jointogether coin-cide with each other completely.

See

pi. 1, fig. 7.

When

theholes arewellprepared,

you

heat at the

same

time the two parts thatareto be soldered together, and join

them

at the

mo-ment when

they enterinto fusion.

You must push them

slightly together,

and

continue to heat successively all their points of contact

;

whereupon

the two tubes soonuniteperfectly.

As

it isalmostalwaysnecessary,

when ^you

de-OF GLASS-BLOWING.

51

sire thesolderingto beneatly done, or thejoint to be imperceptible, toterminate the operation

by

blowing, it is proper to prepare the ex-treme ends of the tubes before-hand.

That

end of the tube

by

which

you

intendto

blow

should be carefully

drawn

out,provideditbe so large as torender

drawing

out necessary_; andthe otherendof the tube, if large,should be closed with wax, as in pi. 1, fig. 9, or if small, should be sealed at the

lamp

(pi. 1, fig. 15).

When

thepointsof junction are per-fectly softened,

and

completely incorporated with each other,

you

introduce alittleairinto the tube, which produces a swelling at the joint.

As

soon as this has taken place,

you must

gently pull the

two

ends of the joined tube in different directions,

by which means

the swelled portionatthe jointisbrought

down

to the sizeoftheother parts of the tube, sothat the whole surface

becomes

continuous.

The

solderingis thenfinished.

To

solder abulb or a cylinderbetween

two

points, to theextremity of acapillarytube,

you

cut and seal one of the points atashort dis-tance from the bulb (pi.1, fig. 16),

and

atthe nioment

when

this extremity is in fusion

you

pierce it

by

blowingstronglyat the other ex-tremity.

By

this

means

the opening of the reservoir is terminated

by

edges very

much

widened, which facilitates considerablyits be-ing brought into juxta-position with thelittle tube. In order that the ends of the

two

tubes

may

be well incorporated the one with the

52 THE ART

OF GLASS-BLOWING.

other,

you

should

keep

the soldered joint for

some

time in the flame,

and

oughtto

blow

in thetube,pushtheendstogetherand

draw them

asunder, until the protuberance is

no

longer perceptible.

If, after having joined

two

tubes, it should be found that there still exists an open-ing too considerable to be closed

by

simply pushing the two tubes

upon

one another,

you

can close such an opening

by means

of a morselofglass,applied

by

presenting the fused end ofan auxiliary tube.

You

should avoid soldering together

two

differentspecies of glass

—

^{for example,a tube}

of ordinary glass with a tube of flint-glass

;

because these

two

^{species of glass experience} adifferentdegree of contraction

upon

cooling, and, ifjoined together while in afusedstate, are soviolentlypulledfrom oneanotherasthey

become

cool, that the cohesion of the pointot soldering is infallibly overcome,

and

the tube breaks.

You

oughtalso, forasimilarreason, to take care not to accumulate a greater

mass

ofglass in oneplace thaninanother.

Ifthe first operation has notbeen ^sufficient to complete the soldering, the tube

must

be again presentedtothe flame,

and

again pushed togetherat the joint,or

drawn

asunder, or

blown

into, accordingas it

may

appear to be neces-sary. In all cases the solderingis nottruly solid, but inasmuch as the two masses of glass are well incorporated together,

and

pre-sentasurface continuousinallpoints.

The

mineralogical flame (pi. 1_, fig. 1, A'B)

isthat

which

istobe

employed

inpreference to the larger flame,

when yon

desire to effecta

good

joining^: itis sufficient to proportion the size of the flame to the object

you

wish to execute.

THE

ART OF GLASS-BLOWING.

IV

^.

—

Construction of

Chemical and

Philo-sophical Instruments.

When

a person is well acquainted with the fundamental operations which

we

have just described, the preparation ofthe instruments ot which

we

are about to speak canpresent scarcely

any

difficulty. Indeed,

some

of

them

are so extremely simple,

and

are so easy of execution, thatit is sufficient to castaglance

upon

thefigures whichrepresentthem,toseize atoncethe

method

which

must

be followed in their construction.

Of

such instruments

we

shall not stop to give a detailed description, butshallcontent ourselves with piesenting the design.

On

theotherhand, itisofimportance to ob-servethat a certain

number

of instruments are

graduated

or furnishedwithpieces, or

mount-ings, of

which

itis not the object ofour art to teach the construction,

and which demand

a

more

or less extensive

knowledge

of the

In document ^rt of Iag0=l^toU)(ng> (Page 73-79)