designed on this principle; but its application to uninclosed burners
was not very satisfactory, because the great cooling down of the inner
surface of the flames by the strong draught of cold air impaired their
illuminating power. To counteract this difficulty, M. Somzee adopts a
heating burner, A, which he places between the two batswing burners,
B, so that the products of combustion rise in the angle made by the
two lighting flames, as shown; thus greatly increasing their
luminosity while maintaining a low consumption of gas.
M. Somzee also raises the illuminating power of an ordinary flat-flame
burner by causing an obscure effluvium to traverse the dark portion of
the flame. The effect of this is to increase the activity of
decomposition in this portion, so that the particles of carbon are the
more readily set free, and remain longer in suspension in the luminous
zone. The obscure effluvium may be determined between two points by
the electric current, or be caused by the heating of an imperfect
conductor by the current; or, again, it may result from a metal
conductor heated by the reactions produced in the middle of the flame,
by separating the cone of matter in ignition. The effect may be
compared with that obtained by the concentration of two sheets of
flame; but in this case the sheets are formed by the constituent parts
of one and the same flame, whence results a more complete utilization
of the elements composing it. This system is, in fact, a
simplification of the arrangement adopted in the double-flame burner
seen in Fig. 8.
Fig. 9 shows a reflecting and regenerative burner with double glass.
The crown, made of metal polished on both sides, has a circular
groove, G, for receiving the end of the central chimney, C, and
presenting an annular aperture by which the products of combustion
enter. The second glass, C¹, is fastened to the collar of the
burner carrier, and does not come into contact with the metal crown;
so as to allow the air to enter from outside for supplying the burner.
The gas enters by the pipe, T, provided with a cock. This pipe is
continued to the top of the apparatus, and there spreads out into the
form of a dome; thus dividing into two compartments the trunconic
chamber, S¹ S², whence the hot gas returns to the body of the burner,
B.
[Illustration: FIG 9. REFLECTING AND REGENERATING BURNER.]
On the burner being lighted from below, the products of combustion
rise in the inner chimney, and enter the heater, which they traverse
through its entire extent, while impinging against the outside of the
gas reservoir, to which they give up a large portion of their heat.
They then pass by the passage, D, into the atmosphere or into a
chimney. The air necessary for combustion enters at the top of the
outer globe, and becomes highly heated in its passage through the
space comprised between the two glasses of the burner. In this way it
reaches the burner, and forms an intimate mixture with the small jets
of gas which compose the flame. The gas, on leaving the supply-pipe,
T, fills one of the compartments, S¹ S², of the heater, and then
returns by the second compartment, and again descends by the casing of
the supply-pipe, having its temperature still further raised by
contact with the internal radiation of the flame.
Under these conditions, all the parts of the burner are supplied by
heated air, and the combustion becomes very active; thus increasing
the intensity of the flame, and consequently that of the light
afforded, while at the same time effecting a saving of 50 per cent. of
gas. This burner may be made of any size, and for consumptions not
exceeding that of an ordinary Argand. In fact, the gas is consumed at
a low pressure, escaping with no greater force than that due to the
heat of the products of combustion. It is sufficiently expanded on
coming into contact with the current of hot air, the activity of which
is regulated by the height of the apparatus, that is to say, by that
of its two chimneys. The mixture is made in such proportion as to
obtain from the gas and air as great a degree of luminosity as
possible. The high temperature of the gas, and the independent means
of heating the air and gas, constitute the essential principles of
this burner.--_Journal of Gas Lighting._
* * * * *
THE CLAMOND GAS BURNER.
[Illustration: THE CLAMOND GAS BURNER.]
In this burner, which is a French invention, the light is produced by
burning ordinary coal gas within a basket of magnesia, which is
thereby brought to a high state of incandescence, and from which a
white, steady light is radiated. It may be said to consist of three
different parts. The first and inner part is a central column, B, of
fireproof material. The second part consists of two concentric
cylinders placed round the inner column and communicating one with the
other through the cross cuts, J. The third part is a china cup
inclosing the other parts, and perforated with a number of holes. The
gas burns in two different places. From A it passes directly through
B, at the top of which it branches off through tubes to an annular
chamber, D, from which it escapes through the openings, _a_, _a_, _a_,
where combustion takes place. The other combustion occurs within the
circular space, G, I, between the column and the inner of the two
surrounding cylinders, through two channels, E E, in the lower part of
the central column. The gas passes into a circular chamber, F F, and
escapes through small holes in the upper partition of this chamber,
where it burns. The product of this combustion passes put into K,
through the cross cuts, J. The air entering through the holes, H L, of
the outer china cup passes along the inner of the two concentric
cylinders, which is heated to redness, and rises highly heated toward
the upper annular burner, where the gas burns at _a_, _a_, _a_, in small
separate flames, each entirely surrounded by the hot air. This insures
perfect combustion of the gas within the basket of magnesia placed
above, and which is thus brought to a state of incandescence. It will
be seen from this description how simple and practical the
arrangement is. It is claimed for the light produced that it will
stand comparison with the electric light. Like that, it shows colors
perfectly true, and will enable an observer to distinguish between the
most delicate shades, allowing of the finest work being executed as by
daylight. It is, moreover, stated to be perfectly steady. As the
Clamond burner can be fixed to any gas bracket or lamp now in use, its
adoption causes no other expense than the cost of the burner itself.
There is no expensive installation, and when used in combination with
the electric light, it is claimed that a uniform lighting will be
obtainable instead of the unpleasant contrast between gas and
electricity. Another important advantage obtained by the Clamond
burner is the saving effected in the consumption of gas as compared
with the same power of light obtained from ordinary burners.
* * * * *
A NEW THERMO-REGULATOR.
In the thermo-regulators which have been constructed heretofore, the
heat has been regulated by the variation in the inflow of gas to the
heating flame. The apparatus described below, and shown in the
accompanying cut, taken from the _Zeitschrift fur Instrumentenkunde_,
operates on an entirely different principle. The distillation and
condensation process of a fluid heated to the boiling point in the
vessel, A, is as follows:
[Illustration]
The steam passes first through the pipes, _a_ and _c_, into the
serpentine tube, where it is condensed, and then flows through the
tubes, _d_ and _b_, back into the vessel, A, if the cock, _r_, is
closed, but if the said cock is open, it flows into the receptacle, K.
When the liquid begins to boil the steam passes freely through the
tubes, _d_ and _b_, part passing through the tube, _f_, out into the
air, and the other part passing through the open cock, _r_, to the
receptacle, K; but the condensed liquid soon closes these passages to
the steam. At _h_ is an opening for a thermometer, _t_, and through
this opening the liquid can be poured into the vessel, A. If the cock,
_r_, is kept closed, the volume of liquid in the vessel, A, cannot be
diminished, and the bath, B, must take the constant and uniform
temperature of the steam in the vessel, A, as the vessel, B, is heated
evenly on all sides.
This apparatus can also be used as an air bath, in which case the
vessel, B, is left empty and closed by a suitable stopper.
* * * * *
PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.
The accompanying engraving represents a simple apparatus, which any
person accustomed to working glass can make for himself, and which
permits of quickly, and with close approximation, estimating the
density of a liquid. In addition, it has the advantage of requiring
but a very small quantity of the liquid.
It consists simply of a straight pipette, A B, to which is affixed
laterally, at the upper part, a small U-shaped water gauge.
The two branches of the gauge, as well as the pipette itself, are
graduated into equal divisions. If need be, the graduating may be done
by simply pasting on the glass strips of paper, upon which a graduated
scale has been drawn. The zero of the pipette's graduation is exactly
at the lower extremity, B. The graduation of the two gauge tubes
extends in both directions from a zero situated near the center. The
zeros of the two branches must correspond as exactly as possible, so
that they shall be in the same horizontal plane when the apparatus is
fixed upon a support. To render the apparatus complete, it only
remains to adapt, at A, a rubber tube provided with a wire clamp, and
terminating in a short glass tube for sucking through with the mouth.
[Illustration: PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.]
For taking the density of a liquid, we plunge the end, B, into it, and
then suck, and afterward close the rubber tube with the clamp. It is
essential that this latter shall hold well, so that the levels may
remain constant.
We now do the reading. Suppose, for example, we read 250.3 mm. on the
pipette, and 147.7 mm. and 152 mm. on the branches of the gauge.
Having these data, we loosen the clamp, and allow the liquid to flow.
On account of capillarity, there remains a drop in B; and of this we
read the height, say 6 mm. A height 250.5 mm - 6 = 244.5 mm. of liquid
raised is, then, balanced by a column of water of 147.5 + 152 = 299
mm.
Now the heights of these two liquids is in the inverse ratio of their
densities:
_d_ 299.5
--- = -----, whence _d_ = 1.22.
1 244.5
We obtain _d_ by a simple division.
When the instrument has been carefully graduated, and has been
constructed by an expert, the accuracy of the first two decimals may
be relied upon. With a little practice in estimating the last drop, we
may, in trying to estimate the density of water, even reach a closer
approximation. In order to measure the height of the drop accurately,
one should read the maximum height to which the liquid rises between
the fall of two drops at the moment when the last ones are falling,
since at that moment, and only at that, can it be ascertained that the
lower level of the bubble is plane. The error in such reading does not
reach half a millimeter, and, as a suitable height of the apparatus
permits of having columns that vary between 13 and 30 centimeters, an
error of this kind is but 1-300. This is the limit of precision of the
method.
The clamp might be advantageously replaced by a glass cock, or, better
still, A might terminate in a rubber bulb; and a lateral tubulure
might be fixed to the pipette, and be closed with a rubber stopper.
This little apparatus is more easily maneuvered than any of those that
have hitherto been devised upon the same principle. It is capable also
of replacing areometers in ordinary determinations, since it permits
of correcting the error in capillarity that is neglected in
instruments; and, moreover, one can, when he desires to, easily verify
for himself the accuracy of the graduation.--_La Nature._
* * * * *
USEFUL BAGS, AND HOW TO MAKE THEM.
By JOHN T. HUMPHREY.
Since the papers on "Boot and Shoemaking," in vol. i. of _Amateur
Work_, illustrated, I think nothing relating to the leather trades has
appeared in it; and as there must be many among the readers of this
magazine who have a desire to dive deeper into the art of manipulating
leather into the various articles of utility made from that material,
I will endeavor in the series of articles of which this is the
commencement to furnish them with the necessary instructions which
will enable them to do for themselves many things which now are left
undone, or else have to be conveyed miles to some town where the
particular business, or something akin to it, is carried on. To the
colonist and those who live in out-of-the-way districts, it must be a
matter of great regret to observe articles of use, where the material
is in good condition, rapidly becoming useless owing to the inability
of the possessor to do the necessary repairs. Again, it may be that
the article is completely worn out, and the old proverb that "a stitch
in time saves nine," will not be advantageously applied if carried
out. In that case a knowledge of making new what we require, whether
in order to replace something already worn out or as an addition to
our store, must prove beneficial to the thrifty amateur. My object in
writing these articles is not to deprive the mechanic of any portion
of his legitimate occupation, but to assist those who live at a
distance too great to be able to employ him, and who necessarily
prefer any makeshift to the inconvenience of sending miles, and being
without for days, an article which might possibly be set right in an
hour or two.
HOW TO MAKE BAGS.
The old-fashioned carpet bag (Fig. 1) is still unsurpassed by any,
where rough wear is the principal thing to be studied. Such a bag, if
constructed of good Brussels carpeting and unquestionable workmanship,
will last a lifetime, provided always that a substantial frame is
used.
[Illustration: FIG 1.--THE CARPET BAG.]
Next in order comes the brief bag (Fig. 2), more extensively used than
any other. For business purposes it is in great favor with bag users,
being made in a variety of shapes, but all belonging to the same
class. Here we have the shallow brief, deep brief, eclipse wide mouth,
imperial wide mouth, excelsior, courier, and many others; but to know
how to make one will be sufficient for all, the only difference being
in the cut or style in which they are constructed.
[Illustration: FIG. 2.--THE BRIEF BAG.]
The cricket bat bag (represented in Fig. 3) is made on the same
principle throughout as the carpet bag.
[Illustration: FIG. 3.--THE CRICKET BAT BAG.]
Frames and all necessary fittings required in making bags may be
purchased of dealers.
Care must be observed in choosing all the pieces necessary for a bag
from the same pattern carpet, otherwise it will present an unsightly
appearance when completed. There may be some who would prefer American
cloth; this is thoroughly waterproof, and has a good appearance for
some time, but, like all articles of imitation, it has only
_cheapness_ to recommend it. If cloth is to be used (I mean American
cloth), let it be the best that can be bought, that which is called
"double-twill duck," if possible. As the making is the same whether
cloth or carpet be used, it will be understood that the instructions
for making apply to both.
The following tools, which are few and inexpensive, will be required:
A pair of clams (Fig. 4), cost 1s. 6d.; knife (Fig. 5), 6d.; half
dozen awl blades, ½d. each; three or four boxwood handles, 1½d. each;
3 foot rule, 1s.; hammer, 1s.; a packet of harness needles, size 4,
cost 2½d. (these have blunt points); a bone (Fig. 6) will also be
required for rubbing the stiffening into place, cost about 3d.; and a
ball each of hemp and wax for making the sewing threads--hemp 2½d.,
wax ½d. For making holes in the bottom where the nails or studs are
fixed, a large sewing-awl will be required; this will probably have to
be bought at a saddler's; the other tools can all be obtained at any
grindery and leather seller's.
[Illustration: FIG. 4--Pair of Clams. FIG. 5--Knife. FIG. 6--Bone
Rubber. FIG. 7--Method of Measuring Registered Frame: A to A, Top of
Sides; A to B, Top of Gussets. FIG. 8--Pattern of Bottom, Showing
Place of Nails. FIG. 9--Side Pattern Folded. FIG. 10--Gusset Pattern
Folded. FIG. 11--Pattern for Gusset Stiffening. FIG. 12--Handle,
Showing Distance of Rings.]
The awl blades mentioned above are of two kinds, and either may be
used for this work. Those generally used are of a straight diagonal
shape, making a perforation the shape of a diamond, <>*; the others are
perfectly round, tapering gradually to a fine point. To fix them in
the boxwood handles, place the blade in a vise, leaving the unpolished
part above the jaws; hold the handle above this, and commence driving
it down, taking care that the blade is penetrating the middle of the
handle. Continue tapping the handle until the ferrule reaches the
polished part of the blade; it will then be in far enough.
* Transcriber's Note: Original diamond vertical instead of horizontal.
A good serviceable pair of clams may be made by taking two staves of a
good-sized barrel, and cutting about 10 inches off the end of each.
Screw together with three screws (as in Fig. 4), and shape the
uppermost ends so that the outsides meet in a sharp ridge along the
top; this will give a flat surface within the mouth, by which a hold
of the work may be obtained. A two-inch screw will be long enough for
the bottom, which must be turned in as tightly as possible; the others
must not be less than 3 inches, as there will be a space of 1½ or two
inches between the staves at the part where they are inserted. Screw
these just tight enough to give a good sharp spring to the mouth of
the clams when they are pressed open; this will insure the work being
held firmly while being sewn. Sandpaper them over to give a smooth
appearance, and these will be found as useful as bought ones.
A piece of basil leather will be required for the bottom and welts of
the bag. This may be purchased at a leather seller's with the tools.
Cut out the bottom first; the welts may be cut from any narrow pieces.
These must be cut seven-eighths of an inch wide, then folded over, and
lightly hammered down. This brings the two edges together, and when
placed in position, they should lie evenly between the edges of the
material. A piece of string may be laid in the welt to give it a
fuller appearance if the leather is very thin.
The following dimensions of bags when made up will enable the maker to
choose the most useful size:
No. 1, 16 by 14 inches; No. 2, 19 by 16 inches;
No. 3, 21 by 17 inches; No. 4, 24 by 18 inches.
The sizes of frames and parts when cut will be as follows:
Frame. Sides. Bottom. Gussets.
No. 1, 15 inches 16½ by 15½ 16½ by 5½ 15½ by 5½
No. 2, 18 inches 19½ by 17½ 19½ by 6 17 by 6
No. 3, 20 inches 21½ by 18½ 21½ by 6½ 18½ by 6½
No. 4, 23 inches 24½ by 19½ 24½ by 6½ 19½ by 6½
Taking No. 1, 16½ inches will be the length of sides and 15½ inches
the depth. The gussets are also 15½ deep, the width being 5½, the same
as the bottom. Take 1½ inches from the depth of these to allow for
covering the frame, and ½ inch from the length to allow for the seams,
and we have a bag 16 inches long by 14 inches deep.
And now to commence. Arrange the pieces of carpet on the board, and
mark off the size of each part required with a piece of chalk or
pipeclay. By cutting with the carpet, laying the right side up, we
shall be able to see that the pattern of it will be in the same
direction on both sides of the bag when made up. We next take the ball
of hemp, and by pushing the finger through the hole in the center of
it, drive out the end. To use the hemp from the inside is much the
best way, because the ball will stand perfectly still, whereas, if
started from the outside, it will be darting in all directions about
the floor of the workroom, and entwining itself around any obstacle
which lies there, unless it is placed securely in a box and drawn out
through a hole in the center of lid.
A hook must be fixed in some convenient place to make the waxends on,
or, as they are called in the trade, "threads," which term it will be
as well to call them by here; thus a _four-cord thread_ means a thread
or waxend containing four strands of hemp, a six-cord contains six
strands, and so on. One of the greatest difficulties for the amateur
is to produce a well-formed thread. He generally finds it thicker a
few inches from the point than at any other part. These are known in
the trade as bull-necked threads; and as the mechanic finds it
difficult to use them when his employer starts a new apprentice and
gives him this job for the men, I must impress on the worker here the
necessity of making them as perfect as possible. It would be as well
if a little practice was given at breaking the hemp in the way which
produces good points. Better waste a few yards of hemp than be
compelled to abandon a thread after making only a few stitches with
it.
Gripe the hemp firmly between the thumb and forefinger of the left
hand, leaving about eight or nine inches hanging loosely down; lay
this over the thigh of the right leg, and with the right hand rub it
in a downward direction, which will cause the twisted strand to
loosen. One good stroke should be sufficient; if not, it must be
repeated until the fibers forming the strand are quite loosened. By
holding it close to the end with the right hand, and giving it a jerk
with the left, the fibers will break, and the ends of the strands
formed in this way are placed at a little distance one above another,
which, when twisted, form a smooth, tapering point.
To cast off a thread the proper way is to stand at a distance of about
three feet from the hook previously mentioned, and by holding the end
of the hemp in the left hand, pass it over the hook and bring it down
with the right, then holding with the left and breaking as above. When
sufficient strands to form the thread have been broken off, carefully
examine the points to see that they taper properly, and have no lumps
in them. Rub the wax up and down a few times, so that the thread may
be properly waxed on that portion which will be inside when twisted.
Hold the two ends in the left hand, and with the right roll each end
separately down the right leg a sufficient number of times to twist
the thread throughout. Judgment will be required in this operation, or
the thread will be a constant source of trouble if it is over-twisted.
Wax it again, and then it is ready for use. See that the points are
well waxed, then take a needle and pass the point of the thread
through the eye until it nearly reaches that part which would stop its
progress.
It must now be turned down on to the thicker portion and carefully
twisted. Smooth it down, then take the other end of thread and another
needle, and fasten it on in the same way. In selecting the awl to be
used, do not take a very large one. The hole should be just large
enough for the thread to require a slight pull to get it through.