SUBSTANCE | IMPURITIES | TESTS.
| POSSIBLY PRESENT. |
------------------+---------------------+----------------------------------
Ammonia, | Carbonic acid | Renders lime-water milky.
NH_{3} | |
Molec. Wt. 17 | Dissolved solid | Residue left on evaporation.
| matter |
| |
| Chlorides | After acidulating with nitric acid,
| | it gives a precipitate with silver
| | nitrate, which after washing is
| | readily soluble in ammonia and
| | reprecipitated by nitric acid.
| |
| Sulphates | After acidulating with nitric acid,
| | it gives a precipitate with
| | barium nitrate.
| |
| Lime | A white precipitate with oxalate
| | of ammonium.
| |
| Lead is often | Black precipitate with sulphureted
| present, derived | hydrogen.
| from the action |
| upon flint glass |
| bottles |
| |
Nitric acid. | Traces of | After dilution it gives a
H, NO_{3} | sulphuric acid | precipitate with barium nitrate.
Molec. Wt. 63 | |
| Chlorides | After dilution it gives a
| | precipitate with silver nitrate.
| |
| Peroxide of nitrogen| The acid is yellow.
| |
| Iodine may be | After dilution and cooling it gives
| present if the acid | a blue color with starch, paste,
| be prepared from | or mucilage.
| sodium nitrate |
| |
Hydrochloric | Free chlorine | Liberates iodine from solution
acid, HCl | | of potassium iodide. See also
Molec. Wt. 36.5 | | "Chlorides," nitric acid.
| |
| Sulphuric acid | As above for nitric acid.
| |
| Perchloride of iron | Yellow color. Brown precipitate
| | with ammonia added till it
| | smells slightly.
| |
Sulphuric acid, | Bisulphate of | Residue on evaporation.
H_{2}SO_{4} | potassium |
Molec. Wt. 98 | |
| Sulphate of lead | Milkiness on dilution. May be
| | completely freed from lead by
| | diluting with three or four times
| | as much water, and allowing
| | to settle.
| |
Acetic acid | Water | Does not solidify when cooled
(glacial), | | to 17° C. (53º F.)
H C_{2}H_{3}O_{2} | |
Molec. Wt. 60 | Sulphurous and | White precipitates with silver
| hydrochloric | nitrate.
| acids |
| |
| Aldehyde, or | Blackens in the light after adding
| volatile tarry | silver nitrate.
| matter |
| |
| Organic sulphuric | Smell of garlic.
| acid |
| |
Citric acid, | Tartaric acid | Strong solution of potassium.
H_{3}C_{6} | | Acetate added to a strong solution
H_{5}O_{7}H_{2}O | | of the acid will deposit white
Molec. Wt. 210 | | crystalline bitartrate.
| |
Pyrogallic acid | Metagallic acid | Black residue, insoluble in water.
(C_{6}H_{3})HO_{3}| |
Molec. Wt. 126 | |
| |
Silver nitrate, | Free nitric acid | Reddens litmus paper. (Neutral
AgNO_{3} | | silver nitrate does not
Molec. Wt. 170 | | affect litmus.)
| |
Potassium | Chlorides and | Same as for ammonia.
carbonate | sulphates |
K_{2}CO_{3} | |
Molec. Wt. 138 | |
| |
Potassium | Potassium carbonate| A strong solution is alkaline to
iodide, KI | | test paper.
Molec. Wt. 166 | |
| Sulphates and | Same as for ammonia.
| chlorides |
| |
| Potassium iodate | A pretty strong solution becomes
| | yellow from liberation of iodine
| | on addition of dilute sulphuric
| | acid or, better, a strong solution
| | of citric acid.
| |
Potassium | Similar to | See potassium iodide.
bromide, KBr | potassium iodide |
Molec. Wt. 119 | |
| |
Sodium carbonate, | Chlorides and | Same as for ammonia.
Na_{2}CO_{3} | sulphates |
Molec. Wt. 106 | |
| |
Sodium chloride, | Chloride of calcium | Oxalate of ammonium (after
NaCl | Chloride of | addition of a little acetic acid)
Molec. Wt. 58.5 | magnesium | gives a milkiness, or precipitate,
| | indicating calcium; filter this
| | out and add ammonia, chloride of
| | ammonium, and phosphate of sodium
| | (clear solutions). A precipitate
| | indicates magnesium. Both the above
| | cause dampness in wet weather.
| |
| Sodium sulphate | As for "sulphates" in ammonia.
| |
Potassium | Potassium carbonate | Effervescence with dilute acids,
cyanide, KCN | nearly always | giving off a gas carbonic
Molec. Wt. 65, | present | anhydride, which renders
and hydrate, KHO | | lime-water turbid.
Molec. Wt. 56 | |
Kaolin | Chalk | Effervescence with dilute acids.
| |
Water, | Sulphates and | Same as for ammonia.
H_{2}O | chlorides |
Molec. Wt. 18 | |
| Calcium carbonate, | Deposited by boiling. Test as
| temporary hardness | for calcium chloride. See
| | sodium chloride.
| |
| Ammonia, almost | Brown coloration, or
| always present in | precipitate with Nessler's
| distilled and rain | reagent.
| water |
| |
Gelatine | Alum | Ash, sometimes as much as ten
| | per cent.
| |
| Fatty matter | Separated by precipitation with
| | alcohol. Dissolved out by ether
| | or benzine, and left as a residue
| | on evaporation of the solvent.
| |
| |
Ammonium bromide | Potassium bro- | Leaves a residue when heated.
(NH_{4})Br | mide or other |
Molec. Wt. 98 | non-volatile |
| bodies |
| |
| Ammonium chloride | Same as for chlorides in
| | ammonia.
| |
Pyrogallic acid | Powdered glass | Left behind on solution.
| |
Potassium iodide | Potassium bromide | The crystals of bromide are
| | usually more transparent than
| | those of iodide, but no reliance
| | can be placed on this.
| |
Silver nitrate | Potassium nitrate, | Will not yield the full quantity
| sometimes present | of chloride on precipitation
| in the fused | with HCl. Gives a purple color to
| sticks--not in | flame.
| the crystals |
| |
Sulphuric acid | When vended as pure,| No easy test can be given, as the
| it invariably | substances are so numerous some of
| contains a trace of | them volatile, and most require
| iron. Common acid is| separation from the acid before
| also liable to | detection.
| contain arsenic, |
| selenium, thalium, |
| and many other |
| substances. |
| |
| Organic matter, as | Gives a brown color to the acid.
| a piece of straw |
| in a carboy of acid |
| |
Hydrochloric acid | Arsenic | Marsh's test.
| |
| Some yellow samples | Reinsh's test; a small piece of
| contain no iron, | copper foil becomes coated
| but an organic salt,| on boiling in dilute acid.
| and give an alkaline|
| ash on ignition of |
| the residue after |
| evaporation |
| |
Calcium chloride | Calcium hydrate | The clear filtered solution made
| | with distilled water is alkaline
| | to test paper, and gives a
| | precipitate on breathing into it
| | through a tube.
| |
Pure (?) chemicals| Broken glass, bits | These impurities either float or
generally | of straw, wood, | sink on solution, and may easily
| paper, etc. | be seen.
-------------------------------------------------------------------------
G.M. JONES, M.P.S.
* * * * *
THE CATASTROPHE AT CHANCELADE.
The Chancelade quarries near Perigneux, which caved in Oct. 22, 1885,
under circumstances that are still fresh in the minds of all, have
gained a celebrity that renders it unnecessary for us to revert to the
details of the catastrophe. It will suffice to recall the fact that
after the accident a private committee was formed for the purpose of
making an attempt to save the five victims who had been surprised in
the drifts, and who happened to be in the bottom levels.
[Illustration: FIG. 1.--PHOTOGRAPHIC EXPLORING APPARATUS.]
The Lippmann establishment at once offered to make a boring by means
of which it would be possible to communicate with the galleries in
which the men were imprisoned, but, despite the most active efforts,
success was found impossible. In order to satisfy public opinion, the
committee resolved to bore a well 12 inches in diameter to a depth of
23 feet, that should permit of reaching the gallery; but this did not
render the latter accessible. How was it to be seen what had occurred,
how was it to be made certain that the men were dead, and that all
hope of rescue must be abandoned? To Mr. Langlois, a Parisian
photographer, was confided an order to construct a special apparatus
which might be let down to the bottom of the well by a cord, and
which, being capable of operating from a distance, should furnish the
required information through sensitized plates. As may be seen, this
operation presented peculiar difficulties, although Mr. Langlois was
enabled to overcome these with much skill.
The photographic apparatus that the ingenious operator constructed was
contained in a metallic case that could be let down into the bore
hole. The upper and lower parts of the contrivance were provided with
incandescent lamps, that could be lighted or extinguished from a
distance, by means of conductors. The photographic apparatus, properly
so called, formed of an objective and camera with its sensitized
plate, was inclosed in a cylinder 3½ inches in diameter. By means of a
cord drawn at the mouth of the well, the apparatus could be made to
issue from its vertical sheath, and to pivot around its axis so as
take views in different directions (Fig. 1).
The entire affair was suspended by twelve-foot iron rods, connected
with each other end for end.
In using the apparatus, the operating was done in a shanty, which
served as a dark room. The device was let down into the bore well
until it touched bottom. At this moment a cord was pulled so as to
raise the camera, and then a few moments were allowed to elapse in
order that the apparatus might become immovable. As the objective was
all the time in the dark, it had neither cap nor shutter, but was
unmasked from the beginning of the operation.
In order to form an impression on the plate, it was only necessary to
give light; this being easily done by passing an electric current by
means of a commutator, so as to light the incandescent lamps. At the
end of the exposure, the lamps were extinguished and the entire
apparatus was immersed in darkness. The mean time of exposure was from
four to five minutes. The apparatus was then hauled up, and the
negative developed.
The experiments could be renewed as often as necessary, and the
apparatus be pointed in all directions by turning it a certain number
of degrees by means of a lever attached to the upper rod. In this way
were obtained various views of the inaccessible gallery in different
planes.
[Illustration: FIGS. 2 AND 3.--REPRODUCTION OF PHOTOGRAPHS TAKEN IN
THE INACCESSIBLE GALLERIES.]
We reproduce herewith two of Mr. Langlois' most interesting
photographs. One of these shows the head of the corpse of a young
miner whose face stands out in relief against the side of the gallery
(Fig. 2) the other shows a wheel and a lot of debris heaped up
pell-mell (Fig. 3).
The series of proofs obtained from small negatives, two inches square,
gave the completest sort of information in regard to the aspect of the
subterranean gallery.
The exact place where the boring had been done and the entire and
broken pillars were recognized, as was also the presence of two
corpses, thus showing that it was indeed here that it would have been
necessary to act in order to render aid to the unfortunates.
[Illustration: FIG. 4.--FAULT THAT CAUSED THE ACCIDENT.]
In Fig. 4 is shown the appearance of the great fault that caused the
accident at Chancelade. It seems to us that this method of
photographing inaccessible subterranean galleries ought to receive
numerous applications in the future.--_La Nature._
* * * * *
SOMZEE'S NEW GAS-BURNERS.
With the object of effecting a very intimate mixture of gas and air,
and of causing this mixture to reach the point of ignition at as high
a temperature as possible, M. Leon Somzee, of Brussels, has designed
several new forms of gas burner, which we now proceed to describe and
illustrate, from particulars and by drawings kindly supplied by an
esteemed Brussels correspondent.
The high-power burner shown in Fig. 1 effects perfect combustion of
the heated mixture of air and gas, which is introduced by the draught
determined by the arrangement. What chiefly distinguishes this burner
from others of its class is the fact that it is perfectly suited to
domestic lighting--that is to say, it may be arranged for a
comparatively small consumption of gas, while giving an increase of
250 per cent. of light.
[Illustration: FIG. 1. and FIG. 2. INCANDESCENT AND HIGH-POWER
BURNERS.]
The burner proper is a cage or basket of specially prepared magnesia,
which yields a warmer tone of light than any obtained hitherto, while
not requiring so high a temperature before combustion. The cap, made
of a fire-resisting substance, fits on to a tubular arrangement, R,
fixed in the upper portion of the body of the burner. The latter is
supplied by air entering at the cone, O, which terminates the inner
chamber, K, of the heater, and also by that drawn in by the rising
column of gas, passing before the orifices, D, which may be regulated
at will. The small burner, I, which is kept constantly alight, heats
the central compartment, K, the sides of which transmit heat to the
gas circulating in the annular casing, L, of the compartment. The
heated gas passes, by the passage, AA¹, into the space, C, where it
becomes intimately mixed with the air entering at OP, and also with
the outer air arriving by the lateral apertures, D.
The _vis viva_ of the jet is diffused through this mixture, which thus
becomes very intimate, when it penetrates into the tubular
arrangement, R; combustion now taking place at the top, while the
refractory cap emits a bright orange light of great steadiness. As it
is not the flow of gas which determines the entrance of the outer air,
the former may be used at any pressure--an advantageous arrangement in
all respects.
When the small burner, I, in the lower chamber is lighted, the
products of combustion issue by the orifice, O, of the compartment,
terminating in a needle like that of the steam injector; and the jet
draws along the air entering the apertures, PP, above the cone. The
gas from the pipe, arriving from the annular space, L, fills the two
lateral pockets shown in dotted lines, and passes through the
orifices, AA¹, which communicate with the upper chamber of the
burner. The manner in which it is conveyed thence to the tubular
arrangement has already been described.
Fig. 2 shows a more simple method of carrying out the same principle,
and of effecting a considerable saving in gas for a given intensity of
light. In this form, a wick, T, impregnated with an alkaline earthy
solution, a few seconds after lighting, affords a focus of white light
remarkable for its steadiness and brilliancy. A draught of air is
created by a jet of gas issuing from the hollow needle, B, and passing
through the vessel, D, which is provided with orifices, O, for the
entrance of air. The air and gas pass from D into C, whence (after
their intimate mixture is effected) they pass into the tubular
arrangement, F, at the top of which combustion takes place.
To regulate the proportions in which the air and gas should mingle, in
order that the combination should be as intimate as possible, the air
inlet is made variable by a perforated collar, which permits of the
orifices, O, being more or less covered. The other proportions of the
burner--that is to say, the relative capacity of the two compartments
and the length of the hollow needle--are determined by the sectional
area of the supply-pipe for the gas, which is admitted under moderate
pressure. Instead of a wire-gauze cap, impregnated with a solution of
metals or of salts, two fine platinum wires may be used--one bent into
the form of a semicircle of about an inch radius, and the other (of
slightly larger diameter) rolled spirally round the former. When both
ends of the two wires are connected with the upper portion of the
tubular arrangement (which in this case is flattened), and the gas is
ignited at the burner, the metallic arc becomes red hot, and then
brightly incandescent, emitting a light, less brilliant indeed than
with magnesia, but of remarkable steadiness.
In this case the production of light is chiefly due to the fact that
calorific condensation, caused by the use of the helicoidal coil
surrounding the curved wire, prevents loss of heat in this conductor.
In these forms of high-power burner, in which the gas is used directly
for the production of light, the difficulty generally encountered of
heating the air (present in a larger volume than the gas) has been
successfully overcome.
Fig. 3 shows the straight and outspread flame burner with a special
heater. In this arrangement the gas and air are heated before
combustion, in the compartment, G, directly exposed to the action of a
small Bunsen burner, R, which is placed (in an opaque glass) in the
middle of a lyre-shaped figure formed by the two gas-pipes, AA. The
burner proper consists of two fine annular passages meeting above, and
emitting a thin annular sheet of gas over the guide, T, made of a
white refractory substance placed between the two annular jets. The
object of this guide is to stretch the incandescent sheet of flame,
composed of several jets, and interpose friction, so as to prevent a
too rapid ascent of hot gases.
[Illustration: FIG. 3 and FIG. 4 REGENERATIVE BURNERS WITH INVERTED
FLAMES.]
The luminous focus is placed within a glass globe, C, mounted on the
bell, B, of the heater; and the external air enters this bell,
mingling with the products of combustion of the heating burner, R. The
portion, D, of the annular passage, B, being made of a highly
conductive metal, the gas becomes heated in passing to the burner, so
that both gas and air are raised to the same temperature by the time
they reach the orifices of the burner. Instead of prolonging the
gas-pipe to the point of bifurcation, a chamber may be arranged
immediately below the guide, for the gas and air to become intimately
mixed by passing through several perforations or wire gauze, receiving
the excess of heat from the white porcelain guide. The admission of
gas to both the main and heating burners is regulated by a double
valve in the pipe; but this arrangement may be used without any
previous heating of the gas and air.
Fig. 4 shows a similar arrangement to that above described, but
reversed; the gas and air being previously heated by the products of
combustion. The two pipes, D, lead the gas to the burner; and the
incandescent sheet of flame is drawn over a white refractory
substance, having in its center an orifice through which the hot gases
rise to the upper portion of the burner. The luminous sheet is spread
out all the better on account of this return of the flames, which also
causes the mixture of air and gas to be more complete than when they
rise directly. The gas escapes horizontally from the orifices of the
annular burner, B, and mingles with the double current of hot air
which rushes in above the flame inside the globe, and also below
through the central portion of the burner.
This lamp throws its light vertically downward; and its illuminating
power may be increased by providing, above the incandescent sheet, a
reflector, which diverts into a useful direction the rays thrown
toward the ceiling. In this arrangement of lamp the flame is
excessively condensed by its being turned back over the refractory
guide; and this condensation greatly favors the production of light.
On the other hand, the combustion of the gas is very perfect, because
the currents of hot air are thrown directly upon the two sides of the
flame; and thus the reciprocal action becomes more intense. Lastly,
the division of the gas into a large number of small jets, in contact
with which the hot air forms an intimate mixture, causes a greater
quantity of molecules to partake in the combinations; thus affording a
proportionate increase of temperature in a given space and time.
[Illustration: FIG. 5. REGENERATIVE BURNER WITH FLAME DEFLECTED
OUTWARD.]
Owing to these various circumstances, the final effective duty of this
burner is advantageous, so that it yields an illuminating power which
may be put at from 200 to 250 per cent. above that of ordinary
burners, and about 25 per cent. more than that of other regenerative
burners. The flame is comparatively steady; the loss due to the
friction over the white porcelain being almost eliminated, because the
flame only presses upon the guide for a small portion of its surface,
and is only spread out to the extent of its dark zone.
The contact between the incandescent sheet of flame and the guide may
be made as short as desired, and the motion of the gaseous mass be
directed by a simple button placed in the center of the burner; thus
giving the form shown by Fig. 5, which, however, differs from the
previous figure in the fact that the inverted flame is directed
outward instead of inward.
In this arrangement the button, T, is fixed in the middle of the
burner, which is made cylindrical and annular, or may consist of a
ring of small tubes, to which the gas is led by a single pipe; leaving
the whole "furnace" free for the circulation of air and the products
of combustion. This is the most recent development of the principle
patented by M. Somzee in 1882, viz., the formation of an illuminating
sheet of flame, spread out laterally, while heating the gas and air by
the products of combustion.
Figs. 6 and 7 show two forms of burner designed especially to give
economical results with a small consumption of gas. The former is an
ordinary Argand burner in which hot air is introduced into the upper
portion of the flame, so as to increase the activity of combustion.
The luminous sheet of flame is then spread out by a metal disk
attached to the end of the tube, D, which introduces the air into the
flame. The outer air becomes heated in its passage through the wire
gauze, T, which absorbs the heat liberated in the interior of the
apparatus, and also that which is radiated from the incandescent sheet
and reflected by a metal shield, P, surrounding the dark part of the
flame.
[Illustration: FIG. 6. FIG. 7. TYPES OF ECONOMICAL BURNERS.]
It is the combustion of gas, without the production of useful luminous
effect inside the shield, which supplies the reflected as well as
radiated heat to the air. The temperature is still further increased
by the heat transmitted to the metal portion of the burner, and
absorbed by the wire gauze, between the close meshes of which the air
from outside is forced to circulate. Air is admitted inside the flame
by the chimney, D, placed above the focus, and in which it is raised
to a high temperature by friction on the upper part of the lamp glass,
at E, and afterward by its passage through the horizontal portion of
the bent tube. This tube is impinged upon on the outside by the
flames, and also by the products of combustion, so that it forms a
veritable heater of the currents which traverse it.
The introduction of hot air into the central portion of the sheet of
flame is advantageously supplemented by the spreading out of the flame
by means of the metal disk, without any possibility of its being
divided. In this way a more intense heat is obtained, and consequently
the illuminating power is considerably increased, by the uncombined
carbon being more readily set free, and being thus kept longer in the
flame, F. This burner, which may be constructed for a moderate gas
consumption, gives remarkable results as regards illuminating power
and steadiness; the abstraction of heat in no way impairing the
luminosity of the flame, which preserves all its brightness.
The Argand burner with double chimney, shown in Fig. 7, is also an
economical one for a small consumption of gas. The air admitted to
both the inside and the outside is raised to a high temperature by
passing along the spirals of a second and transparent chimney, C¹,
which surrounds the cylindrical glass, C. The gas itself is heated by
passing through this hot chamber before reaching the outlet orifices;
so that the mixture of air and gas takes place under the most
favorable conditions for their perfect combustion.
The burner is an ordinary Argand, which may terminate below in a small
chamber for the gas and air to mingle. But this is not necessary; and
the usual arrangement for mixing the air and gas may be adopted. The
outer air enters at the top of the central chimney, C and passes into
the annular space between the two glasses; then descends by the two
spiral passages, which surround the cylindrical glass and terminate
in a portion hermetically sealed by a brass plate attached to the
supply-pipe. All the parts of the burner are thus surrounded by a
highly-heated atmosphere, especially at the bottom of the double
chimney; and it will be readily understood that, if the branches which
lead the gas to the burner are constructed of a highly conductive
metal, the gas will become heated in its turn by passing through
passages raised to a high temperature.
The elements are therefore dissociated or separated before their final
combination; thereby raising the calorific and luminous effect to the
highest possible degree. Such a burner can, of course, be made as
small as may be required; thus lending itself admirably to the
subdivision of illumination. The only precaution required is to
properly proportion the sectional area of the hot-air passages to the
radiant surface of the flame, so that the heat does not become too
intense at the lower portion of the burner.
Fig. 8 shows a double flame burner on the principle of Mr. Heron's,
but with admission of hot air into the angle formed by the flames. As
exemplified by Mr. Heron, if two equal batswing burners separately
give a certain amount of light, on the two flames being brought into
contact, so as to form a single flame, the luminosity is considerably
increased, owing to the condensation of heat which results from their
meeting. The two incandescent sheets are, as it were, forced into one
another, so as to be combined.
[Illustration: FIG. 8. DOUBLE FLAT-FLAME BURNER]