Fanny Fern - "Little Ferns For Fanny's Little Friends"

Archibald Forbes - "The Afghan Wars 1839 42 and 1878 80"

Frank R. Stockton - "A Jolly Fellowship"

Juliana Horatia Ewing - "The Peace Egg and Other tales"

Annual Bibliography of Commonwealth Literature 2007
This paper argues that discourses of love in Ghanaian market literature for youth offer a view into complex negotiations of agency and empowerment. Drawing on Deborah Durham's notion of youth as "social `shifters'" and Francis Nyamnjoh's conception of the "interconnectedness" of agency, I take Ghanaian market literature as one specific case of how African literature for youth foregrounds questions of continuity and change as African societies enter into increasingly complex global relations. In this literature for youth, received notions of love, often constructed out of impressions from American pop and hip hop music, carry new notions of agency that compete with existing "domesticated" forms. Authors like Ike Tandoh and Evelyn Tay employ discourses of love to offer youth alternative avenues for empowerment in a context of socio-economic disenfranchizement. In a creative process of "straddling", this writing both reveals and reproduces the contradictions that obtain in youth configurations of agency.

Acetylene, The Principles Of Its Generation And Use

F >> F. H. Leeds and W. J. Atkinson Butterfield >> Acetylene, The Principles Of Its Generation And Use




_____________________________________________
| | | |
| Temperature. | Coefficient of | Solubility. |
| | Absorption. | |
|______________|________________|_____________|
| | | |
| Degs. C. | | |
| 0 | 1.73 | 0.20 |
| 1 | 1.68 | 0.19 |
| 2 | 1.63 | 0.19 |
| 3 | 1.58 | 0.18 |
| 4 | 1.53 | 0.18 |
| 5 | 1.49 | 0.17 |
| 6 | 1.45 | 0.17 |
| 7 | 1.41 | 0.16 |
| 8 | 1.37 | 0.16 |
| 9 | 1.34 | 0.15 |
| 10 | 1.31 | 0.15 |
| 11 | 1.27 | 0.15 |
| 12 | 1.24 | 0.14 |
| 13 | 1.21 | 0.14 |
| 14 | 1.18 | 0.14 |
| 15 | 1.15 | 0.13 |
| 16 | 1.13 | 0.13 |
| 17 | 1.10 | 0.13 |
| 18 | 1.08 | 0.12 |
| 19 | 1.05 | 0.12 |
| 20 | 1.03 | 0.12 |
| 21 | 1.01 | 0.12 |
| 22 | 0.99 | 0.11 |
| 23 | 0.97 | 0.11 |
| 24 | 0.95 | 0.11 |
| 25 | 0.93 | 0.11 |
| 26 | 0.91 | 0.10 |
| 27 | 0.89 | 0.10 |
| 28 | 0.87 | 0.10 |
| 29 | 0.85 | 0.10 |
| 30 | 0.84 | 0.09 |
|______________|________________|_____________|

Advantage is taken, as explained in Chapter XI., of the high degree of
solubility of acetylene in acetone, to employ a solution of the gas in
that liquid when acetylene is wanted in a portable condition. The
solubility increases very rapidly with the pressure, so that under a
pressure of twelve atmospheres acetone dissolves about 300 times its
original volume of the gas, while the solubility also increases greatly
with a reduction in the temperature, until at -80 deg. C. acetone takes up
2000 times its volume of acetylene under the ordinary atmospheric
pressure. Further details of the valuable qualities of acetone as a
solvent of acetylene are given in Chapter XI., but it may here be
remarked that the successful utilisation of the solvent power of acetone
depends to a very large extent on the absolute freedom from moisture of
both the acetylene and the acetone, so that acetone of 99 per cent.
strength is now used as the solvent.

Turning to the other end of the scale of solubility, the most valuable
liquids for serving as seals of gasholders, &c., are readily discernible.
Far superior to all others is a saturated solution of calcium chloride,
and this should be selected as the confining liquid whenever it is
important to avoid dissolution of acetylene in the liquid as far as may
be. Brine comes next in order of merit for this purpose, but it is
objectionable on account of its corrosive action on metals. Olive oil
should, according to Fuchs and Schiff, be of service where a saline
liquid is undesirable; mineral oil seems useless. Were they concordant,
the figures for milk of lime would be particularly useful, because this
material is naturally the confining liquid in the generating chambers of
carbide-to-water apparatus, and because the temperature of the liquid
rises through the heat evolved during the generation of the gas
(_vide_ Chapters II. and III.). It will be seen that these figures
would afford a means of calculating the maximum possible loss of gas by
dissolution when a known volume of sludge is run off from a carbide-to-
water generator at about any possible temperature.

According to Garelli and Falciola, the depression in the freezing-point of
water caused by the saturation of that liquid with acetylene is 0.08 deg.
C., the corresponding figure for benzene in place of water being 1.40 deg.
C. These figures indicate that 100 parts by weight of water should dissolve
0.1118 part by weight of acetylene at 0 deg. C., and that 100 parts of
benzene should dissolve about 0.687 part of acetylene at 5 deg. C. In other
words, 100 volumes of water at the freezing-point should dissolve 95
volumes of acetylene, and 100 volumes of benzene dissolve some 653
volumes of the gas. The figure calculated for water in this way is lower
than that which might be expected from the direct determinations at other
temperatures already referred to; that for benzene may be compared with
Berthelot's value of 400 volumes at 18 deg. C. Other measurements of the
solubility of acetylene in water at 0 deg. C. have given the figure 0.1162
per cent. by weight.

TOXICITY.--Many experiments have been made to determine to what extent
acetylene exercises a toxic action on animals breathing air containing a
large proportion of it; but they have given somewhat inconclusive
results, owing probably to varying proportions of impurities in the
samples of acetylene used. The sulphuretted hydrogen and phosphine which
are found in acetylene as ordinarily prepared are such powerful toxic
agents that they would always, in cases of "acetylene" poisoning, be
largely instrumental in bringing about the effects observed. Acetylene
_per se_ would appear to have but a small toxic action; for the
principal toxic ingredient in coal-gas is carbon monoxide, which does not
occur in sensible quantity in acetylene as obtained from calcium carbide.
The colour of blood is changed by inhalation of acetylene to a bright
cherry-red, just as in cases of poisoning by carbon monoxide; but this is
due to a more dissolution of the gas in the haemoglobin of the blood, so
that there is much more hope of recovery for a subject of acetylene
poisoning than for one of coal-gas poisoning. Practically the risk of
poisoning by acetylene, after it has been purified by one of the ordinary
means, is _nil_. The toxic action of the impurities of crude
acetylene is discussed in Chapter V.

Acetylene is an "endothermic" compound, as has been mentioned in Chapter
II., where the meaning of the expression endothermic is explained. It has
there been indicated that by reason of its endothermic nature it is
unsafe to have acetylene at either a temperature of 780 deg. C. and upwards,
or at a pressure of two atmospheres absolute, or higher. If that
temperature or that pressure is exceeded, dissociation (_i.e._,
decomposition into its elements), if initiated at any spot, will extend
through the whole mass of acetylene. In this sense, acetylene at or above
780 deg. C., or at two or more atmospheres pressure, is explosive in the
absence of air or oxygen, and it is thereby distinguished from the
majority of other combustible gases, such as the components of coal-gas.
But if, by dilution with another gas, the partial pressure of the
acetylene is reduced, then the mixture may be subjected to a higher
pressure than that of two atmospheres without acquiring explosiveness, as
is fully shown in Chapter XI. Thus it becomes possible safely to compress
mixtures of acetylene and oil-gas or coal-gas, whereas unadmixed
acetylene cannot be safely kept under a pressure of two atmospheres
absolute or more. In a series of experiments carried out by Dupre on
behalf of the British Home Office, and described in the Report on
Explosives for 1897, samples of moist acetylene, free from air, but
apparently not purified by any chemical process, were exposed to the
influence of a bright red-hot wire. When the gas was held in the
containing vessel at the atmospheric pressure then obtaining, viz., 30.34
inches (771 mm.) of mercury, no explosion occurred. When the pressure was
raised to 45.34 inches (1150 mm.), no explosion occurred; but when the
pressure was further raised to 59.34 inches (1505 mm., or very nearly two
atmospheres absolute) the acetylene exploded, or dissociated into its
elements.

Acetylene readily polymerises when heated, as has been stated in Chapter
II., where the meaning of the term "polymerisation" has been explained.
The effects of the products of the polymerisation of acetylene on the
flame produced when the gas is burnt at the ordinary acetylene burners
have been stated in Chapter VIII., where the reasons therefor have been
indicated. The chief primary product of the polymerisation of acetylene
by heat appears to be benzene. But there are also produced, in some cases
by secondary changes, ethylene, methane, naphthalene, styrolene,
anthracene, and homologues of several of these hydrocarbons, while carbon
and hydrogen are separated. The production of these bodies by the action
of heat on acetylene is attended by a reduction of the illuminative value
of the gas, while owing to the change in the proportion of air required
for combustion (_see_ Chapter VIII.), the burners devised for the
consumption of acetylene fail to consume properly the mixture of gases
formed by polymerisation from the acetylene. It is difficult to compare
the illuminative value of the several bodies, as they cannot all be
consumed economically without admixture, but the following table
indicates approximately the _maximum_ illuminative value obtainable
from them either by combustion alone or in admixture with some non-
illuminating or feebly-illuminating gas:

________________________________________________
| | | |
| | | Candles per |
| | | Cubic Foot |
|______________|___________________|_____________|
| | | |
| | | (say) |
| Acetylene | C_2H_2 | 50 |
| Hydrogen | H_2 | 0 |
| Methane | CH_4 | 1 |
| Ethane | C_2H_6 | 7 |
| Propane | C_3H_8 | 11 |
| Pentane | C_5H_12 (vapour) | 35 |
| Hexane | C_6H_14 " | 45 |
| Ethylene | C_2H_4 | 20 |
| Propylene | C_3H_6 | 25 |
| Benzene | C_6H_6 (vapour) | 200 |
| Toluene | C_7H_8 " | 250 |
| Naphthalene | C_10H_8 " | 400 |
|______________|___________________|_____________|

It appears from this table that, with the exception of the three
hydrocarbons last named, no substance likely to be formed by the action
of heat on acetylene has nearly so high an illuminative value--volume for
volume--as acetylene itself. The richly illuminating vapours of benzene
and naphthalene (and homologues) cannot practically add to the
illuminative value of acetylene, because of the difficulty of consuming
them without smoke, unless they are diluted with a large proportion of
feebly- or non-illuminating gas, such as methane or hydrogen. The
practical effect of carburetting acetylene with hydrocarbon vapours will
be shown in Chapter X. to be disastrous so far as the illuminating
efficiency of the gas is concerned. Hence it appears that no conceivable
products of the polymerisation of acetylene by heat can result in its
illuminative value being improved--even presupposing that the burners
could consume the polymers properly--while practically a considerable
deterioration of its value must ensue.

The heat of combustion of acetylene was found by J. Thomson to be 310.57
large calories per gramme-molecule, and by Berthelot to be 321.00
calories. The latest determination, however, made by Berthelot and
Matignon shows it to be 315.7 calories at constant pressure. Taking the
heat of formation of carbon dioxide from diamond carbon at constant
pressure as 94.3 calories (Berthelot and Matignon), which is equal to
97.3 calories from amorphous carbon, and the heat of formation of liquid
water as 69 calories; this value for the heat of combustion of acetylene
makes its heat of formation to be 94.3 x 2 + 69 - 315.7 = -58.1 large
calories per gramme-molecule (26 grammes) from diamond carbon, or -52.1
from amorphous carbon. It will be noticed that the heat of combustion of
acetylene is greater than the combined heats of combustion of its
constituents; which proves that heat has been absorbed in the union of
the hydrogen and carbon in the molecule, or that acetylene is
endothermic, as elsewhere explained. These calculations, and others given
in Chapter IX., will perhaps be rendered more intelligible by the
following table of thermochemical phenomena:

_______________________________________________________________
| | | | |
| Reaction. | Diamond | Amorphous | |
| | Carbon. | Carbon. | |
|________________________________|_________|___________|________|
| | | | |
| (1) C (solid) + O . . . | 26.1 | 29.1 | ... |
| (2) C (solid) + O_2 . . . | 94.3 | 97.3 | ... |
| (3) CO + O (2 - 1) . . . | ... | ... | 68.2 |
| (4) Conversion of solid carbon | | | |
| into gas (3 - 1) . . . | 42.1 | 39.1 | ... |
| (5) C (gas) + O (1 + 4) . . | ... | ... | 68.2 |
| (6) Conversion of amorphous | | | |
| carbon to diamond . . | ... | ... | 3.0 |
| (7) C_2 + H_2 . . . . | -58.1 | -52.1 | ... |
| (8) C_2H_2 + 2-1/2O_2 . . | ... | ... | 315.7 |
|________________________________|_________|___________|________|

W. G. Mixter has determined the heat of combustion of acetylene to be
312.9 calories at constant volume, and 313.8 at constant pressure. Using
Berthelot and Matignon's data given above for amorphous carbon, this
represents the heat of formation to be -50.2 (Mixter himself calculates
it as -51.4) calories. By causing compressed acetylene to dissociate
under the influence of an electric spark, Mixter measured its heat of
formation as -53.3 calories. His corresponding heats of combustion of
ethylene are 344.6 calories (constant volume) and 345.8 (constant
pressure); for its heat of formation he deduces a value -7.8, and
experimentally found one of about -10.6 (constant pressure).

THE ACETYLENE FLAME.--It has been stated in Chapter I. that acetylene
burnt in self-luminous burners gives a whiter light than that afforded by
any other artificial illuminant, because the proportion of the various
spectrum colours in the light most nearly resembles the corresponding
proportion found in the direct rays of the sun. Calling the amount of
monochromatic light belonging to each of the five main spectrum colours
present in the sun's rays unity in succession, and comparing the amount
with that present in the light obtained from electricity, coal-gas, and
acetylene, Muensterberg has given the following table for the composition
of the several lights mentioned:

______________________________________________________________________
| | | | | |
| | Electricity | Coal-Gas | Acetylene | |
| |________________|__________________|_______________|_______|
| Colour | | | | | | | |
| in | | | | | | With | |
| Spectrum.| Arc. | Incan- | Lumin- | Incan- | Alone.| 3 per | Sun- |
| | | descent.| ous. | descent.| | Cent. | light.|
| | | | | | | Air. | |
|__________|______|_________|________|_________|_______|_______|_______|
| | | | | | | | |
| Red | 2.09 | 1.48 | 4.07 | 0.37 | 1.83 | 1.03 | 1 |
| Yellow | 1.00 | 1.00 | 1.00 | 0.90 | 1.02 | 1.02 | 1 |
| Green | 0.99 | 0.62 | 0.47 | 4.30 | 0.76 | 0.71 | 1 |
| Blue | 0.87 | 0.91 | 1.27 | 0.74 | 1.94 | 1.46 | 1 |
| Violet | 1.08 | 0.17 | 0.15 | 0.83 | 1.07 | 1.07 | 1 |
| Ultra- | | | | | | | |
| Violet | 1.21 | ... | ... | ... | ... | ... | 1 |
|__________|______|_________|________|_________|_______|_______|_______|

These figures lack something in explicitness; but they indicate the
greater uniformity of the acetylene light in its proportion of rays of
different wave-lengths. It does not possess the high proportion of green
of the Welsbach flame, or the high proportion of red of the luminous gas-
flame. It is interesting to note the large amount of blue and violet
light in the acetylene flame, for these are the colours which are chiefly
concerned in photography; and it is to their prominence that acetylene
has been found to be so very actinic. It is also interesting to note that
an addition of air to acetylene tends to make the light even more like
that of the sun by reducing the proportion of red and blue rays to nearer
the normal figure.

H. Erdmann has made somewhat similar calculation, comparing the light of
acetylene with that of the Hefner (amyl acetate) lamp, and with coal-gas
consumed in an Argand and an incandescent burner. Consecutively taking
the radiation of the acetylene flame as unity for each of the spectrum
colours, his results are:

__________________________________________________________________
| | | | |
| | | | Coal-Gas |
| Colour in | Wave-Lengths, | |_______________________|
| Spectrum | uu | Hefner Light | | |
| | | | Argand | Incandescent |
|___________|_______________|______________|________|______________|
| | | | | |
| Red | 650 | 1.45 | 1.34 | 1.03 |
| Orange | 610 | 1.22 | 1.13 | 1.00 |
| Yellow | 590 | 1.00 | 1.00 | 1.00 |
| Green | 550 | 0.87 | 0.93 | 0.86 |
| Blue | 490 | 0.72 | 1.27 | 0.92 |
| Violet | 470 | 0.77 | 1.35 | 1.73 |
|___________|_______________|______________|________|______________|

B. Heise has investigated the light of different flames, including
acetylene, by a heterochromatic photometric method; but his results
varied greatly according to the pressure at which the acetylene was
supplied to the burner and the type of burner used. Petroleum affords
light closely resembling in colour the Argand coal-gas flame; and
electric glow-lamps, unless overrun and thereby quickly worn out, give
very similar light, though with a somewhat greater preponderance of
radiation in the red and yellow.

____________________________________________________________________
| | | |
| | Percent of Total | |
| Light. | Energy manifested | Observer. |
| | as Light. | |
|____________________________|___________________|___________________|
| | | |
| Candle, spermaceti . . | 2.1 | Thomsen |
| " paraffin . . . | 1.53 | Rogers |
| Moderator lamp . . . | 2.6 | Thomsen |
| Coal-gas . . . . . | 1.97 | Thomsen |
| " . . . . . | 2.40 | Langley |
| " batswing . . . | 1.28 | Rogers |
| " Argand . . . | 1.61 | Rogers |
| " incandesce . . | 2 to 7 | Stebbins |
| Electric glow-lamp . . | about 6 | Merritt |
| " " . . | 5.5 | Abney and Festing |
| Lime light (new) . . . | 14 | Orehore |
| " (old) . . . | 8.4 | Orehore |
| Electric arc . . . . | 10.4 | Tyndall; Nakano |
| " . . . . | 8 to 13 | Marks |
| Magnesium light . . . | 12.5 | Rogers |
| Acetylene . . . . | 10.5 | Stewart and Hoxie |
| " (No. 0 slit burner | 11.35 | Neuberg |
| " (No. 00000 . . | | |
| Bray fishtail) | 13.8 | Neuberg |
| " (No. 3 duplex) . | 14.7 | Neuberg |
| Geissler tube . . . | 32.0 | Staub |
|____________________________|___________________|___________________|

Violle and Fery, also Erdmann, have proposed the use of acetylene as a
standard of light. As a standard burner Fery employed a piece of
thermometer tube, cut off smoothly at the end and having a diameter of
0.5 millimetre, a variation in the diameter up to 10 per cent. being of
no consequence. When the height of the flame ranged from 10 to 25
millimetres the burner passed from 2.02 to 4.28 litres per hour, and the
illuminating power of the light remained sensibly proportional to the
height of the jet, with maximum variations from the calculated value of
+-0.008. It is clear that for such a purpose as this the acetylene must be
prepared from very pure carbide and at the lowest possible temperature in
the generator. Further investigations in this direction should be
welcome, because it is now fairly easy to obtain a carbide of standard
quality and to purify the gas until it is essentially pure acetylene from
a chemical point of view.

L. W. Hartmann has studied the flame of a mixture of acetylene with
hydrogen. He finds that the flame of the mixture is richer in light of
short wave-lengths than that of pure acetylene, but that the colour of
the light does not appear to vary with the proportion of hydrogen
present.

Numerous investigators have studied the optical or radiant efficiency of
artificial lights, _i.e._, the proportion of the total heat plus
light energy emitted by the flame which is produced in the form of
visible light. Some results are shown in the table on the previous page.

Figures showing the ratio of the visible light emitted by various
illuminants to the amount of energy expended in producing the light and
also the energy equivalent of each spherical Hefner unit evolved have
been published by H. Lux, whose results follow:

_______________________________________________________________________
| | | | | |
| | Ratio of | Ratio of | Mean | Energy |
| | Light | Light | Spherical | Equiva- |
| Light. | emitted to | emitted to | Illuminat- | lent to 1 |
| | Total | Energy | ing Power. | Spherical |
| | Radiation. | Impressed. | Hefners. | Hefner in |
| | | | | Watts. |
|____________________|____________|____________|____________|___________|
| | | | | |
| | Per Cent. | Per Cent. | | |
| Hefner lamp | 0.89 | 0.103 | 0.825 | 0.108 |
| Paraffin lamp, 14" | 1.23 | 0.25 | 12.0 | 0.105 |
| ACETYLENE, 7.2 | | | | |
| litre burner | 6.36 | 0.65 | 6.04 | 0.103 |
| Coal-gas incandes- | | | | |
| cent, upturned | 2.26-2.92 | 0.46 | 89.6 | 0.037 |
| " incandes- | | | | |
| cent, inverted | 2.03-2.97 | 0.51 | 82.3 | 0.035 |
| Carbon filament | | | | |
| glow-lamp | 3.2-2.7 | 2.07 | 24.5 | 0.085 |
| Nernst lamp | 5.7 | 4.21-3.85 | 91.9 | 0.073 |
| Tantalum lamp | 8.5 | 4.87 | 26.7 | 0.080 |
| Osram lamp | 9.1 | 5.36 | 27.4 | 0.075 |
| Direct-current arc | 8.1 | 5.60 | 524 | 0.047 |
| " " enclosed | 2.0 | 1.16 | 295 | 0.021 |
| Flame arc, yellow | 15.7 | 13.20 | 1145 | 0.041 |
| " " white | 7.6 | 6.66 | 760 | 0.031 |
| Alternating- | | | | |
| current arc | 3.7 | 1.90 | 89 | 0.038 |
| Uviol mercury | | | | |
| vapour lamp | 5.8 | 2.24 | 344 | 0.015 |
| Quartz lamp | 17.6 | 6.00 | 2960 | 0.014 |
|____________________|____________|____________|____________|___________|

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