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767
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sat
REESE LIBRARY
_ru_n — n—l/v
UNIVERSITY OF CALIFORNIA.
Deceived
Accession No.
Ju^lt*
J U . Clats No.
Pure and
Perfect
Combustion
Obtained the only
Medal awarded for
Light by the
Royal Cornwall
Polytechnic
Society, 1897.
»~ ACETYLENE GAS. ^«
All Householders in Town or Country can make their own Gas by
using the low pressure and only
SAFE GENERATOR YET INVENTED.
Commencing at
each for a Complete Installation.
Small Towns, Villages, Churches, Public Buildings, Private Residences,
Shooting Boxes, Concert Halls, Theatres, Schools, Hospitals, Factories,
Warehouses, Railway Stations, also Railway Carriages, Trams, 'Buses,
Yachts, Carriages, and Vehicles of every description, can be immediately
supplied with this Gas, producing the best known light of the present day.
Offices : S*. Olave's House, Ironmonger Lane, LONDON,
WHERE ALL COMMUNICATIONS SHOULD BE SENT.
Sole Makers of the "ACT" Burner, which NEVER CLOGS.
ADVERTISEMENTS. n.
The "YAHR"
Acetylene Cycle Lamp.
The only Cycle Lamp in which the turning off
stops Generation of Gas, and which can be
re-lighted immediately upon being turned on.
SIMPLEST,
SAFEST,
W CLEANEST,
And Least Troublesome of any Lamp
yet invented.
CANNOT EXPLODE.
Will Burn 7% hours. Weight about 16 ounces.
All Nickel Plated. Pits ordinary Lamp Bracket.
Wholesale from the Patentees and Makers :
REHB HOLUDHY & SONS, Ltd.
Acetylene Gas Engineers and Carbide Manufacturers,
HUDDERSFIELD, ENGLAND.
lit.
ADVERTISED!
The "FOWLER"
PATENT PORTABLE GENERATOR
FOR
OPTICAL LANTERNS, PHOTOGRAPHERS, etc.
Possesses
the following
Important
Advantages :—
Perfect in Principle
and Construction.
ABSOLUTELY SAFE
in use.
Automatic Action.
Steady Light.
No Smoke.
Possesses
the following
Important
A dvantages : —
Gas Thoroughly
Purified.
Quantity of Gas
generated
may be regulated,
or action
stopped at any
moment.
No Loose Fittings.
5? Requires no fixing.
Write for Catalogue and all particulars as to Sizes and Price.
CALCIUM CARBIDE supplied at market prices.
THE "FOWLER" ACETYLENE CAS CO.,
OFFICE AND WORKS—
298, Marsh Lane, Bootle, LIVERPOOL.
J. K. CLARKSON, T. R. FOWLER,
Manager & Secretary. Consulting Engineer.
ADVERTISEMENTS.
The "FOWLER"
PATENT GENERATOR.
For Country Houses/ Churches, Schools, Factories,
Railway Stations, etc., etc.
*-J&&&~>
Low Pressure,
Entirely
Automatic
Gas envolved
ONLY
as consumed.
ABSOLUTELY
SAFE
in the hands of
any inexperienced
person.
Attention
required, less than
Five minutes
daily.
fGiacs
The "Fowler" Generator has MANY most IMPORTANT advantages.
Write for full particulars to
The "FOWLER" Acetylene Gas Co.,
298, Marsh Lane, Bootle, Liverpool*
J. K. CLARKSON, Manager & Secretary. T. R. FOWLER, Consulting Engineer
ADVERTISEMENTS.
Artificial Sunlight ! ! Artificial Sunlig-ht ! !
BY ROYAL LETTERS PATENT.
The Light of the Future.
"THE SflFETY"
flcetyleije Gas Generator Co.,
HALIFAX.
Sole Patentees and Manufacturers of
"The Safety" Acetylene Gas Generators
for Lighting Churches, Factories, Houses, Hotels,
Railway Stations. Schools, Shooting Lodges. Shops, and Stables,
situated in the country, and other buildings.
The illuminating power of Acetylene Gas is fifteen times
that of coal gas. Does not pollute the atmosphere like coal gas.
Has a very pungent smell, enabling the slightest leakage to be
at once detected.
The Safest, Simplest, Cheapest, and
Most Perfect Apparatus on the market.
Each Machine Tested before leaving the Works.
Working Instructions sent with each Machine.
Any person can do all that is necessary without risk.
Nothing to get out of order. Gas generated automatically.
Less attention required than demanded by an ordinary paraffin lamp.
CERTIFIED BY A COMPETENT AUTHORITY.
Prices and further particulars on application.
ADVERTISEMENTS.
The THORNTON-SCARTH
PATENT ACETYLENE GENERATOR
Of HIGHEST POSSIBLE QUALITY, STRENGTH & FINISH.
Constructed on sound engineering principles, and each machine thoroughly
tested before delivery.
Registered Trade Mark—THORSCAR.
Highest Awards
at
BERLIN
(1st International
Acetylene Exhibition)
MANCHESTER,
DUDLEY,
EVESHAM,
etc.
No Levers, Chains, Ball-Cocks or anything else to get out of order.
No Governors required, the low pressure being constant and self-regulating.
No Safety-Valves necessary as the machine never makes too much gas.
The Gas delivered Cool, Dry and PURIFIED.
Sole Makers (Patented all over the World)-
The Thornton-Scarlh Automatic Lighting Syndicate, Ltd,
Vittoria Street, BIRMINGHAM.
Also Makers of Special Lines in Burners and Fittings to the Trade.
The Birmingham Carbide Co., Ltd.!
/Ifcanufacturers ot JSeet (Slualttg Garbtfce of Calcium,
Offlces-37, Vittoria St. BIRMINGHAM. Works Artillery St.
Telegrams—" Carbide, Birmingham, "
ADVERTISEMENTS.
READ HOLLIDAY A SONS, Ltd.
PATENT
AUTOMATIC ACETYLENE GAS GENERATOR
Hundreds of
these Machines
in use !
Portable
Machines for
Contractors,
Dock-yards,
Canals, &c.
Simplest and
Best.
These Machines
will
AUTOMATICALLY
Feed Existing
Gasometers
of any size.
Machines arc made all sixes to suit customers, and the methods of working arc very simple,
There is nothing to grt out of order: and any person, maidservant,' gardener, or
groom can re-Charge it iind do all that is necessary without risk. A t'c\v words as direc-
tions are attached to every machine. This apparatus is constructed to generate the gas
automatically as used. 'and when charged requires no further attention. The
generators can he discharged of residual matter (lime) and RKVl LLKI) in a FEW MINUTKS,
and in less time than an ordinary paraffin lamp can be trimmed and refilled. There is no
danger of any excessive pressure in machines. Every Machine is tested before Icaviii},'
the workshops to insure all beinjr perfect. These Machines comply with Insurance-
tipOS. Special Apparatus made for Li,<?htin<r Villages, &c. An 'Appa
Lights requires Only the attendance of a man for an hour a day.
Apparatus for over 1,000
ACETYLENE GAS BURNERS. No Deposit. Most Illumination. Small Cost.
For Partlclats apply to Patentees and Makers:
READ HOLLIDAY & SONS, Ld.,
Acetylene Gas Engineers and Carbide Manufacturers,
HUDDERSFIELD, England.
ACETYLENE GAS
AND
CALCIUM CARBIDE.
ACETYLENE GAS,
ITS
NATURE, PROPERTIES
AND USES ; ALSO
CALCIUM CARBIDE,
ITS
COMPOSITION, PROPERTIES
AND
METHOD OF MANUFACTURE.
BY
G. F. THOMPSON,
CONSULTING ENGINEER.
LIVERPOOL.
PUBLISHED BY THE AUTHOR,
LOMBARD CHAMBERS, BIXTETH STREET,
1898.
[ALL RIGHTS RESERVED].
CALIFOK^L
— i —•«=«-
PREFACE.
The present work originated in a lecture delivered by
the Author before the Liverpool Polytechnic Society, the
primary object of which being to make known the properties
of Acetylene, and by pointing out its many and distinct
advantages in contradistinction to its supposed dangerous
character, remove the suspicion attaching to it, and allay the
unfounded and somewhat undefined fears which have been
aroused by the occurrence of a few accidents through its
agency.
Acetylene, owing to its high value as an illuminant
and other valuable properties, is intensely interesting from
both scientific and commercial standpoints, but owing to the
fact that its real properties are but little known, and that a
few accidents have occurred in consequence thereof, reports
have been freely circulated as to its being a highly dangerous
compound, the result being that it is regarded by the general
public with a considerable amount of suspicion.
It was with a view to dissipating the erroneous impres-
sions prevalent that the Author was prompted to bring the
subject before his Society, and by giving some particulars of
the nature and properties of Acetylene and its base, Calcium
Carbide, extend the knowledge of this simple yet valuable gas.
That a large number are interested in the subject was
proved by the receipt of numerous enquiries respecting
Acetylene and applications for copies of the lecture. The
receipt of these communications impressed the Author with
the evident necessity for an authoritive work on the subject,
ACETYLENE.
and he has therefore been prompted to prepare such a \vorkr
which he now submits and dedicates to all those who may in
any way be interested in artificial lighting generally, or in
Acetylene in particular, as an illuminant or as applied to other
purposes.
Coal gas as an illuminant having now been in use
nearly a century, it would appear reasonable to suppose
that public knowledge of the subject would be fairly accurate
and general, yet there are few things in common use involving
scientific principles or chemical reactions in regard to which
more ignorance or erroneous ideas are displayed. That such
is unfortunately the case is proved by the fact that fatalities
through its agency are of frequent occurrence, cases of poison-
ing and explosion being common, the latter occurring occasion-
ally even at Gas Works, where it might be expected a good
knowledge of the nature of Gas prevailed and the greatest care
would be exercised in connection therewith.
These accidents are reported by the press almost as
every-day and common-place events, are read by the general
public, commented upon and soon forgotten, but when an
accident occurs in connection with any new innovation, be it
trifling or serious, sensational accounts of same are immediately
published, greatly to the detriment of the innovation, however
valuable or important it may be, and the pessimistic tendency
of the average mind usually prompts a condemnation of the whole
thing without any consideration as to its possible advantages.
Acetylene regarded as an innovation has suffered from
this cause, but in that respect it is not alone: all innovations of
a scientific origin have in more or less degree suffered in like
manner.
PREFACE.
Coal gas during the early days of its introduction was-
regarded with considerable distrust owing to a few mishaps
which occurred, but which were almost invariably traceable to
ignorance or carelessness, or both.
The adoption of the electric light was also much
retarded in its early stages by similar causes, unfounded fears
being aroused regarding the danger and subtlety of electricity.
Acetylene being the latest scientific production and a
terra incognita to the majority, public apprehension is aroused
by the slightest mishap, and accounts of accidents have been
distorted and exaggerated, but the introduction of a compound
of this description, with comparatively unknown properties,
must for a time be impeded by accident through improper
usage.
Acetylene as an illuminant compared with ordinary
coal gas involves much less risk in its use, its distinct and
pungent odour making its presence known long before any
dangerous quantity might be present, and in comparison with
water gas the risk is still less owing to the fact that the
latter is practically inodorous and its presence is not detected
until symptoms of poisoning are developed.
These facts, therefore, shew that a great deal of un-
founded and unnecessary fear has been aroused in regard to
Acetylene which is not only unjust to it, but absurd in view
of the general enlightenment of the present age.
The Author was early convinced of the importance of
the discovery by which the synthetic production of Acetylene
became a commercial possibility, and he has taken an active
interest in the subject from the time when Calcium Carbide
first became a commercial article.
ACETYLENE.
The present work has been prepared with a view to its
being a complete resume of the subject and is in every
respect a record of the state of knowledge at the present time
in regard to Acetylene, and no pains have been spared to
render it worthy of being accepted as a standard work on the
subject.
The design of the work is to expound the general
principles governing the subject and the various conditions
involved ; no description of specific apparatus is therefore
attempted, owing to the variety of forms adopted by the
several manufacturers, each one possessing features and ad-
vantages peculiar to itself.
The Author, while not assuming to be an authority in
regard to the chemical aspect of the subject, yet claims to have
acquired some knowledge of the nature and properties of
Acetylene, and to have ascertained the best conditions under
which it may be generated and utilized.
The Author desires to acknowledge the courtesy of
Professor Vivian B. Lewes in permitting him to quote the
results of some of his experiments in regard to the properties
of Acetylene. He also wishes to acknowledge information
derived from articles in " The Journal of Gas Lighting"
"The Engineer" "Engineering" and other periodicals, and
communications to learned societies by Professor Lewes, M.
Moissan, Dr. Pictet, M. Ravel, Dr. Bunte, and other eminent
scientific authorities who have given special attention to the
subject.
G. F. T.
LIVERPOOL, April, 1898.
CONTENTS.
INTRODUCTION.
The Standard of Excellence in Artificial Illumination —
Advent of Electricity — New Conditions and Possibilities — Incan-
descent Gas — Acetylene Compared with other Illuminants — Cal-
cium Carbide — Action of Electric Furnace — Synthetic Formation
of Acetylene — Simplicity of Process — Portability — Photometric
Value of Flame — Spectrum Analysis — Actinic Quality and other
Properties of Light — Its Strong Odour an Advantage — Innoxious
Nature of Flame — Imaginary Dangers — Real Dangers. Page 13
CHAPTER I.
HISTOllICAL. SOURCES OF ACETYLENE.
Acetylene not a Recently Discovered Gas — First Discovery
and Isolation — Investigations by Berthelot, Wohler and Others-
Named "Acetylene" by Berthelot — First Production of Calcic
Carbide by Wohler — Various Methods of Production as Laboratory
Experiments — Carbides of the Dyad Metals — Methods of Prepara-
tion— Willson's Discovery of Electro-thermic Method of Producing
Calcic Carbide. Page 21
CHAPTER II.
ACETYLENE, NATURE AND PROPERTIES GENERALLY.
Composition of the Gas— Specific Gravity — Comparative
Density — Photometric Value as Compared with Coal Gas— Tem-
perature of Combustion — Ratio of Consumption of Oxygen —
Calorific Value as Compared with other Gases — Less Poisonous
than Coal Gas — Nature and Amount of Impurities Present —
Range of Explosibility — Less Dangerous than Coal Gas — Value as
an Eiiricher of other Gases. Page 27
10 ACETYLENE.
CHAPTER III.
ACETYLENE AS AN ILLUMINANT.
Ideal Conditions in Artificial Illumination — Various Systems
Compared — Illuminating Power of Hydrocarbons Generally —
Advantages of Acetylene — Conditions Necessary to Development
of highest degree of Luminosity — Types and Sizes of Burners —
Rates of Consumption — Penetrative Power of Acetylene Light as
Compared with other Illuminants — Suitability for all Photographic
and Optical Purposes — Application to Cycle and Carriage Lamps
— Domestic Lighting — Municipal and Industrial Lighting —
Application to Lighthouses, Ships and Buoys — Relative Cost —
Method of Computing Photometric Values of Illuminants —
Bunsen Photometer. Page 34
CHAPTER IV.
COMMERCIAL PRODUCTION OP CALCIUM CARBIDE.
Process of Manufacture — Materials Employed, Proportion
and Preparation of Same — The Electric Furnace — Simplicity and
Advantages of Process — Method of Manufacture insures Purity
— Rate of Production — Standard of Quality — The Works at Foyers
—The Plant at Niagara Falls— Other Works. Page 47
CHAPTER V.
CALCIUM CARBIDE, COMPOSITION AND PROPERTIES.
Carbide an Endo-thermic Compound — Not an Explosive —
Highly Hygroscopic Nature — Method of Decomposition and
resulting Chemical Reactions — Conditions affecting the Gas
Evolved — Carbide to give off Smokeless Gas — Methods of Ren-
dering Carbide less Hygroscopic. Page 54
CHAPTER VI.
GENERATING.
Physical Conditions Involved — Chemical Reactions —
Systems of Generating and Nature of Apparatus — "Automatic" or
"Dry" Process — Non-Automatic or "Wet" Process — "Combina-
tion" or "Retarded Reaction" Process — Conditions Involved in
each Method — Theoretical and Actual Yield of Gas — Risk of
Polymerization — Best Conditions of Generating — Points to be
observed in Design of Apparatus. Page 5D
CONTENTS. 11
CHAPTER VII.
PURIFYING AND DRYING.
Acetylene always More or Less Impure— Dangers of Impure
Gas — Ordinary Methods of Purifying Gases — Simple and Efficient
Methods — The Pictet Process — Cooling, Purification and Dehydra-
tion Necessary before Storage or Combustion — Condition of the
Gas Essential to Development of Highest Illuminating Power.
Page 61)
CHAPTER VIII.
STORAGE OF ACETYLENE.
In Gaseous Condition — By Absorption in Neutral Fluid —
By Compression — By Liquifaction — Relative Volume and Space
Occupied — Advantages and Disadvantages of the Several Methods
of Storage — Properties of the Gas under the Various Conditions.
Page 71
CHAPTER IX.
ACETYLENE AS A MOTIVE POWER.
Thero-dynamic Value Compared with Other Gases — Pro-
portions of Gas and Air at which Maximum Explosive Effect is
Developed — Consumption per H.P. per hour — Calorific Value as Fuel
Compared with other Materials — Relative Weight and Bulk. Page 79
CHAPTER X.
OTHER USES. APPLICATION OF ACETYLENE TO ARTS AND
INDUSTRIES.
The Formation of Organic Compounds from Inorganic
Materials — The Various Hydrocarbon Compounds — Manufacture
of Naphthaline, Benzol, Aniline Dyes — Alcohol — Cost of Acetylene
Light Compared with other Illuminants — Home Office and Local
Regulations relative to Calcium Carbide and Acetylene — Insurance
Restrictions — Conclusion. Page 83
PRINTED BY
GEO. MCALLISTER & Co.,
LIVERPOOL.
INTRODUCTION,
The many and important scientific discoveries of recent
years and the practical applications thereof have wrought
marked changes and much improvement in many conditions of
commercial, industrial, and social life, and the beneficial effects
thereof are seen in the activity of invention, the development
of higher ideals and the advancement of the standard of
excellence generally.
Although great improvement is evident in almost all
conditions of life, yet, in no department has progress been
more marked or rapid than in the matter of artificial
illumination.
During a period which is almost within the memory of
man, the standard of excellence in artificial lighting has been
raised from the feeble and flickering rush light to the brilliancy
of electricity and incandescent gas.
Before the advent of coal gas, the oil lamp and wax
candle were regarded as excellent illuminants, but the adoption
of gas at once raised the standard of both degree and quality
of light, and for a long period it was considered the acme of
perfection in artificial illumination.
The introduction of electricity for lighting purposes
tended to raise the standard still higher, and at the same time,
to materially alter the conditions of artificial illumination by
the introduction of the new elements of perfect safety and
14 ACETYLENE.
application under circumstances prohibitive to gas, which,
together with its greater convenience and adaptability have
made the possible uses, applications and effects of artificial
light practically unlimited, popular taste has been educated
and a demand created accordingly.
The incandescent gas system has to a large extent
supplied the demand for a higher degree and better quality in
light, and at the same time has proved the salvation of coal
gas as an illuminant. But while the Welsbach mantle has
increased the luminosity of coal gas, it has not tended to make
it any more portable nor applicable in remote or isolated
situations.
It is under the latter circumstances and in comparison
with ordinary gas and electricity that the attributes of Acety-
lene become most conspicuous, and mark it as the ideal
illuminant under certain conditions, possessing as it does
advantages attributable to no other source of artificial light.
The demand for a light of high illuminating value
other than electricity or incandescent gas and free from the
drawbacks of such, and the objections to, and dangers of oil
lamps, is therefore entirely met by the Acetylene flame, which
affords at once an illumination of high degree and perfect
quality, and while supplying an existing want has found
for itself special fields of usefulness in its peculiar suit-
ability for, and ease of adaptation to all photographic and
optical purposes in which perfect actinic quality and absolute
steadiness are the chief desiderata.
Amongst the more important scientific events of this
latter part of the Nineteeth Century, the discovery that in
the intense heat of the electric arc, bodies unaffected by the
INTRODUCTION. 15
highest calorific temperature may be easily fused, must be
accorded a prominent position.
This property of the electric arc has made possible a
much more extended research in the field of thermo-chemistry,
and at the same time has enabled the production of compounds
impossible to obtain by other means.
One of the most important of the new compounds pro-
ducible through the agency of the electric furnace is Calcium
Carbide, a substance formed by the fusion together of calcium
and carbon.
This substance possesses the property of combining
with and decomposing water, and is on the other hand decom-
posed by the water, one result of which chemical reaction
being the formation of a rich hydro- carbon gas, " Acetylene."
The evolution of gas under these conditions is a true
case of synthetic formation, the gas being produced by the direct
combination of its elements, carbon and hydrogen. The
process, therefore, by which the formation of Acetylene is
effected is the converse of that by which ordinary illuminating
gases are produced, and the synthetic as differing from the
analytic or distillation method insures one distinct advantage,
viz., that the product so built up is practically free from those
deleterious elements and compounds from which gas produced
by destructive distillation of carbonaceous materials is seldom
or never free.
The discovery of a means whereby the synthetic pro-
duction of Acetylene on a large scale from common and
comparatively inexpensive materials is now a practical
possibility, is one of the most important results of scientific
research, inasmuch as it has not only enabled the economical
16 ACETYLENE.
production of a valuable hydro-carbon compound, but has at
the same time thrown much light upon one of the most
wonderful of natural phenomena, viz., that mysterious working
of Nature by which apparently inexhaustible stores of liquid
and gaseous hydro-carbons have been and are still being
formed.
Although the evolution of Acetylene from calcium
carbide as a laboratory experiment has been known to
chemistry for a considerable length of time — the carbide being
prepared by a somewhat elaborate process — yet the direct
combination of calcium and carbon in the formation of the
carbide was thought to be impossible until accidentally revealed
by the action of the electric furnace.
The process by which Acetylene is evolved from the
carbide being of a very simple nature, the apparatus necessary
for its generation need not be either elaborate or expensive,
and the acquisition of a practical knowledge of the modus
operandi is within the scope of the most ordinary intellect.
The photometric value or illuminating power of the
Acetylene flame is more than 15 times that of coal gas, being
about 50 candle power when consumed at the rate of one cubic
foot per hour ; the flame also possesses other qualities besides
that of intense brilliancy, viz., purity, steadiness and freedom
from noxious bye-products, and is at the same time a compara-
tively cool flame.
The quality of the Acetylene light is almost equal to
that of sunlight, being practically pure white, which is proved
by the close resemblance of its spectrum to the solar spectrum.
This attribute therefore makes the Acetylene light, in this
respect, superior to all other artificial illuminants, as owing to
its actinic property all colours appear the same as by daylight.
This quality renders the light particularly suitable for
photographic purposes.
Under proper conditions as to density and pressure the
flame is perfectly steady and free from the flickering peculiar
to coal gas. In this respect, the light is equal to incandescent
gas and electricity.
Acetylene possesses a peculiar and unmistakeable odour
of such a pungent and penetrating character as to render the
atmosphere practically unbearable long before the percentage
of gas present would be sufficient to cause risk of explosion.
This property is of much advantage as constituting a safe-
guard in its use, the slightest leakage being readily detected.
Acetylene is of much greater density, and consequently
of a higher specific gravity than other hydro-carbon gases;
consequently it will not flow through a given sized aperture
as readily or as quickly as coal gas ; and when it is considered
that the largest sized Acetylene burners pass only about one
cubic foot per hour, it follows that if the gas were escaping at
this rate, there would be in a given time an accumulation of
only one-fifth the quantity of coal gas which would escape
through an ordinary burner during an equal period.
That Acetylene is much less poisonous than coal gas is
proved by the fact that it is a nearly pure gas, and practically
free from sulphuretted and phosphoretted hydrogen with which
coal gas is always more or less contaminated, and which con-
stitute the really poisonous elements of such gas.
In comparison with other hydro-carbon flames that of
Acetylene is a comparatively cool one, developing a tempera-
ture of only about two- thirds that of the flame of coal gas, and
18 ACETYLENE.
when it is considered that for a given degree of illumination
only one-fifteenth the quantity of Acetylene is required, and
that the flame is of a much lower temperature, it is evident
that the atmosphere of a room would not become heated to
anything approaching the same degree as if the light were
derived from coal gas.
From the foregoing it will be obvious that the so-called
" dangers " of and other objections to Acetylene raised by
prejudiced persons ignorant of its properties are purely
imaginary, and that on the other hand the many advantages
peculiar to the Acetylene flame as a source of artificial light,
the simplicity of the process of production, its portability
and applicability under circumstances where an equal illu-
mination by other means would be almost impossible, tend
to prove this gas to be an ideal illuminant, possessing as it
does properties which make its light in many respects superior
to that obtained by other artificial means.
The extreme simplicity of the process by which Acety-
lene may be generated, while being one of its chief advantages,
has at the same time proved a disadvantage owing to its very
simplicity having attracted enthusiastic but unskilled amateurs,
and others who have entered the field of experiment with a
very imperfect knowledge of the nature or properties of
Carbide or of Acetylene, the result being that in a few cases
accidents have occurred through its agency attended with
more or less disastrous consequences. It is therefore the blind
unintelligent experiments of ignorant persons which con-
stitute the real dangers of Acetylene, and it has consequently
suffered by the want of knowledge or carelessness of its
votaries, the disastrous results of whose ill-advised enthusiasm
INTRODUCTION. 19
Lave had the effect of bringing into disrepute one of the most
valuable articles which chemical research has evolved and
electrical science made a commercial possibility.
In all operations in which known physical conditions
are involved or known substances employed, the possible
or probable results, instead of being speculative or purely
conjectural, may, by having due regard to natural physical
forces and properties of matter and careful consideration of
the factors in the case, be pre-determined — theoretically — with
more or less degree of accuracy before being practically tested
by trial or so-called " experiment."
In view of the fact that literature bearing upon* all
branches or departments of physical science is available, ex-
periments of a purely speculative character in the fields of
Chemistry or Mechanism are inexcusable. But if entered
upon in ignorance of or indifference to underlying principles,
or conditions involved, and with indefinite views as to the
effects sought or thought possible of attainment, the most
probable results will be waste of time and material, disappoint-
ment, and perhaps even disaster.
" A little knowledge is a dangerous thing," and usually
tends to beget one or other of two conditions of mind, namely,
a childish and undefined fear on the one hand, or a reckless
temerity and indifference as to consequences on the other.
This reasoning emphasizes the fallacy of entering upon
physical operations with insufficient or imperfect acquaintance
with the properties of matter or laws of nature, and without
clearly formed ideas as to the effects sought or possible of
attainment.
20 ACETYLENE.
Should this, work, therefore, by an exposition of the
nature and properties of Acetylene and of Calcium Carbide add
to the scientific knowledge of the subject, and so prove of
assistance to those interested and enable them to avoid specu-
lative or risky experiments, and the probable disappointing or
disastrous consequences thereof, the labour expended upon its
compilation will not have been in vain.
CHAPTER L
HISTORY OF ACETYLENE.
Acetylene is not, as many appear to. suppose, a recently
discovered gas, but on the contrary has been known to experi-
mental chemistry for a considerable length of time — something
over sixty years.
Its discovery or original production and recognition as
differing from other gaseous compounds was one result of the
researches and experiments made by the eminent chemist,
Edmund Davy, to ascertain and determine the properties of
the Monad and Dyad metals.
During his investigation of the metal Potassium and
while endeavouring to obtain it from its carbonate, he pro-
duced a compound of potassium and carbon, which was decom-
posable by water, the reaction causing the evolution of a highly
inflammable gas, which he is said to have named "Klumene."
About the year 1859 the eminent French chemist
Berthelot, while conducting researches in the field of the
Hydro-carbon compounds, discovered the fact that a stream of
hydrogen passed through an electric arc playing between
carbon electrodes was converted into a rich hydro-carbon gas,
and which on analysis he found to bear a chemical relationship
to the organic radical Acetyl, and he therefore named the
compound " Acetylene."
22 ACETYLENE.
At about this same period the celebrated German
chemist Wohler found that a mixture composed of an alloy of
zinc and calcium and carbon when fused together at a high
temperature was converted into a substance which, on being
decomposed with water, gave off Acetylene Gas, and to Wohler,
therefore, is due the credit of having first produced Calcium
Carbide, and of having discovered a means whereby Acetylene
could be produced synthetically upon a comparatively large
scale from simple and inexpensive materials.
Berthelot's and Wohler's investigations and experiments,
while revealing the true nature and valuable properties of
Acetylene, were of great scientific importance as throwing
considerable light upon some of the mysteries of Natural
Phenomena, and as explaining those wonderful workings of
Nature by which almost inexhaustible quantities of both
liquid and gaseous hydro-carbons have been formed and are
now being drawn from the Storehouse in the form of
Petroleum and Natural Gas.
To produce Acetylene by Berthelot's method, a stream
of hydrogen is caused to pass through an electric arc playing
between carbon electrodes, the gas thereby becoming heated to
a high degree, some of it combines with the particles of free
carbon in the electric arc, forming Acetylene, which is carried
forward by the stream of hydrogen. To obtain the Acetylene
the mixed gases are passed through a solution of cuprous
chloride when the Acetylene separates in the form of a red
solid copper compound, this substance upon being decom-
posed by hydrochloric acid yields pure Acetylene.
The gas may also be produced by the decomposition
with water of Carbides of the Monad and Dyad metals other
HISTORY. 23
than Calcium, and Carbides of several of these metals have
been obtained by various experimenters.
Maquenne, in the early part of the present decade,
succeeded in producing Barium Carbide (BaC2) by heating-
together in an iron bottle a mixture of barium carbonate, car-
bon (charcoal), and powdered magnesium in the proportion of
barium carbonate 64'64, carbon 9*75, magnesium 25'61 per
cent. lie found, upon subjecting the mixture to a high tem-
perature for four minutes, the following reaction took place :
BaC03 + 3Mg + C = BaC2 + 3MgO.
The carbide produced was amorphous and yielded, on de-
composition with water, Acetylene mixed with free hydrogen.
Soon after this event Travers produced Calcium Car-
bide by fusing together a mixture of chloride of calcium,
metallic sodium and carbon, which, on decomposition with
water, gave off Acetylene in large quantities.
Although these experiments and discoveries were very •
interesting and of great scientific value, the "production of
Acetylene on a commercial scale from these compounds was
practically precluded owing to the costly nature of the
elements.
The production of Acetylene might still have been
regarded as merely a pretty laboratory experiment had not a
most fortunate circumstance revealed the fact that the desired
reaction could be brought about by means of the electric
furnace, and that Calcium Carbide could thereby be ' manu-
factured on a commercial scale from simple and inexpensive
materials. This discovery may therefore be justly regarded
as one of the more important scientific events of the latter part
of the nineteenth century.
24 ACETYLENE.
It has been found that in the high temperature of the
electric furnace carbides of calcium and other metals of that
group can be produced in a simple and economical manner by
the fusion of the oxides or carbonates of those metals with
carbon, and by the decomposition of such compounds with
water, the synthetic production of practically pure hydro-
carbon or Acetylene Gas is now a commercial possibility.
Prior to this discovery the only known and recognized
manner in which hydro-carbon illuminating gas could be
produced upon a commercial scale was by the destructive
distillation of solid or liquid carbonaceous materials and the
after separation from the resulting gas of a number of other
elements or compounds termed "bye-products."
The fact that calcic carbide could be produced by the
fusion together of oxide of calcium and carbon in the electric
furnace was discovered independently by Willson in America
and Moissan in France, and the credit of first discovery is
claimed by each country. But although in the former case,
it was one result of practical trial on a large scale, and in the
latter of scientific laboratory research, it was, in each instance,
accidental ; neither one of the experimenters being at the time
cognisant of the other's work, the credit is therefore equal.
There now, however, appears to be little doubt but that
•crystalline carbide of calcium was first produced by means of
the electric furnace, by Thomas Leopold Willson in America,
and that he had made a large quantity of the material prior to
Moissan's announcement of his observations as to its formation
under similar conditions.
The story of Willson's discovery is most interesting, as
HISTORY. 25
shewing how sometimes important innovations take their origin
in apparently insignificant incidents.
During the year 1889, Mr. T. L. Willson, an electrical
engineer, then of Leaksville, in North Carolina, while experi-
menting with an electric furnace with a view to obtaining the
metal Calcium by the reduction of its oxide in the electric arc,
fused together a mixture of powdered lime and anthracite, but
upon opening the furnace, instead of finding, as he anticipated,
a quantity of white shining metal, he found instead a dark-
coloured, heavy, crystalline substance resembling scoria or larva
from a volcano.
The material upon examination being found not to be
the substance sought — its true character not being recognized —
it was regarded as useless and was thrown into some water near
by. Immediately the water began to effervesce, and so violent
was the ebullition and so strong the odour of the gas bubbling
out, that it attracted attention and some more of the material was
made, which upon being more carefully examined than was
the first lot, was found to be carbide of calcium ; it was put
into water and the gas as it bubbled out was caught. The gas
proved to be pure Acetylene, and thus was discovered the
possibility of producing Acetylene synthetically upon a com-
mercial scale, and such the origin of a discovery likely to have
an important bearing upon industrial progress in the near
future, opening up as it does commercial possibilities scarcely
conceived by the most speculative imagination.
This phase of the subject is treated in Chapters IX. and
X., in which the possible uses and applications of Acetylene,
other than as an illuminant, are fully considered.
Carbides of Manganese, Sodium, Thorium and Yttrium
26 ACETYLEXE.
have been produced through the agency of the electric furnace,
all of which, on decomposition with water, give off Acetylene,
mixed in more or less quantity with ethylene, methane and
free hydrogen, also small quantities of liquid hydro-carbons.
Carbides of other metals of the Dyad and Earth-metal
groups may be produced by fusion of the elements in the
electric arc and will, on decomposition with water, also yield
Acetylene, but their use is practically precluded owing to
rarity or cost of production.
Calcium being the most abundant of the earth-metals
and consequently the least costly, and at the same time
usually found in a fairly pure state, as Lime or Chalk, it
becomes at once the most suitable for the production of carbide
on a commercial scale.
CHAPTER II.
ACETYLENE: ITS NATURE AND PROPERTIES
GENERALLY.
Acetylene, or as it is scientifically named " Ethine," is
a simple hydro-carbon compound consisting of twenty-four
parts by weight of carbon, and two parts by weight of
hydrogen, its chemical symbol being C2II2, meaning that it is
a compound of two atoms of carbon combined with two atoms
of hydrogen ; it is a clear colourless gas of a sp. gr. of 0'92.
It is, owing to its synthetic formation, the most pure,
and at the same time, the richest hydro -carbon gas containing
no less than 92'5 per cent, of carbon, hence the high illuminat-
ing power of its flame which far exceeds that of any other
known gas.
When perfectly pure and free from water vapour it
has an illuminating value of 50 candle-power per cubic footr
coal gas under similar conditions as to pressure having only an
average of 1 6 candle-power per Jive cubic feet ; the Acetylene
light is therefore more than 15 times the photometric value of
that of carburetted hydrogen or coal gas.
The light emitted by the Acetylene flame is practically
pure white and more nearly the quality of sunlight than that
of any other known illuminant.
ACETYLENE.
Its spectrum more closely resembles the solar spectrum
than that of any other artificial light, so that delicate
shades of colour appear the same as by daylight. This
constitutes one of the most valuable properties of Acetylene as
an illuminant.
It has a most unmistakeable and penetrating odour
somewhat resembling garlic, and when present in the propor-
tion of only one part in 10,000 parts of air is distinctly
perceptible, and long before there might be sufficient gas
present to cause explosion or asphyxiation, the inhalation
would produce headache in persons breathing it ; it also affects
the eyes, producing a smarting sensation. This property is
much in its favour as a safeguard in its use, the slightest
leakage being at once detected.
One burner passing one cubic foot per hour is sufficient
to brilliantly illuminate an apartment of 2,500 cubic feet area,
and if the gas were escaping at that rate for a period of nine or
ten hours there would not, at the end of that time, be sufficient
gas present to make an explosive mixture with that quantity
of air ; therefore, the danger of explosion through leakage or
through taps being inadvertently left open, is in the case of
Acetylene as compared with coal gas very much less, for the
reason that the largest Acetylene burners pass only a little
more than one cubic foot per hour, whilst on the other hand,
an ordinary gas burner passes five cubic feet per hour for only
about one-third the light value of the Acetylene, and further,
the specific gravity of Acetylene being 0'92 as against 0*43 for
coal gas, it follows that a very much less quantity of Acetylene
would flow through a given sized aperture in a given time
than would be the case with coal gas. It is therefore obvious
NATURE AND PROPERTIES GENERALLY. 29
that the prevailing popular belief as to Acetylene being more
dangerous than coal gas is fallacious.
The quantity of oxygen required for its complete com-
bustion is relatively low, being at the rate of two and a-half
volumes to one of Acetylene, so that when burned at the rate
of one cubic foot per hour the consumption of oxygen is only
two and a-half cubic feet per hour, producing about two cubic
feet of carbon dioxide (C02).
For an equal degree of illumination with coal gas, the
consumption of oxygen would be about nineteen cubic feet,
and the quantity of carbon dioxide given off about 8*25 cubic
feet besides certain quantities of sulphur dioxide, and
sulphuretted and phosphoretted hydrogen ; whereas, in the
case of Acetylene, the quantity of carbon dioxide is less than
one-fourth that quantity, and when the gas is purified, practi-
cally no sulphuretted or phosphoretted hydrogen or other
deleterious products of combustion.
Acetylene and oxygen ignite at a temperature of about
480° C, and the temperature of the flame is about 1,000° C.
The maximum degree of heat is developed when
Acetylene is burned with an equal volume of oxygen, the
temperature of combustion then being about 3,800° C.
M. Ravel places the temperature as high as 4,000° C.
Coal gas, on the other hand, requires a temperature of
600° C to ignite it, but developes on combustion in the
ordinary manner a temperature of 1,350° to 1,400° C, so that
the Acetylene flame, in comparison with that of coal gas, is a
distinctly cool one.
Acetylene, although a practically pure gas, usually
contains some impurities in greater or less rn^portjo.^ those
JE UB/fe^,
O* THB " KV
UNIVERSITY '
" ~- J
30 ACETYLENE.
commonly present being sulphuretted and phosphoretted
hydrogen, due to the presence of sulphate of calcium — gypsum
— and calcium phosphide in the lime, and to sulphur and phos-
phorous in the coke employed in the manufacture of the
carbide. Although these elements are to a large extent driven
off in the fusion of the calcium and carbon, still, if present in
large proportion certain quantities remain in the carbide.
Acetylene is also generally contaminated with ammonia
in more or less quantity formed by the combination of nitrogen
-derived from the coke with the hydrogen of the water during
the process of decomposition of the carbide, and which, when
present with oxygen in the form of an aqueous vapour acts
upon copper, silver, or mercury, forming acetylides of those
metals which are explosive, and will detonate if heated to a
sufficient degree, or are subjected to percussive action.
That Acetylene is a poisonous gas is now proved to be
untrue ; when pure it is relatively harmless and much less
poisonous than coal gas owing to the almost entire absence of
sulphuretted and phosphoretted hydrogen, which are always
present in more or less quantity in the latter.
It is a fact that the range of explosibility is wider in
the case of Acetylene than coal gas, but owing to its greater
density and other properties already referred to, the risk is
considerably less.
The actual range of explosibility in mixtures of Acety-
lene and atmospheric air appears to be from a proportion of
five per cent, to sixty per cent, of gas to total volume of
mixture, mixtures having less than five or more than sixty
per cent, being practically non-explosive.
The maximum explosive power — as ascertained bv
NATURE AND PROPERTIES GENERALLY. 31
various authorities — appears to be developed when Acetylene
is in the proportion of from 7-8 to 8' 8 per cent, to the total
volume of gas and air, the variations doubtless being due to
differences in the quality of the gas used.
In the case of coal gas, the explosive range is confined
to mixtures containing from 7'0 per cent, to 3OO per cent, of
gas.
Gas evolved from pure carbide is much less explosive
than that obtained from impure carbide, for the reason that
the latter may contain a certain amount of calcium phosphide,
which on decomposition forms, with the hydrogen of the
water, phosphoretted hydrogen. This gas is spontaneously
inflammable, and may, if sufficient be present, more especially
if some atmospheric air be also present, ignite and explode the
Acetylene. Explosions due to this cause have actually
occurred in two or three instances, attended with more or less
serious consequences.
Acetylene, like other gases, will not " fire back "
through very small apertures or wire gauze, whether the
gas be mixed with air in explosive proportion or not. No
risk of explosion will therefore be incurred if orifices in
burners are not over 0'02 inch in diameter.
Acetylene, being a highly endothermic compound, is
liable when pure, if compressed without at the same time being
cooled, to explode spontaneously and become resolved into its
elements, carbon and hydrogen, even though no oxygen or
atmospheric air be mixed therewith. The most serious
accidents which have yet happened have been attributable to
this property, which is developed when the gas is compressed
to a pressure of 30 Ibs. per square inch and over.
32 ACETYLENE.
Acetylene is soluble in water and many other liquids.
Water absorbs the gas at the rate of 10O1 per cent., i.e., 100
volumes of water will absorb 110 volumes of gas ; but if the
water be saturated with salt or alkali — 20 per cent, by weight
of salt is practically a saturated solution — its absorptive capa-
city is reduced to about 5 per cent.
Paraffin absorbs the gas at the rate of 250 per cent.,
100 volumes of the mineral oil being capable of absorbing 250
volumes of Acetylene.
Acetylene at O° C can be liquified at a pressure of
about 325 Ibs. per square inch, and forms a mobile and highly
refractory liquid much lighter than water, i.e., of a specified
gravity of 0'43. as compared with water.
Acetylene has also a high value as an enricher of coal
gas. Professor Lewes has found that 10 per cent, added
to a poor coal gas raised its light value to 20 candle-power,
and that 20 per cent, of Acetylene added to water gas gave it
an illuminating value of 20 candle power.
Bullier states that 20 per cent, of Acetylene added to
ordinary coal gas (French) increased its illuminating power by
100 per cent.
T. L. Willson has patented a method of enriching and
at the same time dehydrating or drying coal gas : it consists
in passing the gas through vessels containing calcium carbide.
The carbide at once absorbs all moisture from the gas and at
the same time gives off Acetylene, which mingles with the coal
gas and becomes thoroughly mixed therewith. The Acetylene
remains gaseous under all conditions and the enrichment is
therefore permanent.
The process has the merit of extreme simplicity and of
NATURE AND PROPERTIES GENERALLY. 33
insuring the thorough admixture of the gases. But in view of
the fact that the quantity of moisture in suspension in coal gas,
in the form of aqueous vapour, is seldom greater than 0*3 per
cent, by volume, the quantity of Acetylene generated thereby
would be insufficient to improve to any appreciable extent
the illuminating value of the gas.
It has been proved that the admixture of Acetylene
with coal gas in quantities under 10 per cent, effects practically
no improvement in its illuminating power ; it therefore follows
that to enrich coal gas, by the admixture of a minimum of
10 per cent, of Acetylene, about 1 lb. of water per 100 cubic
feet of gas would be necessary.
CHAPTER III.
ACETYLENE AS AN ILLUMINANT.
The acme of perfection in artificial illumination would
be realized if an exact equivalent of solar light could be found,
but that being impossible, the light which most nearly fulfils
the conditions and approaches the quality of sunlight must be
regarded as the best artificial illuminant.
In artificial illumination, by whatever means obtained?
the properties necessary to a realization of the ideal are : —
1. Perfect steadiness.
2. Pure actinic quality.
3. Diffusive power.
4. Low temperature.
Science, so far, has failed to discover a means or source of
artificial light embodying and fully developing all these pro-
perties.
Of all systems of lighting, the incandescent electric is
perhaps the best owing to its very nearly realizing the ideal,
but it fails in regard to the second and third qualities, it being
usually of a yellowish tint, and its diffusion only obtained at a
sacrifice of some of its power by enclosing the filaments in
frosted or slightly opaque bulbs.
The incandescent gas, although an admirable light, and
having considerable power of diffusion, is faulty in the matter
ACETYLENE AS AN ILLUMINANT. 35
of tint, it being usually of a lurid, bluish hue, very trying to
the eyesight, and imparting a ghastly appearance to those of
naturally pale complexion, besides its property of altering the
shades or tones of many colours.
The only light, therefore, which most nearly realizes
the ideal is that afforded by the Acetylene flame, it being at
once steady, practically pure white, diffusive and cool, but the
full development of its properties is dependent upon the
fulfilment of certain conditions in regard to the generation and
combustion of the gas, to insure its being pure, cool and dry,
and the pressure at which it issues from the burners must be
such as to insure admixture with oxygen sufficient for its
complete combustion.
The illuminating power of any hydro-carbon gas is in
direct ratio to the relative proportion of its constituents and
perfect combustion of the carbon is essential to the develop-
ment of its highest degree of luminosity.
Perfect combustion means that all the carbon combines
with oxygen in the process of burning and becomes trans-
formed into carbon-dioxide.
The imperfect combustion of gaseous or other hydro-
carbon illuminants results in reduction of light value and is
attended with liberation of free carbon and emission of
•deleterious products of combustion.
Acetylene having the highest proportion of carbon of
all known gases, it follows that its flame should therefore
possess the highest photometric value, but, at the same time,
the full development of its high illuminating power is depen-
dent upon the complete combustion of its carbon constituent,
and owing to the richness in carbon, its combustion is attended
36 ACETYLENE
with much greater difficulty than is the burning of other
hydro-carbon compounds.
It is owing to its richness in carbon that Acetylene
polymerizes at a comparatively low temperature, and this
property constitutes one of the greatest, if not the chief
difficulty in its use as an illuminant. The heat of the flainer
communicated to the material forming the tip of the burner,
polymerizes some of the gas as it issues through the orifices,
and a carbonaceous deposit is formed therein, restricting the
flow of gas and causing the flame to smoke.
The proper development of the Acetylene flame is
dependent upon the fulfilment of certain chemical and
mechanical conditions if best results are to be attained.
The chemical condition is purity.
The mechanical conditions relate to density, pressure,
and form of burner.
Purity of the gas is the first condition necessary to the
development of the highest light-value of the flame.
The second condition is, that it shall be at its maximum
density, and this is insured by the thorough cooling and
dehydration of the gas.
The pressure should be unvarying, and should be— at
the burners — equivalent to about two and one-half inches of
water, never less than two inches, otherwise the flow of the
gas issuing from the orifices of the burners is not sufficiently
vigorous to insure its intimate admixture with the oxygen of
the air.
The best form of burner is that in which two jets of gas
are caused to impinge upon one another and produce a result-
ing flat flame. This principle is absolutely essential in the
AS AN ILLUMINANT. 37
burning of Acetylene as being the only one by which sufficient
oxygen becomes intimately mingled with the gas to insure its
complete combustion.
The Bray Union jet burner appears to develop the
highest degree of luminosity, the No. 0000 passing about one
cubic foot per hour having given a light value of 55 candle
power. But owing to the tips of these burners becoming
heated by the combustion of the gas taking place almost in
contact therewith, carbonaceous matter quickly accumulates in
the orifices and upon the faces of the burners, which soon
causes the flame to become distorted and to terminate at one
or both outer corners in smoky tips ; but, in view of the small
cost of these burners, their frequent renewal is not a serious
factor in the question of expense.
Owing to the extreme liability of the gas to polymerize,
the heat of combustion communicated to the tips of the burners
causes the deposit of carbonaceous matter within the aper-
g
tures through which it issues, but this contingency is obviated
if actual ignition does not take place in the immediate vicinity
of the orifices.
To overcome the difficulty arising from this cause, and
to obviate the necessity for constant cleaning or changing of
burners, a rather novel type of duplex burner has been
designed, in which, two minute jets issue from orifices inclined
towards one another, set at about one quarter inch apart. The
two jets impinge upon one another, and the full development
of the flame does not take place until, by the impact of the
jets, the gas becomes intimately mixed with air. The orifices
which really govern the flow of the gas are situated at the
bases of small cavities, into which air is admitted through a
3S ACETYLENE
series of holes inclined in the direction of the flow of the gas.
By this arrangement, the jets of gas emerge from the cavities
surrounded by envelopes of air which prevent its. actual
contact with the material of the burner at the point of ignition
and polymerization of the gas is thus avoided.
Burners embodying this principle are supplied by The
Acetylene Illuminating Company, Limited, of London, and
Messrs. Read Holliday and Sons, Limited, of Huddersfield.
The latter firm have recently patented an improved and very
efficient burner of this type which the Author has found to
give perfectly satisfactory results.
A sine qua non in the use of burners of this description
is, that the pressure of the gas is fully up to the necessary
degree, otherwise the jets of gas do not induce adequate
currents of air in the burners to insure best results.
The burners usually employed are of three sizes, and
pass according to pattern, various quantities ranging from
about one-half to one and a-half cubic feet per hour.
The Bray Union jet type are made in sizes designed to
pass, about one and a-half, one, and three-quarter cubic feet
per hour, and are marked 000, 0000, 00000, respectively.
Messrs. Read Holliday and Sons' duplex jet atmos-
pheric burners are numbered "1," " |," and "^"indicating
the quantity of gas designed to pass per hour.
The " Naphey " duplex jet burner supplied by The
Acetylene Illuminating Company, Limited, passes slightly over
one cubic foot per hour, and with pure gas affords a light of
about 50 candle power.
Heating the air before its admixture with the gas, as
in the Pope and Pintsch systems, is said to increase the
AS AN ILLUMINANT.
luminosity of the Acetylene flame by insuring complete com-
bustion of the carbon.
In America, the practice of diluting Acetylene with
air before passing to the burners is in vogue, but it is to be
deprecated owing to the attendant risk of explosion. As stated
in the chapter, on the properties of the gas, mixtures of any
proportion from 5% to 60% being explosive, there is always
the liability of the mixed gas and air " firing back " if proper
precaution be not taken and great care exercised. Dilution
of the gas at the burner is the more desirable and safe method,
and this is made a fait accompli by the atmospheric burners, to
which reference has already been made.
A most interesting experiment was described by Prof.
Lewes, in a lecture before the Institute of Naval Architects,
to determine the relative value of various illuminants, and
with a view to ascertaining the penetrative power of each kind
through fog of average density. By the courtesy of Prof.
Lewes, the Author is enabled to quote the results obtained.
The apparatus employed consisted of a glass cell,
18 inches by 18 inches, by 3 inches, which was filled with
a solution containing 0'1075 gramme of sodium hypo-sulphite
to the litre.
" The illuminating power of the light to be tested
was first read on the photometer in the ordinary way,
and the cell containing the clear liquid was then interposed
half-way between the source of light and the screen, and a
second reading was taken, the difference between the two
giving the amount of light intercepted by the cell and the
liquid it contained. '05 gramme of hydrocloric acid per litre
was then added to the liquid, and the solution was allowed to
40 ACETYLENE
stand until the fine haze of sulphur particles which separated
from the hypo- sulphite had finished forming. When the haze
had completely formed, a third reading with the " fog " cell
interposed was taken on the photometer, and from the three
results, it was possible to deduce the amount of light absorp-
tion due to the haze, as apart from the absorption of the cell
and its liquid contents, the actual results being as follows : —
Percentage of loss of light from various illuminants
in passing through artificial fog solution.
Coal gas 11-1
Oil gas 11-5
Acetylene 14'7
Incandescent gas (Welsbach) 20'8
Electric Arc 26'2
From the data yielded by these experiments, it was found that
less light was absorbed from the yellow coal gas and oil gas
flames than from the whiter Acetylene flame, whilst this, in
turn, was far superior in penetrative power to the Welsbach
incandescent mantle or the light from the electric arc.
These figures merely give the loss of light in passing
through the thickness of fog solution employed, but it is
evident that they will also give approximately the ratio of the
penetrative power of these illuminants in mist-laden air."
The Acetylene light, owing to its actinic quality,
steadiness and intensity, is perhaps the best artificial illuminant
for all photographic purposes, but when used in this connec-
tion it is desirable that it be double reflected or intercepted
by a screen of oiled tissue paper for the purpose of insuring
perfect diffusion, which condition is essential to the attainment
AS AN ILLUMINANT. 41
of best results as owing to its intensity there is a liability of
the illumination of the object being too " hard " and a conse-
quent loss in artistic effect.
The Acetylene light is also eminently suited to all
optical lantern purposes, and is fully equal to lime-light, while
being on the other hand cheaper and easier to manipulate, and
at the same time, more safe and portable. The apparatus
necessary for a two-hour demonstration not being so heavy
nor dangerous as are cylinders of oxygen and hydrogen gas
for affording lime-light for a like period.
Acetylene also possesses an additional advantage in the
fact that it need not be generated until required for use, and
then only in such quantity as may be necessary for a given
length of time.
Another advantage in this connection, when delicately
coloured slides are shewn, being that the light in no way
affects the tone or shade, the full colour-effect is therefore
developed, insuring such slides shewing to best advantage.
Acetylene as an illuminant for cycle lamps is perhaps
an ideal application, and that it finds favour with both
inventors and users is evidenced by the fact that there are now
about a dozen distinct types of lamp, of both British and
foreign origin, in the market, each and all selling freely.
In the application of Acetylene to cycle, carriage or
other portable lamp, two somewhat difficult, although interest-
ing problems present themselves, viz.9 the regulation of the
flow of water to the carbide, and the accommodation of surplus
gas.
The first difficulty has been overcome more or less
successfully by the provision of such means as prevent the
42 ACETYLENE
flow being at a greater rate than that necessary to the pro-
duction of the requisite quantity of gas per minute, or per
hour, and which consists in governing the flow by means of a
delicately adjustable tap or valve, or by causing the water to
pass through a tube practically filled with cotton wick or other
fibrous material by which the flow is restricted to so many
drops per minute, according to the nature or quantity of such
filling.
The second difficulty which may arise in any and every
lamp through variation in .the flow of water, may, if no pro-
vision be made for its escape, set up an undesirable or
dangerous pressure therein. This contingency has been met
in two ways : First, by such arrangement of parts as allow of
the surplus gas forcing back the water, and so finding its way
out through the water vessel ; or Second, by passing the gas
into or through a collapsible rubber bag, which expands to
accommodate gas when the pressure rises to a degree sufficient
to distend the same.
This latter system is faulty, owing to the scope of its
action being limited.
In some lamps examined by the Author, precau-
tionary measures in regard to quantity 'or pressure of gas have
been either overlooked or purposely disregarded as unnecessary,
and the explosion of such a lamp quite recently is within hia
own personal knowledge.
In those lamps in which the water is compelled to perco-
late through fibrous material there is always the liability of such
becoming choked, owing to its acting as a filter and collecting
matter abstracted from the water. The best method, therefore,
of governing the flow would appear to be by means of a
AS AN ILLUMINANT. 43
delicately adjustable valve, which can be so made as to allow
only the requisite quantity of water to pass at its maximum
opening. The opening and closing of such valve in the
starting and stopping of the light tends to keep same free by
the continual disturbance of any deposit or accumulation of
matter due to corrosion.
In applying Acetylene to domestic lighting the ordinary
gas fittings may be used, but should be carefully examined
and tested before admitting the Acetylene thereto, as any
slight leakage, imperceptible in the case of coal gas, is distinctly
noticeable when Acetylene is turned on.
The United States Lighthouse Board have recently
made a trial of Acetylene as a substitute for electricity in
the lighting of buoys. Cylinders of liquified Acetylene,,
provided with valves for reducing the pressure from 600 Ibs.
per square inch to the equivalent of two inches of water, being
located within the buoys. Duplex-jet burners passing one
cubic foot per hour were used, and the light afforded thereby
when concentrated by suitable lense condensers is said to have
been of 250 candle power.
It has been further proved that the illuminating value of
the light given by a 300 candle power Acetylene burner is three
times that of the 200 candle power electric light now in use.
There is also a distinct advantage in the matter of cost,.
an Acetylene-lighted buoy being made for $350, whereas the
electric buoys cost $1,000 each.
Acetylene is now extensively used for train lighting in
France, Germany, and other Continental countries, the gas-
being compressed and stored in cylinders in a manner similar
to method adopted in the case of oil gas.
44 ACETYLENE
Acetylene has also been successfully adapted to Muni-
cipal lighting, the town of Totis, in Hungary, and other
places on the Continent being now lighted throughout by this
illuminant.
Totis was the first town to adopt Acetylene for its
Municipal, commercial and domestic lighting, but towns in
France, Switzerland, and other countries have now adopted
the gas to greater or less extent.
The comparative cost of lighting by various illumin-
.ants, taking ordinary coal gas as the standard of comparison, is
.as follows :
Comparative cost of lighting by various means for an
equal degree of illumination.
Coal gas (ordinary burner) at 2/9 per 1,000 cu. ft. 1/00
Do. (Welsbach Incandescent) ... '47
Petroleum -62
Acetylene (Carbide at £20 per ton) *85
Electricity, at 4£d. per B.T.U 1'68
In the estimate of the cost in the Welsbach system the
amount is for gas only ; if interest upon cost of special fittings
and renewal of mantles be included, the comparative cost
would probably be nearer '75.
Acetylene therefore compares very favourably with
•coal gas, whether under ordinary or the more favourable
incandescent conditions, whereas it is only about half the
cost of electricity at the low rate of 4^d. per B.T.U.
The relative photometric value or light-power of an
illuminant is determined either by comparison with the stand-
ard candle or with another illuminant of similar nature and
of known power.
AS AN ILLUMINANT. 45
The British standard is the sperm candle and is the
amount of light emitted by such medium when consumed at
the rate of about 120 grains per hour.
The apparatus usually employed for computing the
illuminating value of artificial light is known as the Photo-
meter, and consists of a disc of white paper having a "grease
spot" in the centre. It was the invention of the eminent
Runsen, and although it has been varied in form and construc-
tion, in principle it remains the same.
When the degree of illumination on each side of the
disc is equal the whole of the light is reflected therefrom and
the grease spot apparently disappears, but when the illumina-
tion is unequal, the spot at once becomes visible, more
particularly on the side facing the stronger light, owing to the
fact that the greased portion being more translucent than the
ungreased part, some of the light passes through, causing the
greased place to appear of a darker shade.
When a hydro-carbon-name light is to be tested in com-
parison with another of known value, equal flames of each are
arranged so that their centres of greatest luminosity coincide
with the centre of the grease spot on the disc, the light of
known value is then placed at a certain distance from the disc,
and the one to be tested moved either nearer to or farther
from the disc, until the spot disappears ; or the two lights may
be placed in fixed positions and the disc moved relatively
thereto. The difference in the distances of the tested light
and the known one, from the disc, gives the relative light
value of the former as compared with the latter.
When testing gases, the respective pressures thereof,
or quantity burned per hour, must be alike, and the burners-
46 ACETYLENE
of similar pattern and size, and should, after one reading, be
•exchanged and a second reading taken to insure accuracy.
A simple and efficient Photometer may be made in the
following manner.
Take a sheet of good white writing paper having a smooth
but not glossy surface, slightly damp same by pressing between
moistened blotting sheets, and while damp fix between two
flat, hard- wood rings, about six inches diameter inside, and
one inch wide by three-eighths of an inch thick, screwed
together at sufficiently frequent intervals to insure the paper
being clamped equally all around. When dry, mark in
the centre a star or other shaped spot with paraffin wax —
a piece of ordinary paraffin candle answers the purpose — then
warm slightly to melt the wax and cause it to penetrate the
paper. A well denned spot of any form desired is thus
obtained, but care must be exercised in marking the paper not
to apply too much wax, the slightest smear being sufficient.
The warming of the paper should be done over the
-chimney of a clear- burning lamp, so as to avoid heating the
whole of the disc, and at the same time prevent the possibility
of the surface of the paper becoming smoked or otherwise
discoloured.
In use the disc is mounted vertically upon a pillar or
other suitable support, and to obtain accurate results it must
be exactly in the line of the two lights and at right angles
thereto in both the vertical and horizontal planes. Headings
of each light should be taken from each side of the disc, as in
no paper are the surfaces of each sicie exactly alike, and the
difference may cause error if not ascertained by the reversal of
the photometer, and allowance made therefor.
CHAPTER IV.
COMMERCIAL PRODUCTION OF CALCIUM CARBIDE.
The production of Acetylene in large quantities from
Calcium Carbide has only been possible since the discovery
that the desired reaction could be brought about by means of
the electric furnace. The beauty and advantage of the
electro-thermic process, by which practically pure carbide may
be produced from inexpensive materials, are its simplicity and
economy, and that it at the same time insures the production
of a material from which a practically pure gas may be evolved.
The standard of quality in carbide is termed "commer-
cial" purity and means that the percentage of deleterious
matter present is not sufficient to affect the light- value of the
gas evolved therefrom to any appreciable extent, to increase
its explosibility nor render it poisonous, but is at the same
time sufficient to cause the gas to be distinctly odourous.
Acetylene, as evolved from "commercially puTe" carbide,
is therefore practically pure, and its freedom from the im-
purities usually present in other hydro-carbon gases is due to
the fact that the greater part of such deleterious matter is
separated from the elements composing the carbide in the
process of manufacture ; Acetylene is therefore not only the
most pure, but the richest hydro-carbon gas, and consequently
its flame has the highest photometric value or illuminating
power of all known gases.
48 ACETYLENE.
The element calcium is never found in the free state,
but always in combination with one or more other elements.
Combined with oxygen it is the Monoxide or lime (CaO).
Combined with fluorine it is fluor spar (CaF2). Combined
with sulpher and oxygen it is calcium sulphate (CaS04),
known as gypsum, or when combined with carbon and oxygen,
calcium carbonate (CaCO3), found in the form of chalk, lime-
stone and marble.
The formation of calcium carbide by the fusion and
combination of its elements is entirely due to the high tempera-
ture attained in the electric furnace (4,000°C) and not to any
purely electrolitic action or process. The highest temperature
attainable by other known means is that of the oxy-hydrogen
flame, which gives 3,000°C, still 1,000° below the temperature
of the electric arc.
Trials have been made to produce calcium carbide by
means of the oxy-hydrogen furnace, but have so far been un-
successful. The temperature of the electric arc, which is the
highest known temperature, appears therefore to be necessary
to bring about the reaction and consequent combination, by
fusion, of the elements.
Dr. Pictet, the eminent French chemist, who is cele-
brated for his researches in the field of thermo-chemistry, has
patented a process of manufacturing carbide by means of a
combination furnace, in which the materials to be fused into
carbide are raised to the required temperature in three stages.
First by the combustion of carbon and oxygen, then by the
oxy-hydrogen flame, and finally by means of the electric arc,
which completes the process.
The inventor claims that by his method a considerably
COMMERCIAL PRODUCTION OF CALCIUM CARBIDE. 49
increased production of carbide per E.H.P. is effected, as none
of the electric energy is expended in merely raising the
material from the normal temperature to a state of incandes-
cence, the electric current being only required to raise the
temperature of the material to the degree necessary to complete
the operation.
This process is in operation in one or two places on the
Continent, and a company has been formed in this country to-
exploit the Pictet patents for the manufacture of carbide and
for the purification of Acetylene, the latter subject being dealt
with in Chapter VII.
Calcium carbide, as manufactured upon a large scale
at Niagara Falls, at Foyers, in Scotland, and other places, is
made from a mixture of finely powdered lime and coke, in the
proportion of 60 per cent, of the former and 40 per cent, of
the latter, although the resulting carbide consists of 62'5 per
cent, of calcium and 37*5 per cent, of carbon.
The reason for the excess of carbon over the theoreti-
cal quantity requisite is because the coke, being composed of
other elements in combination with the carbon, is not all con-
verted into carbide, and besides, a small proportion of the
carbon being set free, passes away as carbon monoxide.
The mixture of lime and coke is fed into an electric
arc, formed between carbon electrodes, the anode being in the
form of a stout rod suspended over a hearth or slab of carbon,
constituting the cathode.
The material upon entering the electric arc quickly
fuses into a semi-fluid and settles upon the hearth, forming for
the time being the cathode, the real cathode then becoming
merely a connecting link in the circuit.
50 ACETYLENE.
As the fused mass of carbide accumulates, the upper
electrode is raised to maintain the arc, and this adjustment is
necessary every few minutes during a run.
The usual duration of a run is three hours, at the end
of which time a bloom, or ingot, of carbide is formed, the
interior of which is practically pure, but is enveloped in an
outer crust of semi-fused material. The blooms when cool
are broken up and the inferior material, which is of a different
colour to the pure carbide, is picked out. The average yield
per furnace is about '4 ft>. per E.H.P. per hour.
The reaction taking place upon the fusion of the
elements calcium and carbon is expressed by the equation —
CaO + C3 = CaC, -f- CO,
which indicates that the combination of the calcium oxide with
the carbon in forming the carbide is attended by the formation
or liberation of carbon monoxide.
Athough the proportions of lime and coke in the
mixture fed to the furnace may be varied, yet the quantities of
calcium and carbon in the carbide will always be the same,
the combination of the elements with one another being gov-
erned by their chemical affinities.
The mass, or bloom, of carbide as taken from the furnace
usually consists of from 80 to 85 per cent, pure carbide,
the remainder being the outer covering of semi-fused
material which, after being separated from the pure . carbide,
is ground up and again fed into the furnace together with the
fresh material.
The current employed in the electric furnace is of
large quantity, but of low intensity, i.e., the voltage being
usually from 60 to 70, while the amperage is from 1,000 to
COMMERCIAL PRODUCTION OF CALCIUM CARBIDE, ol
2,000, and the yield of pure carbide per E.H.P. per hour
under these conditions has been found to be about 0*4 lb.
Willson states that 1,200 Ibs. of coal dust (anthracite)
and 2,000 Ibs. of powdered quicklime with expenditure of 180
E.H.P. will give in twelve hours 2,000 tbs. of carbide, the
cost of which in America is said to be $15.
L. M. Bullier, a French chemist, an assistant of
Moissan's, has patented a process by which he claims to be
able to produce carbide at a lower temperature than requisite
under ordinary conditions. It consists in mixing a flux with
the lime and carbon. The mixture specified consists of 56
parts quicklime and 36 parts carbon, to which is added 10 per
cent, of fluoride of calcium — fluor spar. This, he claims, makes
the carbide more fluid, and easier to run off from the furnace.
The first works established for the manufacture of
carbide were at Spray, in North Carolina, where Mr. T. L.
Willson had previously erected a plant for the production of
aluminium by electrolitic process, and it was at this place,
while endeavouring to produce metallic calcium by similar
means, that he discovered instead the method of producing
calcium carbide, a material of much greater value and
importance.
In the plant at Spray, the nett E.H.P. at the electrodes
was 169, the current being of 1,310 amperes at 100 volts.
The mixture used consisted of 58 -5 per cent, of lime and 41 '5
per cent, of coke. This plant produced about 92 Ibs. of
carbide per hour, the yield of pure carbide being 9*48 Ibs. per
E.H.P. per day. The production of Acetylene per E.H.P. per
day was 44 cubic feet. The yield from the carbide being at
the rate of 5 cubic feet per lb.
52 ACETYLENE.
There are now said to be eighteen Carbide Factories
throughout the world, the most important being those at
Niagara Falls and at Foyers, in Scotland ; the former owned
by the Acetylene Light, Heat and Power Company, of Phila-
delphia, and the latter owned by the Acetylene Illuminating
Company, Limited, of London.
In the furnaces employed at Niagara the negative
electrodes consist of cast-iron crucibles, carried upon small trucks
or trollies. These are run into the furnaces through openings
in the sides, and when in position beneath the positive electrodes
the leads are connected thereto by means of strong clamps.
The positive electrodes, which are suspended above the
crucibles, are composed of six slabs of carbon, each 4G inches
long, 4 inches thick, by 8 inches wide, clamped together at
their upper ends in a strong cast-iron holder, to which the
copper leads are attached.
In operation the upper electrode is lowered and
contact made with the lower electrode, or crucible ; current is
then turned on and the upper carbon raised, which establishes
the arc. The prepared material is then fed in two streams into
the arc and around the upper electrode to a depth of from two
to three feet. The material passing into the arc is immediately
fused and converted into carbide, which accumulates in the
crucible after the manner of slag. When the crucible is filled
the current is stopped, the trolley disconnected and withdrawn
with its load of crucible and carbide, another trolley and
crucible run into the furnace, and the operation repeated.
Each furnace requires 500 H.P., and the production
is about two and one-half tons (5,000 Ibs.) of carbide per day,
or 10 ibs. per E.H.P.
COMMERCIAL PRODUCTION OF CALCIUM CARBIDE. 53
The average yield of the electric furnaces at Foyers,
is 8'5 Ibs. of pure carbide, per E.H.P. per day, the current
employed being of 4,000 to 5,000 amperes at 55 to 65 volts.
The yield of carbide per E.H.P. per twenty- four hours,
as given by various authorities, varies from 9 Ibs. to 10' 6 Ibs.
9*5 Ibs. may be taken as a possible average.
There are now believed to be four other Carbide
Factories in operation in this country, besides the works at
Foyers, and the production of carbide in Great Britain at the
present time is said to be at the rate of 800 tons per annum.
In Geneva, carbide is manufactured by the Municipal
authorities, the electric light plant being utilized for the pur-
pose during the daytime, when only a small percentage of the
power is required for lighting purposes.
The cost is found to be equivalent to £6 10s. per ton.
The daily production is said to be about six tons.
This method of utilizing generating plant during the
day time might be followed with advantage by other Municipal
or corporate owners of such plant as affording profitable
employment and at the same time equalizing the load.
CHAPTER V.
CALCIUM CARBIDE: ITS COMPOSITION AND
PROPERTIES.
Calcium Carbide is a compound of the elements Cal-
cium and Carbon, and is a crystalline, semi-metallic substance,
having a specified gravity 2*26, its bulk being — theoretically —
12*25 cubic inches per pound. It consists of 62' 5 per cent.
(by weight) of calcium, and 37 '5 per cent of carbon, expressed
by the chemical formula CaC8.
It is of a highly hygroscopic nature, and owing to its
strong affinity for water, both in the vapour and liquid states,
it readily absorbs moisture from the atmosphere, Acetylene
being evolved in the process.
Calcium carbide is not an explosible compound, nor does
it possess any explosive properties, as erroneously attributed to
it. But owing to its peculiar nature not being generally
known and understood, and with a view to insuring public
safety against any possible danger which might arise through
ignorance or carelessness in the carriage or storage thereof, it
is, by a Home Office Order, classed as a dangerous commodity,
and made subject to the same general Regulations as petroleum
and other so-called "dangerous" goods.
Calcium carbide, being produced at the highest known
degree of heat, it is in no way affected by high temperatures.
But when water is applied to it in a closed vessel from
CALCIUM CARBIDE. 55
which the gas has not a free exit, it may set up a pressure at
which it becomes explosive and the heat evolved by the
reaction, if not dissipated, may cause a rise of temperature to
a degree sufficient to ignite the Acetylene : the liability to
ignite spontaneously being greater if there be any sulphur or
phosphorous present.
Acetylene gas is evolved from the carbide by causing
water to act upon it, either by bringing the water to the carbide
or by dropping the carbide into water. In any case, by the
application of water, a double decomposition takes place, the
calcium of the carbide having a stronger affinity for oxygen
than for carbon, separates therefrom, and combines with the
oxygen of the water, forming oxide of calcium, or lime ; on
the other hand, the carbon, having a stronger affinity for
hydrogen than for calcium, separates from it and combines
with the hydrogen of the water, forming Acetylene. The
chemical reaction is expressed by the equation
Ca3C2 + 2H20 = 2Ca(IIO)2 + C2H2.
meaning that the carbide in combining with the water is
resolved into calcium- monoxide and Acetylene.
The production of calcium carbide by the fusion of its
elements being due to the action and expenditure of a consider*
able amount of heat, the resulting material is an endothermic
compound, hence the decomposition of carbide or similar
substances is attended with the liberation of some of the heat
expended in its production, and it is the evolution of this heat
which causes the rise of temperature to take place when water is
brought into contact with the carbide ; but only a certain pro-
portion of the endothermic heat is liberated by this reaction.
The residue remains locked up in the resulting gas until its
56 ACETYLENE.
decomposition is brought about by combustion on combination
with oxygen in the action of burning ; the heat then liberated
raising the particles of carbon in the gas to a high temperature
and corresponding degree of incandescence, hence the luminosity
of the flame.
The theoretical yield of gas from the carbide, if
chemically pure, would be at the rate of 5*8 cubic feet per
pound, but as chemical purity is not attainable when carbide is
manufactured on an industrial scale, the yield from practically
pure commercial carbide is from 5'5 to 5'6 cubic feet per pound.
The average yield when "commercially pure" is 5'2
cubic feet per pound ; but for ordinary purposes it will be
more approximately correct if the yield is assumed as 5 cubic
feet, owing to the presence of a certain proportion of low
quality material and to the hydra tion of the carbide through
exposure to the atmosphere when being broken up arid packed,
or otherwise handled.
The quantity of water actually required or consumed
in the decomposition of carbide is slightly over half a pound,
i.e., *56 Ib. = 15*5 cubic inches per pound, and the combina-
tion of this quantity of water with one pound of carbide, when
practically pure, results in the formation of *40 Ibs. of Acety-
lene (= 5*59 cubic feet), and 1*16 Ibs. of lime, but these
proportions will vary considerably, according to the degree of
purity or quality of the carbide.
Carbide of* calcium manufactured by the Acetylene
Illuminating Company, Limited, at Foyers, is guaranteed to
yield an average of five cubic feet per pound. Carbide
manufactured on the Continent rarely yields above an average
of 4*6 cubic feet per pound.
CALCIUM CARBIDE. 57
Professor Lewes has patented a formula for the pre-
paration of carbide which on decomposition shall give off a gas
burning with a non-smoking flame. The claim is for mixing
with the,- lime and coke or charcoal a certain proportion of
black oxide of manganese.
Gas evolved from this carbide would be diluted with
methane^ or " marsh gas" (CH4), which would serve as a
diluent of the Acetylene, and so tend to make the combustion
thereof more complete by reason of the reduction in the pro-
portion of carbon to hydrogen.
It is possible that the light emitted by the combustion
of the mixed gas would not be so nearly white as from pure
Acetylene, owing to the fact that methane burns with a
yellowish flame.
The Author is not aware as to whether any carbide has
been made according to Professor Lewes' formula, but if
carbide could be formed of such materials as to yield a non-
smoking gas, one of the greatest difficulties in the use of
Acetylene would be at once overcome.
Carbide may be rendered less hygroscopic by saturation
with mineral oil, and a process has been patented for such
treatment thereof, whereby it is claimed that its susceptibility
to the action of water is considerably reduced. It consists in
steeping the carbide, soon after being taken from the furnace
and while still hot, in heavy mineral oil or tar.
The advantage resulting from any method of rendering
the carbide less susceptible to the action of water would be
that the reaction of decomposition, being somewhat retarded
and therefore less vigorous, the temperature would not rise to
so high a degree as when the chemical action is unrestrained.
58 ACETYLENE.
Any process, therefore, which accomplishes this end,
even though imperfectly, would be of advantage, inasmuch as
it tends to insure the evolution of gas in a more pure state and
to prevent possible loss by polymerization, which takes place
in more or less degree, according to the temperature developed
when the same is excessively high.
CHAPTER VI.
GENERATING— SYSTEMS AND APPARATUS.
The simplicity of the process by which calcium carbide
may be decomposed and Acetylene evolved therefrom renders
the generation of this gas a very easy matter, and the apparatus
employed may be of most simple and inexpensive character,
consisting of a Generator and Gasometer, or both may be com-
bined in one.
The process, although the reverse of complex, is at the
same time most wonderful as an example of the marvels of
chemical affinity, the spontaneous reaction set up by the
contact of water with carbide is of a compound character, and
is attended by secondary chemical phenomena. Some know-
ledge, therefore, of the physical conditions involved is most
essential before any experiments are entered upon in this field
of practical chemistry.
Calcium carbide is decomposed by the action of water
thereon, due to the chemical affinity of its elements for the
elemental constituents of water ; and on the other hand, water
is decomposed in the process of combination with the carbide,
the double reaction taking place being represented by the
equation,
Ca2C2 + 2II20 = 2Ca(HO)2 + C2II2.
expressing the fact that the compound of calcium and carbon
60 ACETYLEXE.
combining with water produces two new compounds, oxide of
calcium (lime) and Acetylene.
Calcium carbide being an endothermic compound, con-
siderable heat is evolved during the process of decomposition,
and if there be not sufficient water in the generating apparatus
to dissipate such heat, or, if no provision be made for cooling
the gas, it comes away hot and highly charged with water
vapour which not only reduces its illuminating power, but
may cause trouble by condensation in the pipes.
There are, generally speaking, three systems under
which the gas may be generated ; they may be termed the
" Automatic " or "Dry," the " Non- Automatic " or "Wet,"
and the " Retarded Reaction" system, the latter being a species
of compromise between the automatic and non-automatic
systems. All apparatus embody one or other of these
principles and vary only in arrangement of parts and detail of
construction.
In the automatic system, a certain quantity of carbide
is usually contained in a closed vessel and water admitted
thereto in more or less quantity as gas is required, the flow of
water to the carbide being governed or regulated either by the
quantity or pressure of the gas generated ; the gas as evolved
from the carbide, either flowing into and raising the bell of a
gasometer, or, on the other hand, displacing water and setting
up a hydraulic balance.
In the first case, the increase in quantity does not set
up a correspondingly increased pressure, as once the weight of
the gasometer is balanced by the pressure of the gas, its rising
to accommodate more gas does not, of course, cause any
increase in the pressure thereon.
GENERATING— SYSTEMS AND APPARATUS. 61
In the second case, when the gas is caused to displace a
certain body of water at a given initial pressure, that pressure
is increased as the gas accumulates and displaces a correspond-
ingly increased volume of water, and such pressure continues
to increase until the whole of the balancing water is raised to
a higher level unless such water be allowed to overflow at a
predetermined point at which the maximum desired pressure
is reached.
On the conditions of operation being reversed, i.e.,
when the water is required to displace the gas, the pressure of
the latter decreases as the head of water becomes reduced, so
that with this arrangement there is a constantly varying pres-
sure of gas. This disability is met and to & large extent
neutralized by the use of regulating valves, by which the pres-
sure of the gas, as delivered to the service pipes, is maintained
at an approximately even level, although the pressure in the
generators may vary considerably.
This system has many advocates, and it certainly
possesses the one great advantage of extreme simplicity ; the
compensating medium being a fluid as differing from a
mechanical contrivance, such as a rising and falling bell, the
liability to derangement is consequently reduced to a minimum,
and when gas apparatus is in the charge of persons having no
scientific or mechanical knowledge this is a recommendation.
In actual practice slight variations of pressure are of
little or no consequence as effecting the degree of light, pro-
viding the pressure does not fall much below one and one-half
inches of water, and so reach the smoking point. The
displacement system, therefore, while being perhaps more
suitable for comparatively small installations, it possesses
62 ACETYLENE
features of distinct advantage where domestic servants or other
untechnical or inexperienced persons are concerned.
Where the accommodation of a large and widely -varying
quantity of gas is required the gasometer system would appear
to be most suitable, as providing large storage area, and as
obviating the possibility of any fluctuations of pressure. The
legal restrictions as to pressure practically preclude the
storage of a large quantity of gas under a high head of water.
In all automatic generators the evolution of the gas, in
greater or less quantity, goes on continuously until the carbide
is spent, the whole of the water admitted each time being
absorbed by the carbide. The chemical reaction proceeds
vigorously untiVall free water is absorbed. The undecomposed
carbide, owing to its highly hygroscopic nature, absorbs
moisture from the hydrate, or spent portion of the carbide,
until all water is decomposed, so that, although the actual
contact of the carbide with the water may be intermittent, the
generation of gas is practically continuous, although variable
in quantity. The hydrate, according to the conditions or form
of apparatus, may contain from 10 to 25 per cent, of water,
the greater part of which the undecomposed carbide will, if not
separated therefrom, absorb through the agency of capillary
attraction.
In some forms of apparatus the carbide is contained in
a vessel separated from the gas holder, and as the container of
the latter descends through withdrawal of gas, it operates a
valve by which water is admitted to the carbide, and as the
gas bell again rises it closes the same and stops the flow of
water.
In another form of automatic generator the carbide is
GENERATING— SYSTEMS AND APPARATUS. 63
carried in a species of basket attached to the top of the gas
bell or container, which, on descending, causes the carbide to be
dipped into the water, gas thereupon being evolved raises the
bell and lifts the carbide clear of the water.
In one class of automatic apparatus in which the
pressure of the gas is caused to displace water, the carbide is
usually placed in a tray or basket, located in a certain fixed
position in regard to the water-level, the water being depressed
therefrom or rising thereto as the pressure of the gas increases
or decreases.
In a modified form of apparatus embodying this
principle the water, on rising as the pressure of the gas is
reduced, overflows at a certain point, and is conducted by
suitable means to the vessel containing the carbide, the
normal level of the water in the gas vessel being maintained
by a supply governed by a ball- valve or other equivalent
device.
This general principle has been embodied in apparatus
in a variety of ways by ingenious inventors, but none, so far as
the Author is aware, have overcome the one disadvantage
thereof, the varying pressure.
A circumstance which should not be lost sight of in
the design of the apparatus is the fact that not .only does the
undecomposed carbide, absorb water from the hydrate, but
owing to the heat evolved by the action of decomposition,
some of the water is thereby vapourized and the gas evolved
comes away charged in more or less degree with moisture,
some or all of which may condense upon the undecomposed
carbide and cause evolution of gas, in addition to that due to
the principal reaction, and provision should therefore be made
UNIVERSITY
64 ACETYLENE
for this additional gas, generated after that resulting from the
direct action of the water upon the carbide.
When automatic generators are employed some pro-
vision should be made for cooling the gas before allowing it to
pass into the piping, otherwise it may carry with it more or
less moisture in the form of aqueous vapour, which will con-
dense in the pipes and cause trouble by "popping" or stoppage.
The presence of water vapour in the gas also lowers its illum-
inating value, and at the same time renders the gas more
dangerous, owing to the fact that if ammonia, sulphur or phos-
phorous be derived from the carbide, such water vapour carries
with it the free ammonia, sulphur or phosphorous, or ammonium
sulphide, which tend to render the gas more explosive, at the
same time causing it to give off, in burning, deleterious pro-
ducts of combustion, which would not be the case if the gas
were cool and dry.
Further, if ammonia be present in any appreciable
quantity, it, together with the moisture, may form, on contact
with copper, acetylide of copper, which is an explosive com-
pound, and ignites either through the agency of calorific heat
or that developed by percussive action.
In the "non-automatic" system a quantity of carbide
sufficient to yield a certain volume of gas is put into a vessel
or "generator" containing, comparatively, a large body of
water. The carbide, being immersed in and surrounded by
the water, the gas evolved in bubbling through the same
becomes not only cooled but washed, and thereby freed from
much impurity, which otherwise would remain associated
therewith, unless separated therefrom by purification.
The gas generated on the non-automatic system is
GENERATING— SYSTEMS AND APPARATUS. 65
usually stored in gasometers of capacities designed to hold the
quantity of gas required for use during certain periods.
This system possesses one great advantage in the fact
that all risk of excessive pressure, high temperature, or escape
of gas is avoided. But on the other hand, it has the disadvan-
tage of necessitating, for a given quantity of gas, much more
bulky and costly apparatus than the automatic system,
but where space occupied is not of serious consequence the
non-automatic system insures the preparation of the gas in the
best possible condition for use, i.e., thoroughly cooled and
washed, before passing to the piping and burners.
A system of generating which has much to recommend
it has been patented by Mr. Frederick Dresser, A.M. Inst., C.E.,
and which the Author has termed the " Retarded Reaction '*
process.
It is a species of compromise between the automatic
and non-automatic methods, and consists in enclosing the car-
bide in bags, composed of canvas or other porous material of
somewhat close texture, before immersion in water.
Immediately water penetrates the bag and comes into
contact with the carbide reaction commences and gas is evolved,
which distends the bag and prevents the direct contact of the
water with the carbide, at the same time the bag being
rendered buoyant, it rises up within the generator to a height
determined by the length of a cord or chain to which it is
attached.
The gas, in passing through the interstices of the fabric
of which the bag is composed, is split up into a number of
minute streams and is thereby brought into intimate contact
with the water, which not only insures the thorough cooling,
€6 ACETYLENE.
but; the perfect washing of the gas, and further the direct
contact of the water with the carbide being prevented by the
•distension of the bag, the process of decomposition is thereby
retarded, and the temperature due to the reaction does not rise
to a degree sufficient to affect the gas detrimentally. The
generation of the gas at a comparatively low temperature is
thus insured.
This is a matter of considerable importance not only
as avoiding the contingencies already referred to, but as
obviating the possible polymerization and loss of some of the
gas-
When the decomposition of the carbide is complete,
the bag is withdrawn, bringing away the whole of the
residuum. The bags after being emptied and dried are again
charged ready for use.
This system overcomes one disadvantage of the
ordinary non-automatic process in the fact that the withdrawal
of the residuum of each charge obviates the necessity for the
frequent emptying and cleaning of the .generators.
All generators, whether upon the automatic or non-
automatic systems, should be so designed as to insure the
exclusion of all or nearly all air before the generation of gas
commences, otherwise an explosive mixture may be formed
which may ignite through the issuing gas and air "firing
. back." This, of course, would only be probable if no burners
or those having large orifices were employed.
Another important reason for the exclusion of practi-
cally all air from apparatus before the generation of gas is
commenced, is to obviate the possibility of explosion through
spontaneous ignition of the gas. Some specimens of carbide
GENERATING— SYSTEMS AND APPARATUS. G7
have been found to contain calcium phosphide in sufficient
quantity to cause the Acetylene given off to be impregnated to
such an extent with phosphoretted hydrogen as to ignite
spontaneously in the process of generation.
Although this may be a remote contingency when
" commercially pure " carbide is used, yet the possibility
of such action taking place and constituting a source of danger
is a strong argument in favour of precaution as to exclusion
of air from generators.
Generators of the automatic order should be so designed
and constructed as to avoid any material escape and loss of gas
or introduction of any large quantity of air when removing the
residuum and re-charging with fresh carbide.
Carbide, when decomposed, becomes greater in both
bulk and weight, the increase being about 75 per cent, in
bulk, and (when wet), 25 per cent, in weight, so that ample
provision should be made in automatic generators for this
swelling up, and no carbide vessel should be charged to a
greater extent than 50 per cent, of its total capacity.
The actual quantity of water required and absorbed in
the decomposition of carbide is at the rate of *51b. = 15-5
cubic inches per lb. of carbide.
In non-automatic generators, the vessel should have a
capacity or water area of about one cubic foot per pound of
carbide to be introduced at one time. This proportion insures
the temperature of the water never rising to a degree higher
than that termed " sensibly warm."
Provision should be made for the withdrawal of the
residuum and so obviate the necessity for emptying the
generator, as each time the water is renewed it must be again
68 ACETYLEXE.
saturated with gas before any appreciable quantity is given off r
and the loss of gas thus occasioned may be avoided by atten-
tion to this point.
A quantity of fresh water, equal to the consumption r
should be added each time the generator is re-charged.
CHAPTER VII.
PURIFYING AND DRYING.
Acetylene generated from " Commercial " carbide is
always more or less impure ;' if, therefore, its highest illu-
minating power is to be developed, and at the same time
perfect safety in its use insured, and its combustion is to be
unattended with deleterious products, it should be both purified
and dehydrated or dried.
The gas from British made carbide, although practi-
cally pure, is always impregnated in greater or less proportion
with other compounds, usually sulphuretted and phosphoretted
hydrogen and ammonia, the average amount being about two
per cent.
The presence of sulphuretted hydrogen is due to either
sulphur in the coke or gypsum in the lime, employed in the
manufacture of the carbide, or to both.
The phosphoretted hydrogen is formed by some of the
hydrogen combining with traces of phosphorous in the carbide,
derived from the coke or due to the presence of phosphoric
acid in the lime.
The presence of ammonia in Acetylene is doubtless due
to its formation by the combination of its elements during the
process of decomposition of the carbide by the water and of
the water by the carbide.
70 ACETYLENE.
Ammonia (NII3) is never formed, nor can it be pro-
duced by the direct combination of its elements, nitrogen and
hydrogen, and is only formed upon the decomposition of
compounds containing these elements, when hydrogen in the
nascent condition comes into contact with nitrogen. It is
therefore reasonable "to assume that its formation takes place
simultaneously with the formation of the Acetylene and of the
calcium oxide 'by the combination of the hydrogen of the
water with the nitrogen associated with the carbon of the
carbide.
The greater part of the ammonia thus formed is, how-
ever, retained by the hydrate or spent carbide, its presence
being distinctly discernable in the residuum when being
removed from the generating -apparatus.
Ordinary carburetted hydrogen illuminating gas, as
obtained by the destructive distillation of coal, is always
charged in greater or less degree with sulphuretted-hydrogen,
carbon-dioxide, and ammonia, which compounds are to a large
extent separated therefrom by the process of purification,
which consists in first passing the gas through water, by which
the greater part of the ammonia is absorbed, then, over or
through slaked lime or iron oxide mixed with sawdust, which
absorbs the sulphur and carbonic acid, and finally by passing
the gas through dilute sulphuric acid to remove the remaining
traces of ammonia.
Coal gas, although purified in this manner, is seldom or
never free from the compounds which the purifying process is
designed to eliminate. These compounds form the deleterious
products of combustion, which constitute the principal objection
to coal gas as an illuminant.
PURIFYING AND DRYING. 71
On the other hand Acetylene, owing to the small per-
centage of impurity. present, is more easily and at the same
time perfectly purified, and the separation therefrom of
deleterious elements is not a matter of very great difficulty.
The simplest method by which Acetylene may be
purified is by passing the gas through a mass of broken-up
coke saturated with sulphuric acid. The gas in forcing its
way through the mass is split up into a number of streams,
and is thus brought into intimate contact with the acid which
absorbs not only the ammonia and moisture, but a large pro-
portion of other impurities, if any be present. The gas may
also be freed from ammonia by passing it through coke or
pumice stone saturated with hydrochloric acid.
The coke or other material employed as the vehicle for
the purifying medium should be cleansed periodically by washing
with water, and the same may be re-used any number of times
Gas produced from very impure carbide should also be
passed through or over slaked lime or iron oxide — mixed with
some neutral granular material — for the purpose of separating
therefrom all traces of sulphuretted hydrogen.
To insure the best results being attained, it is desirable
to cool the gas thoroughly before purifying, and thus cause the
moisture in suspension in the form of vapour to condense and
separate from the gas, and by this means reduce the quantity
to be absorbed by the purifying and dehydrating media.
Gases may be dehydrated or dried by passing through
or over highly hygroscopic liquid or solid substances, or
materials. Gas passed through concentrated sulphuric acid
becomes purified and at the same time deprived of all moisture
present owing to the affinity of the acid for water.
72 ACETYLENE.
For merely dehydrating after purification by other
means, crystallized chloride of calcium (Capl,) is perhaps the
best and most simple medium, and when employed, this
material should be broken up into small pieces, such as would
pass through a grid having meshes one inch square ; but for
large quantities of gas the pieces may be of greater size, but
the quantity must be proportionately increased.
The drying material should be contained in a vessel
having a perforated diaphragm or grid a short distance from
the bottom, beneath which the gas is admitted. This is for
the purpose of preventing any moisture of condensation being
absorbed by the dehydrating medium. A tap or other means
should be provided for withdrawing the water from time to
time.
Crystallized chloride of calcium may be revivified and
its hygroscopic properties renewed by heating to the tempera-
ture of redness.
Dr. Pictet recommends passing the gas successively
through a concentrated solution of calcium chloride, then
through sulphuric acid 40 per cent, concentration, then wash-
ing in a solution of lead salts, and finally drying by passing
through crystallized chloride of calcium ; this may be requsite
in the case of very impure gas, but when made from
41 commercially pure " carbide such elaborate treatment is
unnecessary, except when the gas is to be compressed to the
liquid state. Absolute purity is then a sine qua non.
Under ordinary conditions, the gas will be thoroughly
purified by being passed through material saturated with
sulphuric or hydrocloric acid, and afterwards drying by passing
through calcium chloride.
PURIFYING AND DRYING. 73
When gas is to be stored, its purification is most
essential, as the impurities present may cause corrosion of the
metal of the gasometers and other parts of the apparatus, and
danger through leakages arise.
CHAPTER VIII.
STORAGE OF ACETYLENE.
There are certain conditions under which artificial
illumination may be required which, owing to circumstances,
render inconvenient, if not altogether preclude the generation
of gas or electricity when and where required, and it is in
cases of this nature that gas stored in certain quantities in a
concentrated form perhaps most nearly realizes the ideal.
Ordinary coal or oil gas, compressed and stored in steel
cylinders or flasks is, at the present time, being extensively
used for lighting railway carriages, buoys, and for other pur-
poses where a good and portable light is necessitated by the
circumstances of the case.
Acetylene stored in this way and under similar con-
ditions affords illuminating material in both quantity and
quality of light, far in excess of any other hydro-carbon com-
pound, and for that reason it, in comparison with other
illuminating media, possesses a very high value.
The manufacture of Acetylene at central depots and
the supplying of the same in highly concentrated form is in
vogue in America, France and other countries, works having
been established for producing and compressing the gas and
supplying same in bottles or flasks for train lighting and
other purposes.
STORAGE OF ACETYLENE.
Although gas or other highly expansive body stored
under great pressure is to some extent undesirable, owing to
the ever-present risk of explosion, yet the system, in the case
of gas for illuminating purposes, possesses such great advan-
tages that, notwithstanding the objection thereto on the score
of risk, the system is much in favour, and the dangers thereof
are more problematical than real. When it is considered that
the flasks and cylinders employed are made of a strength
sufficient to withstand as much as ten times the strain to which
they are subject in practice, and that, in addition thereto, they
are perhaps more severely tested than any other commercial
article, the probability of accident through bursting is most
remote.
The most serious accidents which have so far occurred
through explosions of Acetylene have been in connection with
the compression of the gas, but at the same time have been
traceable to impurity of the gas, to want of knowledge of its
properties when under pressure, or to neglect of proper pre-
caution.
There are three methods or systems under which
Acetylene may be stored —
1. — In the gaseous condition.
2. — By absorption in neutral fluid.
3. — By liquif action.
The relative space occupied by a given volume stored
under the three conditions being, approximately : —
In gaseous conditions ... 2000 '0
By absorption in liquid ... 6*6
In liquified condition ... 5'0
76 ACETYLENE.
The gaseous condition being assumed as at usual
pressures up to the equivalent of three inches of water. But at
whatever pressure stored, the space occupied by a given volume
is in the inverse ratio to the pressure.
The limit of pressure in generators and gasometers
fixed by the Home Office Regulations as to storage and carriage
of Acetylene is 1^ atmospheres = '73 Ib. per square inch
above atmosphere, gas stored at pressures over this limit being
subject to the provisions of the Explosives Act.
When Acetylene is stored in the gaseous condition in
gasometers at ordinary pressures, the holders should be con-
structed with internal domes so that the water area exposed
to the gas may be as small as possible, for the purpose of
avoiding loss of gas by absorption. The liquid employed for
sealing the gas bell should be a saturated salt or alkaline
solution, for the reason that such solutions absorb little or no
gas, and do not freeze except at extremely low temperatures ;
stoppage of apparatus by freezing in cold weather is thus
avoided.
Acetylene may conveniently be stored by absorption in
acetone and other liquids, and its explosive properties are
greatly decreased, if not entirely destroyed, by solution in a
neutral fluid.
The co-efficient of expansion of Acetylene solution is
much lower than that of liquified Acetylene, so that vessels in
which such solutions are stored may be filled, the risk of
accident through bursting being relatively less.
The fluid capable of absorbing tlve largest amount of
Acetylene, and which again gives up practically the whole
volume is Acetone (C3TIGO). It is a limpid, mobile, combust-
STORAGE OF ACETYLENE. 77
ible liquid, of a specific gravity of '814. It burns with a
white, smokeless flame, and even when mixed with an equal
volume of water is still inflammable.
At ordinary atmospheric pressure and at a temperature
of 27° C, acetone will absorb twenty-five times its volume of
Acetylene, and its absorptive capacity increases nearly in direct
ratio to pressure. At a pressure of 175 to 180 Ibs. per square
inch, one volume of acetone will absorb 300 volumes of
Acetylene. On relieving the pressure the gas passes out, and
the exhausted liquid can again be charged.
The absorptive capacity of acetone decreases in the
inverse ratio to its temperature, so that at 57°C it only absorbs
about half the quantity it is capable of absorbing at 27°C.
Acetylene may be liquified at pressures varying ac-
cording to temperature from 325 Ibs. per square inch at 0°C
to 700 Ibs. per square inch at 35° C, the necessary pressure in-
creasing in proportion to rise of temperature. Under these
conditions it becomes a mobile, highly refractory liquid of a
specific gravity of 0'43, weighing 28 '15 Ibs. per cubic foot,,
the ratio of the gaseous to the liquid conditon being 396:1.
Although the system possesses great advantages, the
danger is also great, as unless the gas be perfectly pure and
the temperature kept at or below the freezing point of water
there is a risk of explosion during the process of compression,
and it is a fact that the majority of the accidents which have
occurred through explosions of Acetylene have been in con-
nection with the compression and liquification of the gas.
For ship and buoy lighting storage in the liquified
form is imperative, owing to the conditions rendering the
employment of generating apparatus or gasometers practically^
78 ACETYLEXE.
impossible; the system is therefore peculiaily applicable and
advantageous in these cases. Although the tendency of
Acetylene in this condition to expand under the influence of
heat, causes high pressures to be set up in the cylinders or
flasks in which it is stored, yet if proper precaution be taken
to keep them at a low temperature the danger is remote.
At temperatures up to 83°C the pressure in the
cylinders would not exceed 700 Ibs. per square inch, and even
when the temperature is raised to 46°C the pressure does not
exceed 1,000 Ibs. per square inch. So that when it is con-
sidered that flasks or cylinders used for the storage of com-
pressed gas are usually tested at pressures up to 3,000 hbs. per
square inch, it is obvious that a good margin of safety exists.
In comparison with the storage of certain quantities of
gas under the foregoing conditions, the quantity of carbide
necessary to yield say 2000 cubic feet of gas — at the rate of
1 ib. per 5 cubic feet — would be 400 Ibs., having a bulk
measurement of but slightly over 3 cubic feet. But, as a set-off
against this, the apparatus necessary to the evolution of the
gas would, together with the carbide, occupy considerably
more space for a given quantity than the gas in the liquified
condition, and further, the difficulties and dangers attending
the generation of gas on shipboard, more particularly in rough
weather, point to the employment of Acetylene in the com-
pressed form as the best under the circumstances.
CHAPTER IX.
ACETYLENE AS A MOTIVE POWER.
Acetylene, although applicable as a motive power, is
not an economical source of energy, and if the combustion be at
all imperfect, difficulties arise "owing to deposit of carbonaceous
matter in the cylinders and passages of engines in which used.
The thermo-dynamic value of Acetylene compared
with coal gas has been ascertained to be from 2 -7:1 to 2'8:1.
But, in view of the fact that the cost of this gas is, at the
present price of carbide, about 34/- per 1,000 cubic feet, and
that an equivalent dynamic value — at the higher ratio — in
coal gas would cost only about 7/6, there is little likelihood of
Acetylene being employed for power purposes, while the price
of carbide remains at £20 per ton.
But, although Acetylene would be a comparatively
costly agent for the development of dynamic energy, yet,
some particulars of the results of experiments conducted for
the purpose of determining its dynamic value are of interest
as affording data enabling comparison of the thermo-dynamic
value of Acetylene with that of coal, coal gas, and mineral oil.
Experiments in the use of Acetylene for motors have
been made by M. Ravel, in France, who found that 11*45
cubic feet of the gas developed one I.H.P. per hour, whereas
34'4 cubic feet of coal gas was required for an equal power in
the same engine.
80 ACETYLENE
These figures would appear to prove that Acetylene
possesea a thermo-dynamic value compared with coal gas of
3:1, but this result was obtained with doubtless practically
pure Acetylene, as against a possibly low quality coal gas.
34'4 cubic feet may be necessary, in the case of French
gas, for the development of one I.H.P. per hour, but that
quantity, compared with the consumption of British gas in the
latest types of British-made engines, is excessively high. The
average consumption per horse-power-hour in this country
being from about 20 cubic feet in small engines to 1 6 cubic feet
in larger engines.
Experiments upon a somewhat larger scale made by
Herr Von Ihering, in Germany, shewed Acetylene to have a
thermo-dynamic value of 2*7 as compared with coal gas and
from the conditions under which the experiments were made
and the results obtained, and taking into consideration the
nature and properties of Acetylene, it is reasonable to suppose
that in proportion as the size of the motor is increased, Acety-
lene should give relatively more favourable results and that a
value of 3:1, as compared with coal gas might be realized.
Acetylene has been employed experimentally in the
engine of a motor cycle, a mixture containing but six per cent,
of gas being used. The results are said to have been very
satisfactory.
Liquified Acetylene would appear to be particularly
suitable as a motive power for light vehicles owing to the
small bulk and weight of a comparatively large quantity.
The low ignition temperature of Acetylene and air
mixtures (480°C), was found to make the firing of the charge
an easier matter than in the case of coal gas. But it was also
FAS A MOTIVE POWEB. 81
found that the suddenness of the explosion— owing to the rapidity
of the flame propagation — rendered it difficult to utilize the
whole of the energy capable of being developed by a given
volume of Acetylene.
The best explosive effect, i.e., the highest pressure
developed by detonation of a certain volume of mixed gas and
air is produced when the gas is about 8*0 per cent, of such
volume, but'the best~effect in an engine has been found to be
realized when the gas bears a proportion of 6 '8 to 7'0 per
cent, to the total volume, as with this percentage the propa-
gation of the flame of ignition is not so rapid as with mixtures
having higher proportions of .gas, hence the explosion is not of
so sudden a character and the impetus given to the piston is
consequently more effective owing to the duration of the ex-
plosion being greater than when the mixture contains a higher
percentage of gas.
The calorific value of Acetylene, per volume, when
burned on the Bunsen system is about 2 '5 times that of
ordinary coal gas.
The calorific values of various heat giving agents per
pound, expressed in British Thermal Units, also their relative
values, taking coal as the standard, are as follows : —
Relative
B.T.U. per pouud. Value.
1. —Coal '(good steam) ... 14,500 ... I'OO
2.— Coal Gas 17,800 ... 1'22
3.— Petroleum 20,500 ... 1-41
4.— Acetylene 21,170 ... 1'46
Owing to the higher specific gravity of Acetylene the
number of cubic feet per pound is only 13*45, as compared
82 ACETYLENE.
with 28' 79 for coal gas, hence the apparently slight difference
in calorific value per pound.
The British Thermal Unit is the standard of calorific
value, and signifies the amount of heat necessary to raise one
pound of water 1° F., i.e., from 39- 1° to 40- 1° F., deduced
from Joule's determination of the mechanical equivalent of
heat.
Calcium carbide and liquified Acetylene have each been
suggested as fuel for steamships, and having regard to the
calorific value of the latter, compared with coal and petroleum,
it would appear to have advantages. The gas in the carbide
form is out of the question, its heat value — on a basis of five
cubic feet per Ib. — being but 7,870 B.T.U. per ft).
In view of the present cost of carbide, it would be idle
to discuss the application of Acetylene to motive power pur-
poses, either ashore or afloat ; but from the data herein given,
the relative calorific value of Acetylene in comparison with
other heat-giving agents may be estimated, and in the event of
the price of carbide being reduced to a point at which the use
of Acetylene would be economical, the figures may prove
useful.
CHAPTER X.
ACETYLENE APPLIED TO ARTS AND INDUSTRIES.
The possibility of forming organic compounds from
inorganic originals or bases was first proved by the discovery
that cyanogen (CN) could be produced synthetically, and con-
stituted the first link in the establishment of the relationship
now known to exist between organic and inorganic compounds.
This was followed by the discovery that Ethine or
Acetylene could be produced synthetically by the direct com-
bination of its elements and this latter discovery formed
the explanation of one of the most wonderful of natural
phenomena, throwing, as it did, considerable light upon those
mysterious workings of Nature by which vast stores of both
liquid and gaseous hydro-carbons have been built up, and
which have proved of such great value to mankind.
Prior to this discovery hydro-carbon compounds were
thought to be obtainable only by the decomposition of com-
pounds of organic origin.
The possibility of producing cyanogen and ethine and
from them a wide range of organic compounds has effectually
removed the line of demarkation between organic and inorganic
chemistry, previously thought to exist.
The varying proportions in which carbon and hydrogen
combine is almost infinite, each one forming a distinct com-
pound, differing from other compounds of the same elements.
84 ACETYLENE
The derivatives of the hydro-carbon compounds are
also practically infinite in their number and variety, carbon
and hydrogen possessing affinities for and combining freely
with a large number of other elements.
Acetylene, being a compound of hydrogen and carbon,
possessing properties other than those of high photometric
value as an illuminant and calorific value as a source of energy,
its possible industrial applications are many and various.
From Acetylene a large number of other hydro-carbon
compounds may be derived by different methods of treatment
and by the employment of various chemical re-agents, it is thus
possible to obtain, through its agency, compounds of an
organic nature from purely inorganic mineral substances.
Acetylene, on being heated in confinement to the tem-
perature of dull redness, is converted into Benzene, C6H6.
Benzene, again being heated in confinement to tempera-
ture of bright redness, is transformed into Naphthaline, C10H8,
from which — by combination with Bromide, Chlorine and
other elements — may be produced an infinite variety of com-
pounds, all of an interesting nature scientifically, some having
a high value commercially, not the least of which being the
dye-stuffs, "Magdala Red" and "Campobello Yellow."
Acetylene may also be converted, by combination with
nascent hydrogen, into Ethylene (C2H4), which, on being dis-
solved in sulphuric acid, forms Ethylsulphuric acid (C2HGSO4),
which, upon being distilled with water, yields Ethyl-alcohol,
or "Alcohol."
Alcohol, C2H60, as indicated by the formula, is a com-
pound of carbon, hydrogen and oxygen. Acetylene consisting
of the first two elements, it only remains to add the third,
APPLIED TO ARTS AND INDUSTRIES. 85
oxygen, together with the additional quantity of hydrogen
requisite, and the synthesis of alcohol is thereby effected.
The production of alcohol, practically direct from
calcium carbide, may be effected in the following manner : —
Calcium carbide and metallic zinc are treated together
with water, acidulated with sulphuric acid. Acetylene and
hydrogen are thus evolved together, and the latter, being in
the nascent state, readily combines with the Acetylene.
This combination results in the production of Ethylene
C2H4. This gas, upon being passed into a vessel containing
concentrated sulphuric acid (H2SO4), combines in certain pro-
portion with both the oxygen and hydrogen thereof, forming
ethylsulphuric acid (C2H6SO4). This compound, upon distilla-
tion with water, is resolved into alcohol and sulphuric acid,
the former being obtained by condensation of the vapour by
passing same through a coil, surrounded with cold water in the
usual manner.
It will thus be seen that the synthetic production of
Acetylene on a commercial scale is likely to effect, beneficially,
various industries, and not the least will be the manufacture
of spirituous liquors, which will be free from those dangerous
essences which are said to be always present in alcohol obtained
from vegetable sources.
The future prospects of Acetylene as an illuminant,
and as applied to arts and manufactures will be largely dependent
upon the production of calcium carbide at a price which will
permit of and insure economy in its use. When it is considered
that the actual' cost of production of this commodity is about
one-third of its selling price, the possibility of the present mar-
ket price being considerably reduced is more than prospective.
ACETYLENE
The cost of Acetylene for lighting purposes, as com-
pared with the cost of coal gas, is easily computed. The
present price of carbide is £20 per ton = 20/- per cwt.
Assuming an average yield of five cubic feet per lb., the cost
of Acetylene, at this rate, would be 35s. 8^d. per 1,000 cubic
feet. To compare the cost with that of coal gas, this amount
must be divided by, at least, fifteen, which gives 2s. 4^d. as
the cost of an equivalent in candle-power hours. This com-
pares favourably with 2s. 9d., the present price of coal gas in
Liverpool, and which price may be regarded as a fair average.
In view of the fact, that a number of manufactories
are now producing calcium carbide in more or less quantities,
and the prospect of the price being reduced in the near future.
Acetylene may yet prove to be the most economical of all
illuminants, and its application to various industrial purposes
become a fait accompli.
HOME OFFICE AND FIRE INSURANCE
REGULATIONS.
Calcium carbide having been classed as a " Dangerous"
commodity, it has been made subject to the provisions of the
Petroleum Acts and to the general Home Office Regulations
governing the storage and conveyance of same, in addition to
which, an Order in Council was issued in February, 1897,
containing special Regulations and Provisions regarding calcium
carbide, and empowering Municipal Authorities to issue Local
Regulations to be applicable within the areas over which they
hold jurisdiction.
Calcium carbide, in quantities up to five pounds, may be
stored without a license, providing that the same be kept in
APPLIED TO ARTS AND INDUSTRIES. 87
lots of one pound or under in separate air-tight metal recep-
tacles.
If it is desired to store more than five pounds in one
place, a license to do so must be obtained, the cost of which is
five shillings.
These licenses are issued by the Local Authorities, are
granted for periods of twelve months, and the conditions
thereof are according to the Home Office Regulations under
the Petroleum Acts.
Abstracts of the Local Regulations are issued by the
Municipal Authorities of all large towns, and copies thereof
may be obtained gratis.
In Liverpool, copies of the Local Regulations may be
procured on application at the Licensing Department, Muni-
cipal Offices, Dale Street.
The Fire Insurance Regulations as to location of
Acetylene Gas Apparatus, and storage of the gas and of
calcium carbide, which were at one time unreasonably
stringent, having now been modified, small generating appara-
tus, in which the charge of carbide does not exceed two pounds
is now permitted within insured premises, providing proper
precautions be taken to prevent leakage, and provision made
for the escape of surplus gas into the outer atmosphere.
Large apparatus must be placed outside the insured
premises, and a cut-off or stop tap must be provided in the
piping conveying the gas to the insured buildings, such tap to
be placed as near as possible to the generating or storage ap-
paratus.
Provision must also be made for allowing surplus gas
88 ACETYLENE.
to escape into the outer atmosphere should the pressure rise
to a higher degree than four ounces per square inch.
The storage of liquified Acetylene is absolutely pro-
hibited upon insured premises, and insurance companies are
agreed not to admit liability for damage due to the explosion
of Acetylene gas occurring elsewhere than in the building
which is, or the contents of which are the subject of the in-
surance.
The future prospects of Acetylene will largely depend
upon two conditions or factors, i.e., the price of carbide and
the amount of interest taken in its application, and intelligence
exercised in its use.
That the price of carbide will be considerably reduced
in the near future is more than probable, but whether such
enthusiasm will be aroused in regard to Acetylene as will lead
to a general desire for a better knowledge of its properties, and
thereby a modification of the prejudice which still obtains,
remains to be seen. But there is little doubt that, with a
better understanding of the subject, a further relaxation of
both the Legislative and Fire Insurance restrictions would
follow as a natural consequence.
Even under present conditions, Acetylene is proving a
great boon in its various applications, and there is every pro-
bability of its being more generally adopted and valued at its
true worth, as its advantages become better known,
ADVERTISEMENTS.
VIIT.
flCETYIiEflE GAS RPPflfrflTUS
EXLEY & CO/S
TYPE " B" IHSTALLATION w.™ 2 or 4 GENERATORS
ACKNOWLEDOKI) TO RE THE
Simplest and Most Efficient in the Market*
Each Generator works independently, another coming into
operation automatically when one is exhausted.
Our Generators
are in use in all
parts of this
Country and the
Colonies.
Highest Testimonials
have been received.
Any one can
manage
our Machines
after reading
printed instructions
supplied
therewith.
Working Pressure from 8 ins. to 10 ins. water displacement,
or under \ Ib. per square inch.
Gas Cooled and Purified before entering service pipes.
EXLEY & CO., Original Patentees & Makers,
Byram St., HUDDERSFIELD,
IX
CE
An
Ret
If
Gu
THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW
AN INITIAL FINE OP 25 CENTS
WILL BE ASSESSED FOR FAILURE TO RETURN
THIS BOOK ON THE DATE DUE. THE PENALTY
WILL INCREASE TO SO CENTS ON THE FOURTH
DAY AND TO $1.OO ON THE SEVENTH DAY
OVERDUE.
13 1935
APR 22 1943
JAN 18 1944
JUL 27 1944
UEC
RtC'D LC
APR 1G 1957
ITlAi
TES
iplete
tions
:les,
•—-*-" interns
"*•
les,
tc.
LD 21-1007n-8,
... , s.w.
YB 15419
ADVERTISEMENTS.
The
complies with the
cannot accumulp
has no screws
A.C.T.
Lamp
regu! > th
has a ge'
is the' .
as 76 Z,
ir
The
T£-
YCLES,
>RIAQES,
'ORS or
YACHTS.
Cements.
.np.
the market.
An f is the ligh
.U. I • is clipped
Dunces.
.uminium.
• sting Oil Lamps,
is the lightest, cheapest, and safest in the market.
to the frame, like a pump.
will give Gas for six hours.
(j6B6r<uOn wj|| burn any sized Carbide from lump to dust.
Note
— The combined weight i>f the Generator and Lamp is less than the ordinary Oil Lamp
Price, LAMP
GENERATOR
In Nickel, 56
10/6
In Aluminium, 6/-
12/-
Further particulars will be furnished by —
The Acetylene Gas Light, Power, & Calcium Carbide Co., Ltd.
18, Ironmonger Lane, LONDON, E.G.
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