[1] _Harmonie universelle_ (Paris, 1636), bk. v. pp. 232-237.
[2] See Sir Thomas Browne's Works, vol. i. p. 206.
[3] See Capt. C.R. Day, _Descriptive Catalogue of Musical
Instruments_ (London, 1891), pp. 18-22 and pl. 4; also _Complete
Instructions for the Double Flageolet_ (London, 1825); and _The
Preceptor, or a Key to the Double Flageolet_ (London, 1815).
FLAGSHIP, the vessel in a fleet which carries the flag, the symbol of
authority of an admiral.
FLAHAUT DE LA BILLARDERIE, AUGUSTE CHARLES JOSEPH, COMTE DE (1785-1870),
French general and statesman, son of Alexandre Sebastien de Flahaut de
la Billarderie, comte de Flahaut, beheaded at Arras in February 1793,
and his wife Adelaide Filleul, afterwards Mme de Souza (q.v.), was born
in Paris on the 21st of April 1785. Charles de Flahaut was generally
recognized to be the offspring of his mother's liaison with Talleyrand,
with whom he was closely connected throughout his life. His mother took
him with her into exile in 1792, and they remained abroad until 1798. He
entered the army as a volunteer in 1800, and received his commission
after the battle of Marengo. He became aide-de-camp to Murat, and was
wounded at the battle of Landbach in 1805. At Warsaw he met Anne
Poniatowski, Countess Potocka, with whom he rapidly became intimate.
After the battle of Friedland he received the Legion of Honour, and
returned to Paris in 1807. He served in Spain in 1808, and then in
Germany. Meanwhile the Countess Potocka had established herself in
Paris, but Charles de Flahaut had by this time entered on his liaison
with Hortense de Beauharnais, queen of Holland. The birth of their son
was registered in Paris on the 21st of October 1811 as Charles Auguste
Louis Joseph Demorny, known later as the due de Morny. Flahaut fought
with distinction in the Russian campaign of 1812, and in 1813 became
general of brigade, aide-de-camp to the emperor, and, after the battle
of Leipzig, general of division. After Napoleon's abdication in 1814 he
submitted to the new government, but was placed on the retired list in
September. He was assiduous in his attendance on Queen Hortense until
the Hundred Days brought him into active service again. A mission to
Vienna to secure the return of Marie Louise resulted in failure. He was
present at Waterloo, and afterwards sought to place Napoleon II. on the
throne. He was saved from exile by Talleyrand's influence, but was
placed under police surveillance. Presently he elected to retire to
Germany, and thence to England, where he married Margaret, daughter of
Admiral George Keith Elphinstone, Lord Keith, and after the latter's
death Baroness Keith in her own right. The French ambassador opposed the
marriage, and Flahaut resigned his commission. His eldest daughter,
Emily Jane, married Henry, 4th marquess of Lansdowne. The Flahauts
returned to France in 1827, and in 1830 Louis Philippe gave the count
the grade of lieutenant-general and made him a peer of France. He
remained intimately associated with Talleyrand's policy, and was, for a
short time in 1831, ambassador at Berlin. He was afterwards attached to
the household of the duke of Orleans, and in 1841 was sent as ambassador
to Vienna, where he remained until 1848, when he was dismissed and
retired from the army. After the _coup d'etat_ of 1851 he was again
actively employed, and from 1860 to 1862 was ambassador at the court of
St James's. He died on the 1st of September 1870. The comte de Flahaut
is perhaps better remembered for his exploits in gallantry, and the
elegant manners in which he had been carefully trained by his mother,
than for his public services, which were not, however, so inconsiderable
as they have sometimes been represented to be.
See A. de Haricourt, _Madame de Souza et sa famille_ (1907).
FLAIL (from Lat. _flagellum_, a whip or scourge, but used in the Vulgate
in the sense of "flail"; the word appears in Dutch _vlegel_, Ger.
_Flegel_, and Fr. _fleau_), a farm hand-implement formerly used for
threshing corn. It consists of a short thick club called a "swingle" or
"swipple" attached by a rope or leather thong to a wooden handle in such
a manner as to enable it to swing freely. The "flail" was a weapon used
for military purposes in the middle ages. It was made in the same way as
a threshing-flail but much stronger and furnished with iron spikes. It
also took the form of a chain with a spiked iron ball at one end
swinging free on a wooden or iron handle. This weapon was known as the
"morning star" or "holy water sprinkler." During the panic over the
Popish plot in England from 1678 to 1681, clubs, known as "Protestant
flails," were carried by alarmed Protestants (see GREEN RIBBON CLUB).
FLAMBARD, RANULF, or RALPH (d. 1128), bishop of Durham and chief
minister of William Rufus, was the son of a Norman parish priest who
belonged to the diocese of Bayeux. Migrating at an early age to England,
the young Ranulf entered the chancery of William I. and became
conspicuous as a courtier. He was disliked by the barons, who nicknamed
him Flambard in reference to his talents as a mischief-maker; but he
acquired the reputation of an acute financier and appears to have played
an important part in the compilation of the Domesday survey. In that
record he is mentioned as a clerk by profession, and as holding land
both in Hants and Oxfordshire. Before the death of the old king he
became chaplain to Maurice, bishop of London, under whom he had formerly
served in the chancery. But early in the next reign Ranulf returned to
the royal service. He is usually described as the chaplain of Rufus; he
seems in that capacity to have been the head of the chancery and the
custodian of the great seal. But he is also called treasurer; and there
can be no doubt that his services were chiefly of a fiscal character.
His name is regularly connected by the chroniclers with the ingenious
methods of extortion from which all classes suffered between 1087 and
1100. He profited largely by the tyranny of Rufus, farming for the king
a large proportion of the ecclesiastical preferments which were
illegally kept vacant, and obtaining for himself the wealthy see of
Durham (1099). His fortunes suffered an eclipse upon the accession of
Henry I., by whom he was imprisoned in deference to the popular outcry.
A bishop, however, was an inconvenient prisoner, and Flambard soon
succeeded in effecting his escape from the Tower of London. A popular
legend represents the bishop as descending from the window of his cell
by a rope which friends had conveyed to him in a cask of wine. He took
refuge with Robert Curthose in Normandy and became one of the advisers
who pressed the duke to dispute the crown of England with his younger
brother; Robert rewarded the bishop by entrusting him with the
administration of the see of Lisieux. After the victory of Tinchebrai
(1106) the bishop was among the first to make his peace with Henry, and
was allowed to return to his English see. At Durham he passed the
remainder of his life. His private life was lax; he had at least two
sons, for whom he purchased benefices before they had entered on their
teens; and scandalous tales are told of the entertainments with which he
enlivened his seclusion. But he distinguished himself, even among the
bishops of that age, as a builder and a pious founder. He all but
completed the cathedral which his predecessor, William of St Carilef,
had begun; fortified Durham; built Norham Castle; founded the priory of
Mottisfout and endowed the college of Christchurch, Hampshire. As a
politician he ended his career with his submission to Henry, who found
in Roger of Salisbury a financier not less able and infinitely more
acceptable to the nation. Ranulf died on the 5th of September 1128.
See Orderic Vitalis, _Historia ecclesiastica_, vols. iii. and iv. (ed.
le Prevost, Paris, 1845); the first continuation of Symeon's _Historia
Ecclesiae Dunelmensis_ (Rolls ed., 1882); William of Malmesbury in the
_Gesta pontificum_ (Rolls ed., 1870); and the _Peterborough Chronicle_
(Rolls ed., 1861). Of modern writers E.A. Freeman in his _William
Rufus_ (Oxford, 1882) gives the fullest account. See also T.A. Archer
in the _English Historical Review_, ii. p. 103; W. Stubbs's
_Constitutional History of England_, vol. i. (Oxford, 1897); J.H.
Round's _Feudal England_ (London, 1895). (H. W. C. D.)
FLAMBOROUGH HEAD, a promontory on the Yorkshire coast of England,
between the Filey and Bridlington bays of the North Sea. It is a lofty
chalk headland, and the resistance it offers to the action of the waves
may be well judged by contrast with the low coast of Holderness to the
south. The cliffs of the Head, however, are pierced with caverns and
fringed with rocks of fantastic outline. Remarkable contortion of strata
is seen at various points in the chalk. Sea-birds breed abundantly on
the cliffs. A lighthouse marks the point, in 54 deg. 7' N., 0 deg. 5' W.
FLAMBOYANT STYLE, the term given to the phase of Gothic architecture in
France which corresponds in period to the Perpendicular style. The word
literally means "flowing" or "flaming," in consequence of the
resemblance to the curved lines of flame in window tracery. The earliest
examples of flowing tracery are found in England in the later phases of
the Decorated style, where, in consequence of the omission of the
enclosing circles of the tracery, the carrying through of the foliations
resulted in a curve of contrary flexure of ogee form and hence the term
flowing tracery. In the minster and the church of St Mary at Beverley,
dating from 1320 and 1330, are the earliest examples in England; in
France its first employment dates from about 1460, and it is now
generally agreed that the flamboyant style was introduced from English
sources. One of the chief characteristics of the flamboyant style in
France is that known as "interpenetration," in which the base mouldings
of one shaft are penetrated by those of a second shaft of which the
faces are set diagonally. This interpenetration, which was in a sense a
_tour de force_ of French masons, was carried to such an extent that in
a lofty rood-screen the mouldings penetrating the base-mould would be
found to be those of a diagonal buttress situated 20 to 30 ft. above it.
It was not limited, however, to internal work; in late 15th and early
16th century ecclesiastical architecture it is found on the facades of
some French cathedrals, and often on the outside of chapels added in
later times.
FLAME (Lat. _flamma_; the root _flag_-appears in _flagrare_, to burn,
blaze, and Gr. [Greek: phlegein]). There is no strict scientific
definition of flame, but for the purpose of this article it will be
regarded as a name for gas which is temporarily luminous in consequence
of chemical action. It is well known that the luminosity of gases can be
induced by the electrical discharge, and with rapidly alternating
high-tension discharges in air an oxygen-nitrogen flame is produced
which is long and flickering, can be blown out, yields nitrogen
peroxide, and is in fact indistinguishable from an ordinary flame except
by its electrical mode of maintenance. The term "flame" is also applied
to solar protuberances, which, according to the common view, consist of
gases whose glow is of a purely thermal origin. Even with the restricted
definition given above, difficulties present themselves. It is found,
for example, with a hydrogen flame that the luminosity diminishes as the
purity of the hydrogen is increased and as the air is freed from dust,
and J.S. Stas declared that under the most favourable conditions he was
only able, even in a dark room, to localize the flame by feeling for it,
an observation consistent with the fact that the line spectrum of the
flame lies wholly in the ultra-violet. On the other hand, there are many
examples of chemical combination between gases where the attendant
radiation is below the pitch of visibility, as in the case of ethylene
and chlorine. It will be obvious from these facts that a strict
definition of flame is hardly possible. The common distinction between
luminous and non-luminous flames is, of course, quite arbitrary, and
only corresponds to a rough estimate of the degree of luminosity.
The chemical energy necessary for the production of flame may be
liberated during combination or decomposition. A single substance like
gun-cotton, which is highly endothermic and gives gaseous products, will
produce a bright flame of decomposition if a single piece be heated in
an evacuated flask. Combination is the more common case, and this means
that we have two separate substances involved. If they be not mixed _en
masse_ before combination, the one which flows as a current into the
other is called conventionally the "combustible," but the simple
experiment of burning air in coal gas suffices to show the unreality of
this distinction between combustible and supporter of combustion, which,
in fact, is only one of the many partial views that are explained and
perhaps justified by the dominance of oxygen in terrestrial chemistry.
Although hydrocarbon flames are the commonest and most interesting, it
will be well to consider simpler flames first in order to discuss some
fundamental problems. In hydrocarbon flames the complexity of the
combustible, its susceptibility to change by heating, and the
possibilities of fractional oxidation, create special difficulties. In
the flame of hydrogen and oxygen or carbon monoxide and oxygen we have
simpler conditions, though here, too, things may be by no means so
simple as they seem from the equations 2H2 + O2 = 2H2O and 2CO + O2 =
2CO2. The influence of water vapour on both these actions is well known,
and the molecular transactions may in reality be complicated. We shall,
however, assume for the sake of clearness that in these cases we have a
simple reaction taking place throughout the mass of flame. There are
various ways in which a pair of gases may be burned, and these we shall
consider separately. Let us first suppose the two gases to have been
mixed _en masse_ and a light to be applied to the stationary mixture. If
the mixture be made within certain limiting proportions, which vary for
each case, a flame spreads from the point where the light is applied,
and the flame traverses the mixture. This flame may be very slow in its
progress or it may attain a velocity of the order of one or two thousand
metres per second. Until comparatively recent times great
misunderstanding prevailed on this subject. The slow rate of movement of
flame in short lengths of gaseous mixtures was taken to be the velocity
of explosion, but more recent researches by M.P.E. Berthelot, E.
Mallard and H.L. le Chatelier and H.B. Dixon have shown that a
distinction must be made between the slow _initial rate of inflammation_
of gaseous mixtures and the _rapid rate of detonation_, or rate of the
_explosive wave_, which in many cases is subsequently set up. We shall
here deal only with the slow movements of flame. The development of a
flame in such a gaseous mixture requires that a small portion of it
should be raised to a temperature called the _temperature of ignition_.
Here again considerable misunderstanding has prevailed. The temperature
of ignition has often been regarded as the temperature at which chemical
combination begins, whereas it is really the temperature at which
combination has reached a certain rate. The combination of hydrogen and
oxygen begins at temperatures far below that of ignition. It may indeed
be supposed that the combination occurs with extreme slowness even at
ordinary temperatures, and that as the temperature is raised the
velocity of the reaction increases in accordance with the general
expression according to which an increase of 10 deg.C. will
approximately double the rate. However that may be, it has been proved
experimentally by J.H. van't Hoff, Victor Meyer and others that the
combination of hydrogen and oxygen proceeds at perceptible rates far
below the temperature of ignition. The phenomenon appears to be greatly
influenced by the solid surfaces which are present; thus in a plain
glass vessel the combination only began to be perceptible at 448 deg.,
whilst in a silvered glass vessel it would be detected at 182 deg. C.
The same kind of thing is true for most oxidizable substances, including
ordinary combustibles. We must look upon the application of heat to a
combustible mixture as resulting in an increase of the rate of
combination locally. Let us suppose that we are dealing with a stratum
of the mixture in small contiguous sections. If we raise the temperature
of the first section _a_ deg. C., an increased rate of combination is
set up. The heat produced by this combination will be dissipated by
conduction and radiation, and we will suppose that it does not quite
suffice to raise the adjacent section of the mixture to _a_ deg.C. The
combination in that section, therefore, will not be as rapid as in the
first one, and so evidently the impulse to combination will go on
abating as we pass along the stratum. Suppose now we start again and
heat the first section of the mixture to a temperature _c_ deg.C., such
that the rate of combination is very rapid and the heat developed by
combination suffices to raise the adjacent section of the mixture to a
temperature higher than _c_ deg.C. The rate of combination will then be
greater than in the first section, and the impulse to combination will
be intensified in the same way from section to section along the stratum
until a maximum temperature is reached. It is obvious that there must be
a temperature of _b_ deg.C. between _a_ deg. and _c_ deg. which will
satisfy this condition, that the heat which results from the combination
stimulated in the first section just suffices to raise the temperature
of the second section to _b_ deg. This temperature _b_ deg. is the
temperature of ignition of the mixture; so soon as it is attained by a
portion of the mixture the combustion becomes self-sustaining and flame
spreads through the mixture. Ignition temperature may be defined briefly
as the temperature at which the initial loss of heat due to conduction,
&c., is equal to the heat evolved in the same time by the chemical
reaction (van't Hoff). From the above considerations we see that the
temperature of ignition will vary not only when the gases are varied,
but when the proportions of the same gases are varied, and also when the
pressure is varied. We can see also that outside certain limiting
proportions a mixture of gases will have no practicable ignition
temperature, that is to say, the cooling effect of the gas which is in
excess will carry off so much heat that no attainable initial heating
will suffice to set up the transmission of a constant temperature. Thus
in the case of hydrogen and air, mixtures containing less than 5 and
more than 72% of hydrogen are not inflammable. The theory of ignition
temperature enables us to understand why in an explosive mixture a very
small electric spark may not suffice to induce explosion. Combination
will indeed take place in the path of the spark, but the amount of it is
not sufficient to meet the loss of heat by conduction, &c. It must be
added that the theory of ignition temperatures given above does not
explain all the observed facts. F. Emich states that the inflammability
of gaseous mixtures is not necessarily greatest when the gases are mixed
in the proportions theoretically required for complete combination, and
the influence of foreign gases does not appear to follow any simple law.
The presence of a small quantity of a gas may exercise a profound
influence on the ignition temperature as in the case of the addition of
ethylene to hydrogen (Sir Edward Frankland), and again when a mixture of
methane and air is raised to its ignition temperature a sensible
interval (about 10 seconds) elapses before inflammation occurs.
The rate at which a flame will traverse a mixture of two gases which has
been ignited depends on the proportions in which the gases are mixed.
Fig. 1 (Bunte) represents this relationship for several common gases.
[Illustration: FIG. 1.--Rates of inflammation of combustible gases with
air.]
If a ready-made gaseous mixture is to be used for the production of a
steady flame, it may be forced through a tube and ignited at the end; it
is obvious that the velocity of efflux must be greater than the initial
rate of inflammation of the mixture, for otherwise the mixture would
fire back down the tube. If the velocity of efflux be considerably
greater than the rate of inflammation, the flame will be separated from
the end of the tube, and only appear as a flickering crown where the
velocity and inflammability of the issuing gas have been diminished by
admixture with air. With much increased velocity of efflux the flame
will be blown out. J.B.A. Dumas used to show the experiment of blowing
out a candle with electrolytic gas. A steady flame formed by burning a
ready-made gaseous mixture at the end of a tube of circular section has
the form shown in fig. 2. The small internal cone marks the lower
limiting surface of the flame; it is the locus of all points where the
velocity of efflux is just equal to the velocity of inflammation, and
its conical form is explained by the fact that the rate of efflux of gas
is greatest in the vertical axis of the tube where the flow is not
retarded by friction with the walls, as well as by the further fact that
the gas issuing from such an orifice spreads outwards, the inflammation
proceeding directly against it. The flame, it will be seen, is of
considerable thickness. If the gaseous mixture be hydrogen and oxygen,
or carbon monoxide and oxygen, it will have no obvious features of
structure beyond those shown in the figure; that is to say, the shaded
region of burning gas has the appearance of homogeneity and uniform
colour which might be expected to accompany a uniform chemical
condition. Some admixture of the external air will, of course, take
place, especially in the upper parts of the flame, and detectable
quantities of oxides of nitrogen may be found in the products of
combustion, but this is an inconsiderable feature. The flame just
described is essentially that of a blowpipe.
[Illustration: FIG. 2.]
A second way of producing a flame is the more common one of allowing one
gas to stream into the other. Using the same gases as before, hydrogen
or carbon monoxide with oxygen, we find again that the flame is conical
in form and uniform in colour, but in this case, if the velocity of
efflux be not immoderate, the burning gas only extends over a
comparatively thin shell, limited on the inside by the pure combustible
and on the outside by a mixture of the products of combustion with
oxygen. The combustible gas has to make its own inflammable mixture with
the circumambient oxygen, and we may suppose the column of gas to be
burned through as it ascends. The core of unburned gas thus becomes
thinner as it ascends and the flame tapers to a point. The external
surface of a flame of this kind will for the same consumption of gas be
larger than that of a flame where the ready-made mixture of gases is
used. If a jet of one gas be sent with a sufficient velocity into
another, turbulent admixture takes place and an unsteady sheet of flame
of uniform colour is obtained.
A third way of forming a flame is to allow the whole of one gas, mixed
with a less quantity of the second than is sufficient for complete
combustion, to issue into an atmosphere of the second. This is the case
with what are generally known as atmospheric burners, of which the
Bunsen burner is the prototype. The development of a flame of this kind
can be well studied in the case of carbon monoxide and air. The carbon
monoxide is fed into a Bunsen burner with closed air-valve, the
burner-tube being prolonged by affixing a glass tube to it by means of a
cork. The flame consists of a single conical blue sheet. If now the
air-valve be opened very slightly, an internal cone of the same blue
colour makes its appearance. The air which has entered through the
air-valve ("primary" air) has become mixed with the carbon monoxide and
so oxidizes its quota in an internal cone, the rest of the carbon
monoxide (diluted now, of course, with carbon dioxide and nitrogen)
wandering into the external atmosphere to burn (with "secondary" air) in
a second cone. The existence of the internal cone and the subsequent
thermal effect lead to slight convexity of surface in the outer cone. If
the quantity of primary air be increased more internal combustion can
take place. This, however, does not lead to an enlargement of the inner
cone, for the increase of air increases the rate of inflammation of the
mixture, and the inner cone (which only maintains its stability because
the rate of efflux of the mixture is greater than the velocity of
inflammation) contracts, and will, as the proportion of primary air is
increased, soon evince a tendency to enter the burner-tube. At this
stage an interesting phenomenon is to be noticed. When we have reached
the point of aeration where the velocity of inflammation of the mixture
just surpasses the velocity of efflux, the inner cone enters the
burner-tube as a disk and descends, but this downward motion checks the
suction flow of air through the valve at the base of the burner, whilst
it does not appreciably check the pressure flow of the carbon monoxide
through the gas nozzle. The result is that a stratum of gas-mixture poor
in air, and therefore of low rate of inflammation, is formed, and when
the descending disk of flame meets it, the descent is arrested and the
disk returns to the top of the tube, reproducing the inner cone. The
full air suction is now restored and the course of events is repeated.
This oscillatory action can be maintained almost indefinitely long if
the pressure and other conditions be maintained constant. With still
more primary air the inner cone of flame simply fires back to the burner
nozzle, or, in the last stage, we may have enough air entering to
produce a flame of the blast blowpipe type, namely, one where the carbon
monoxide mixed with an _excess_ of primary air burns with a single cone
in a steady flame.
By means of a simple contrivance devised by A. Smithells a two-coned
flame of the kind described may be resolved into its components. The
apparatus is like a half-extended telescope made of two glass tubes, and
it is evident that the velocity of a mixture of gases flowing through it
must be greater in the narrow tube than in the wider one. If the end of
the narrower tube be fixed to a Bunsen burner and the flame be formed at
the end of the wider one, then when the air-supply is increased to a
certain point the inner cone will descend into the wide tube and attach
itself to the upper end of the narrower one. This occurs when the
velocity of inflammation is just greater than the upward velocity of the
gaseous stream in the wide tube and less than the upward velocity in the
narrow tube. If the outer tube be now drawn down, a two-coned flame
burns at the end of the inner tube; if the outer tube be slid up again,
it detaches the outer cone and carries it upward. This apparatus has
been of use in investigating the progress of combustion in various
flames.
_Temperature of Flames._--The term "flame-temperature" is used very
vaguely and has no clear meaning unless qualified by some description.
It is least ambiguous when used in reference to flames where the
combining gases are mixed in theoretical proportions before issuing from
the burner. The flame in such a case has considerable thickness and
uniformity, and, though the temperature is not constant throughout,
flames of this type given by different combustibles admit of comparison.
In other flames where the shells of combustion are thin and envelop
large regions of unburned or partly-burned gas, it is not clear how
temperature should be specified. An ordinary gas-flame will not, from
the point of view of the practical arts, give a sufficient temperature
for melting platinum, yet a very thin platinum wire may be melted at the
edge of the lower part of such a flame. The maximum temperature of the
flame is therefore not in any serious sense an available temperature. It
will suffice to point out here that in order to burn a gas so that it
may have the highest available temperature, we must burn it with the
smallest external flame-surface obtainable. This is done when the
combining gases are completely mixed before issuing from the burner.
Where this is impracticable we may employ a burner of the Bunsen type,
and arrange matters so that a large amount of primary air is supplied.
It is in this direction that modern improvements have been made with a
view to obtaining hot flames for heating the Welsbach mantle. The Kern
burner, for example, employs the principle of the Venturi tube. Where
much primary air is drawn in it is usual to provide for it being well
mixed with the gas, otherwise an unsteady flame may be produced with a
great tendency to light back. The burner head is therefore usually
provided with a mixing chamber and the mixture issues through a slit or
a mesh. A great many modified Bunsen burners have been produced, the aim
in all of them being to produce a flame which shall combine steadiness
with the smallest attainable external surface.
To estimate the temperature of flames several methods have been
employed. The method of calculation, based on the supposition that the
whole heat of combustion is localized in the product (or products) of
combustion and heats it to a temperature depending on its specific heat,
cannot be applied in a simple way. Apart from the assumption (which
there is reason to suppose incorrect) that none of the chemical energy
assumes the radiant form directly, we have to regard the possible change
of specific heat at high temperatures, the likelihood of dissociation
and the time of reaction. Any practical consideration of temperature
must have regard to a large assemblage of molecules and not to a single
one, and therefore any influence which means delay in combination will
result in reduction of temperature by radiation and conduction. It can
hardly be maintained that in the present state of knowledge we have the
requisite data for the calculation of flame temperature, though good
approximations may be made. Many attempts have been made to determine
flame temperatures by means of thermo-electric couples and by radiation
pyrometers. The couple most employed is that known as H.L. le
Chatelier's, consisting of two wires, one of platinum and the other an
alloy of 90% platinum and 10% of rhodium. When all possible precautions
are taken it is possible by means of such thermo-couples to measure
local flame temperatures with a considerable degree of accuracy.
Subjoined are some results obtained at different times and by different
observers with regard to the maximum temperatures of flames:--
Coal gas in Bunsen burner (Waggener, 1896) 1770 deg. C.
" " " " (Berkenbusch, 1899) 1830 deg.
" " " " (White & Traver, 1902) 1780 deg.
" " " " (Fery, 1905) 1871 deg.