Improvements in the Manufacture of Incandesoing Media for Lighting Purposes.
Year: 1897

page_text: Date of Application, 5th June, 1897
Complete Specification Left, 5th Mar., 1898-Accepted, 16th Apr.,
1898
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Incandesoing Media for
Lighting Purposes.
I, RUDOLF LANGILANS, of 12u, Elisabeth Strasse, Berlin, in the German Empire,
Electrician, do hereby declare the nature of this invention to be as follows:-
The phenomena exhibited by bodies which become incandescent in the heat
zone of non-luminous gas dames are simple or complex according to the com-
position of the body or bodies employed. Pure oxide of thorium (Th 0,) when
incandescent emits very little light, and is fairly constant in the flame. Puro
oxide of zirconium (Zr 0) brought to incandescence affords a slightly greater light
emission than pure thorin; but after a short time it sinters, or burns dead, in
the Bunsen flame. Ordinary commercial thoria and zirconia (which contain
impurities or traces of the rare earths of the cerite group) respectively give when
in the incandescent state five times and two and a half times more light than pure
thoria or pure zirconia. An addition of 1 per cent. of ceria to pure lhoria has the
effect of very largely increasing the light emission.
The oxides of the earth-alkali group of metals, calcium, barium and strontium,
in an incandescent state have a relatively high light emission, exceeding in this
respect any of the earth and rare earth metals except yttrium and lanthanum.
The two latter belong to the cerite group and only form one combination with
oxygen.
Cerium oxide as an incandescent is weak in light emissiveness; but owing to
the quality it has of varying its combinations with oxygen in the heat zone of a
non-luminous gas flame, it is of great value in forming, with the oxides of thorium
and zirconium, incandescing bodies for use in gas-lighting.
Since it is not possible to obtain in skeleton form a structure composed of the
oxide of any one earth, rare earth or earth-alkali metal, which will give the
maximum of light emission in a non-luminous gas flame, it is necessary to com-
bino two or more oxides, and one of the oxides must be capable of varying in the
gas flame its oxygen compounds. Cerium forms with oxygen two compounds,
cerium sesquioxide (Ce, Og) and cerium dioxide (Ce Og). In the heat zone of a
non-luminous gas flame cerin fluctuates between these two forms of oxides by con-
tinuously consuming and taking up oxygen. That is to say, it is reduced in the
Bunsen flame from a higher to a lower oxide, and by re-oxidation reassumes the
higher form. Hence ceria, as a fluctuating oxide compound, plays a vitally
important part in the composition of incandescing bodies.
In the prosecution of my researches in connection with the incandescing qualities
of metallic substances, I have discovered that vanadium-pentoxide performs pro-
cisely the same function as that performed by ceria, in consequence of the pent-
oxide being reduced to a trioxide in the heat zone of a Bunsen burner, and
immediately reassuming its higher oxide form by the absorption of oxygen from
the atmosphere. In the Specification filed in pursuance of my application for

page_text: Letters Patent No. 14,845 of 1896, and in the Specification which accompanied
my application for Letters Patent No. 501 of 1897, I have fully described and
set forth the manner of employing vanadine pentoxide with zirconium and thorium
in the production of vanadiniferous zirconia and vanadiniferous thoria for use
in the manufacture of incandescing bodies for employment in gas-lighting.
Subsequent researches have enabled me to determine with more accuracy the
molecular properties essential to an incandescent body having the highest light
emission, coupled with the greatest stability of form and light permanency.
The structure of the incandescent body must have great porosity in order to
enable the atmosphere to have access to the greatest number of molecules. A
difficulty is here encountered owing to the fact that such a structure admits pro-
portionate quantities of gas to the pores of the body, a condensation thereof taking
place in the pores upon and around the molecules of the oxides with an energy
proportionate to the molecular weight of the oxides. This condensation not only
prevents perfect combustion of the gases, the enveloped molecules consequently
mot attaining the high temperature essential to perfect incandescence, but the
access of oxygen from the atmosphere, required by an oxide of high molecular
weight, like thoria, is shut out by the screen of condensed gases. Hence a body
of pure thoria which, on account of its high molecular weight, is so extremely
favourable to the attraction of atmospheric oxygen, proves very weak in luminous
capacity. The "fluctuating oxide" as I term the oxygen-compound added to
the earth oxide-gives off oxygen from within to the condensed gases and induces
very energetic combustion with the generation of a proportionately high tempera-
ture; and this temperature is maintained by the subsequent absorption of oxygen
in the re-oxidation of the reduced oxide.
The addition of ceria, or of vanadium-pentoxide, beyond a certain propor-
tionate percentage, decreases the light-emission, and the explanation of the
necessity for the relatively small proportions of "fluctuating oxide," deducible
from the foregoing, is as follows;-
:―
The molecular combination of a substance of high molecular weight with one
of low molecular weight produces proportionately numerous molecules, and con-
sequently the less will be the distance of the molecules of light weight from each
other; therefore, the greater the number of the molecules of the "fluctuating
oxide" in the structure of the incandescent body, the greater will be the oppor-
tunities for condensation of gases and the less perfect the combustion consequent
upon the inadequate supply of oxygen.
"
Another phenomenon exhibited by all incandescent bodies is the marked decrease
in light-emission after a certain period of incandescence. This behaviour is, how-
ever, not attributable to unfavourable changes in the structure, such as "sintering
or "dead-burning" of the earthy oxide, but is due to the "fluctuating oxide"
becoming more and more indifferent by reason of the formation of an intermediate
compound, or complex oxide, which is incapable of giving off and reabsorbing
oxygen under the action of alternate reducing and oxidizing influences.
I have observed that the commencement of the decrease of light-emission coin-
cides with the formation of brownish coloured point-like spots in the zone where
the heat is greatest, and that these spots grow in number and size until finally
the body assumes a bronze-like appearance in the said zone, with the result that
its value as a source of light is largely reduced.
Taking into consideration the degrees of oxidation of vanadium, that is, the
vibration from pentoxide to trioxide and vice versa, and that compounds might
be formed with the oxides of the alkali and earth-alkali metals in which the
fluctuations continue without causing intermediate or complex compounds, I was
induced to experiment in order to determine whether the formation of indifferent
intermediate or complex oxides might be prevented; and with this object I intro-
duced an oxide of an alkali metal capable of molecular combination with the
oxygen-vanadium compound and of acting as an oxygen conveyer without becoming
indifferent. The addition of a higher percentage of vanadium-pentoxide accelerated

page_text: the appearance of the bronze-like offect, and the introduction of an alkali-oxido
delayed it for a brief period. I found that the alkali-oxide was completely elimina-
ted from the body by vaporization. Being satisfied that the alkali-oxides would
not secure permanent light effect, I did not pursue the experiment to determine
the effect an alkali-oxide would have on the coherence of the mass and the per-
manency of volume, or shape, of bodies made in the form of mantles. It was
however evident, that an alkali-oxide did exert some influence in retarding the
bronze-like apote, and I accordingly continued my experiments by replacing the
alkali-oxides with oxides of the earth-alkali metals, as these are said not to be
subject to vaporization.
First, I introduced into a solution of zirconium nitrate a small proportion of
calcium hydroxide calculated upon the percentage of vanadium-pentoxide, or
vanadyle salt, employed. From this fluid, I made bodies which remained free
from the bronze-like colour and which maintained a bright incandescence. They,
however, shrank in the middle part to such an extent that the body was soon out
of the heat zone. The coherence was good and the elasticity marked. The
shrinking took place with either zirconin or thoria irrespectively of the earth-
alkali used.
The fact that the addition of earth-alkali hydroxide to the dissolved zirconium
nitrate, or to the thorium nitrate, caused metazirconium hydrate, or metathorium
hydrate, to separate out, which readily redissolves, forming in the fluid a basic
zirconia or basic thoria salt together with nitrate of calcium led me to the con-
clusion that in calcining, to drive off the acid, the zirconium or thorium hydrate
present in the molecule of the basic zirconia or thoria salt, caused a "binding"
to take place between the resulting oxide of the earth-alkali metal and the
zirconium or thorium dioxide; and that therefore the coherenco was due to the
binding." Also, that the shrinking, or inconstancy of volume in heat, resulted
from the use of an insufficient percentage of the earth-alkali in the complex com-
pound formed under the action of heat.
65
This assumption was confirmed by the entirely different behaviour of mantles
impregnated with a fluid prepared by mixing a vanadiniferous solution of
zirconium nitrate with calcium nitrate, so as to prevent the formation of metazir-
conium nitrate. There was under these conditions no zirconium hydrate present
for "binding" the calcium oxide in the calcining stage, there being only zirconium
dioxide in contact with the calcium oxide; and, as is well known, the dioxide
will not quite with an earth-alkali to form a zirconate. The coherence is so loose
that the mere mechanical mixture of the two oxides falls down in a sand-like
powder.
By employing successively increased percentages of the oxides of the earth-alkali
motals, I observed a successively increased reduction of shrinking, until I finally
succeeded in obtaining permanent light-emission from vanadiniferous zirconia or
vanadiniferous thoria bodies without injuring either their coherence or their
regularity of volume or shape, in the heat.
The percentage of earth-alkali oxide must be up to the limit of the "
binding"
between that oxide and the zirconia, or thoria-i.e., up to the formation of a
neutral zirconate, or thorate, R. (Zr. Th. O), RI (Ca. Sr. Ba.) ()--but must not
surpass that limit, because at that point the volume or shape of the body com-
mences to alter in the reverse direction--i.e., is caused to swell; and this effect
increases as the excess of the earth-alkali is augmented.
Calcium oxide is most favourable to the obtaining of permanency of volume
and shape, whilst strontium oxide and barium oxide, especially the fatter, are in
a certain degree uustable in that respect. On the other hand, the latter exert a
beneficial effect on the lighting power of the body. I am inclined to attribute
this behaviour of the latter oxides to their property of forming peroxides when
exposed to the air at a high temperature, whereby they are caused to act as an
additional source of oxygen. In order to unite both advantages, I prefer to use
the calcium oxide in combination with the strontium oxide or with barium oxide.

page_text: I have, however, found that a slight addition of an alkali, preferably nitrate
of alkali, has the effect of encouraging the "binding" which takes place between
the earth-alkali oxide and the oxygen-vanadium compound in the calcining step.
In manufacturing, I proceed as follows:-
I prepare an aqueous vanadiniferous solution of zirconium nitrate or thorium
nitrate, or zirconium and thorium nitrates, and in this solution dissolve the
required percentage of the earth-alkali in the form of hydroxide, the latter being
added in small portions while the liquid is stirred, each such addition causing
the separation of metazirconium hydrate, or thorium hydrate, which readily
redissolves. Instead of the hydroxides of the earth-alkali metals, the carbonates
or formiates of the same may be employed. In case the body is to be mauu-
factured by impregnating a fabric with the fluid, it should have such a concen-
tration that the weight of the (dry) salts represents 30 per cent.
Or I may mix the vanadiniferous solution of zirconium or thorium nitrate with
an aqueous solution containing the earth-alkali in the form of nitrate, and effect
the formation of metazirconium hydrate, or metathorium hydrate, by the addition
of ammonia, uniline or organic bases. Instead of these agents, the carbonates and
formiates of zirconium, or of thorium, may be used, but these are less advantageous.
It is not convenient to employ freshly and separately prepared metazirconium
hydrate, or metathorium hydrate, because of the large proportion of water
mechanically combined therewith since concentration will have to be effected at
a temperature not exceeding 40° Centigrade.
According to another method, I prepare an aqueous solution of vanadium-pent-
oxide, or of a vanadyle salt, and in this 1 dissolve the earth-alkali nitrate. To
this solution, add an aqueous solution of an oxychloride of zirconium, or a
corresponding thorium compound. With this method, it is the elimination of
chlorine from the molecule of the oxychloride in the calcining step which enables
the formation of the earth-alkali zirconate to take place. The fluid in this case
is also prepared with the concentration above mentioned, if it be intended for
impregnating.
If the reverse course be pursued and the fluid prepared with zirconium or
thorium nitrate and oxychlorides or chlorides of the earth-alkali metals, the
result will be unsatisfactory; because the greater part of the oxychlorides or
chlorides will he eliminated from the body by evaporation before the binding
temperature is reached.
The oxychloride method is advantageous in that the zirconium oxychlorides,
of which I prefer the composition Zг О. Cl, can be obtained entirely free from
iron.
I have also found that in the manufacture of vanadiniferous zirconia and thoria
incandescing bodies, the vanadium-pentoxide or vanadyle salts, with or without
the employment of earth-alkali, can be replaced by other oxygen-vanadium com-
pounds; such as divanadyle salts, vanadiuic acids, vanadates and hypovanadates,
and that these compounds constitute a very valuable means for shading the light
and furthering the conveyance of oxygen by employing those of them in which tho
other component has the property of causing a particular colour of light, or of
forming fluctuating oxides. The same is true of the complex acids-phosphor-
vanadium acid, niobvanadium acid, tantal-vaundium acid, arsenic-vanadium acid,
bismuth-vanadium acid, chrom-vanadium acid and the like, and their salts. If
these compounds contain an alkali, the above mentioned addition of alkali nitrate
may be dispensed with.

page_text: Improvements in the Manufacture of Incandescing Media for
Lighting Purposes.
I, RUDOLF LANGHLANS, of 12B, Elisabeth Strasse, Berlin, in the German Empire,
Electrician, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement:-
:-
The phenomena exhibited by bodies which become incandescent in the heat
zone of non-luminous gas flames are simple or complex according to the com-
position of the body or bodies employed. Pure oxide of thorium (Th. O₂) when
incandescent emits very little light, and is fairly constant in the flame. Pure
oxide of zirconium (Zr Og) brought to incandescence affords a slightly greater light
emission than pure thoria; but after a short time it sinters, or burns dead, in
the Bunsen fame. Ordinary commercial thoria and zirconia (which contain
impuritios or traces of the rare earths of the cerite group) respectively give when
in the incandescent state five times and two-and-a-half times more light than pure
thoria or pure zirconia. An addition of 1 per cent. of ceria to pure thoria has the
effect of very largely increasing the light emission.
The oxides of the earth-alkali group of metals, calcium, barium and strontium,
in an incandescent state have a relatively high light emission, exceeding in this
respect any of the earth metals and rare earth metals except yttrium and lanthanum.
The two latter belong to the cerite group and only form one combination with
oxygen.
Cerium oxide as an incandescent is weak in light emissiveness; but owing to
the quality it has of varying its combinations with oxygen in the heat zone of a
non-luminous gas flame, it is of great value in forming, with the oxides of thorium
and zirconium, incandescing bodies for use in gas-lighting.
Since it is not possible to obtain in skeleton form a structure composed of the
oxide of any one earth, rare earth or earth-alkali metal, which will give the
maximum of light emission in a non-luminous gas flame, it is necessary to com-
bine two or more oxides, and one of the oxides must be capable of varying in the
gas flame its oxygen compounds. Cerium forms with oxygen two compounds,
cerium sesquioxide (Ce, O3) and cerium dioxide (Ce, O₂). In the heat zone of a
mon-luminous gas flame ceria fluctuates between these two forms of oxides by cou-
tinuously consuming and taking up oxygen. That is to say, it is reduced in the
Bunsen flame from a higher to a lower oxide, and by re-oxidation reassumes the
higher form. Hence ceria, as a fluctuating oxide compound, plays a vitally
important part in the composition of incandescing bodies.
In the prosecution of my researches in connection with the incandescing qualities
of metallic substauces, I have discovered that vanadium-pentoxide performs pre-
cisely the same function as that performed by ceria, in consequence of the pent-
oxide being reduced to a trioxide in the zone of a Bunsen burner, and
immediately reassuming its higher oxide form by the absorption of oxygen from
the atmosphere. In the Specification filed in pursuance of my application for
Letters Patent, No. 14,845 of 1896, and in the Specification filed in pursuance of
my application for Letters l'atont, No. 501 of 1897, 1 have fully described and
set forth the manner of employing vanadium-pentoxide with zirconium; and
thorium in the production of vanadiniferous zirconia and vanadiniferous thoria
for use in the manufacture of incandescing bodies for employment in gas-lighting.

page_text: Subsequent researches have enabled me to determine with more accuracy the
molecular properties essential to an incandescent body having the highest light
emission, coupled with the greatest stability of form and light permanency.
The structure of the incandescent body must have great porosity in order to
enable the atmosphere to have access to the greatest number of molecules. A
difficulty is here encountered owing to the fact that such a structure adinits pro-
portionate quantities of gas to the pores of the body, a condensation thereof taking
place in the pores upon and around the molecules of the oxide with an energy
proportionate to the molecular weight of the oxides. This condensation not only
prevents perfect combustion of the gases, the enveloped molecules consequently
not attaining the high temperature essential to perfect incandescence, but the
access of oxygen from the atmosphere, required by an acid of high molecular
weight, like thoria, is shut out by the screen of condensed guses. Hence a body
of pure thoria, which, on account of its high molecular weight, is so extremely
favorable to the attraction of atmospheric oxygen, proves very weak in luminous
capacity. The " Auctuating oxide -as I term the oxygen-compound added to
the earth oxide-gives off oxygen from within to the condensed gases and induces
very energetic combustion with the generation of a proportionately high tempera-
ture; and this temperature is maintained by the subsequent absorption of oxygen
in the re-oxidation of the reduced oxide.
The addition of cerin, or of vanadium-pentoxide, beyond a certain propor-
tionate percentage, decreuses the light-emission, and the explanation of the
necessity for the relatively small proportions of "fluctuating oxide,” deducible
from the foregoing, is as follows:-
The molecular combination of a substance of high molecular weight with one
of low molecular weight produces proportionately numerous molecules, and cou-
sequently the less will be the distance of the molecules of light weight from each
other; therefore, the greater the number of the molecules of the ". fluctuating
oxide" in the structure of the incandescent body, the greater will be the oppor-
tunities for condensation of gases and tho, less perfect the combustion consequent
upon the inadequate supply of oxygen.
"
"
Another phenomenon exhibited by all incandescent bodies is the marked decrease
in light-emissiou after a certain period of incandescence. This behaviour is, how-
ever, not attributable to unfavourable changes in the structure, such as "sintering
or "dead-burning" of the earthy oxide, but is due to the "fluctuating oxide'
becoming more and more indifferent by reason of the formation of an intermediate
compound, or complex oxide, which is incapable of giving off and reabsorbing
oxygen under the action of alternate reducing and oxidizing influences.
I have observed that the commencement of the decrease of light-emission coin-
cides with the formation of brownish coloured point-like spots in the zone where
the heat is greatest, and that these spots grow in number and size until finally
the body assumes a bronze-like appearance in the said zone, with the result that
its value as a source of light is largely reduced.
Taking into consideration the degrees of oxidation of vanadium, that is, the
vibration from pentoxide to trioxide and vice versa, and that compounds might
be formed with the oxides of the alkali and earth-alkali metals in which the
fluctuations continue without causing intermediate or complex compounds, I was
induced to experiment in order to determine whether the formation of indifferent
.intermediate or complex oxides might be prevented; aud with this object 1 intro-
duced an oxide of an alkali metal, capable of molecular combination with the
oxygen-vanadium compound and of acting as an oxygen conveyor without becoming
indifferent. The addition of a higher percentage of vanadium-pentoxide accelerated
the appearance of the bronze-like effect, and the introduction of an alkali-oxide
delayed it for a brief period. I found that the alkali-oxide was completely elimina-
ted from the body by vapourization. Being satisfied that the alkali-oxides would
not secure permanent light effect, I did not pursue the experiment to determine

page_text: the effect an alkali-oxide would have on the coherence of the mass and the per-
manency of volume, or shape, of bodies made in the form of mantles. It was
however evident that an alkali-oxide did exert some influence in retarding the
bronze-like spots, and I accordingly continued my experiments by replacing the
alkali-oxides with oxides of the carth-alkali metals, as these are said not to be
subject to vapourization.
First, I introduced into a solution of zirconium nitrate a small proportion of
calcium hydroxide calculated upon the percentage of vanadium-pentoxide, or
vanadyle salt, employed. From this fluid I made bodies which remained free
from the bronze-like colour and which maintained a bright incandescence. They,
however, shrank in the middle part to such an extent that the body was soon out
of the heat zone. The coherence was good and the elasticity marked. The
shrinking took place with either zirconia or thoria irrespectively of the earth-
alkali used.
"
The fact that the addition of earth-alkali hydroxide to the dissolved zirconium
nitrate, or to the thorium nitrate, caused metazirconium, or metathorium
hydrate, to separate out, which readily redissolves, forming in the fluid a basic
zirconia or basic thoria salt together with nitrate of calcium led me to the con-
clusion that in calcining, to drive off the acid, the zirconium or thorium hydrate
present in the molecule of the basic zirconia or thoria salt, caused a "binding'
to take place between the resulting oxide of the earth-alkali metal and the
zirconium or thorium dioxide; and that therefore the coherence was due to the
'binding." Also that the shrinking, or inconstancy of volume in heat, resulted
from the use of an insufficient percentage of the earth-alkali in the complex com-
pound formed under the action of heat.
This assumption was confirmed by the entirely different behaviour of mantles
impregnated with a fluid prepared by mixing a vanadiniferous solution of
zirconium nitrate with calcium nitrate, so as to prevent the formation of metazir-
conium nitrate. There was under these conditions no zirconium hydrate present
for "binding" the calcium oxide in the calcining stage, there being only zirconium
dioxide in contact with the calcium oxide, and, as is well known, the dioxide
will not unite with an earth-alkali to form a zirconate. The coherence is so loose
that the mere mechanical mixture of the two oxides falls down in a sand-like
powder.
By employing successively increased percentages of the oxides of the earth-alkali
metals, I observed a successively increased reduction of shrinking, until I finally
succeeded in obtaining permanent light-emission from vanadiniferous zirconia or
vanadiniferous thoria bodies, without injuring either their coherouce or their
regularity of volume or shape in the heat.
The percentage of carth-alkali oxide must be up to the limit of the "binding"
between that oxide and the zirconia, or thoria-i.e., up to the formation of a
neutral zirconate, or thorate, R (Zr. Th. O₂), R1 (Ca. Sr. Ba.) 0-but must not
surpass that limit, because at that point the volume or shape of the body com-
mences to alter in the reverse direction-i.e., is caused to swell; and this effect
increases as the excess of the earth-alkali is augmented.
Calcium oxide is most favourable to the obtaining of permanency of volume
and shape, whilst strontium oxide and barium oxide, especially the latter, are in
a certain degree unstable in that respect. On the other hand, the latter exert a
Leneficial effect on the lighting power of the body. I am inclined to attribute
this behaviour of the latter oxides to their property of forming peroxides when
exposed to the air at a high temperature, whereby they are caused to act as an
additional source of oxygen. In order to unite both advantages, I prefer to use
the calcium oxide in combination with the strontium oxide or with barium oxide.
I have, however, found that a slight addition of an alkali, preferably nitrate
of alkali, has the effect of encouraging the "binding" which takes place between
the earth-alkali oxide and the oxygen-vanadium compound in the calcining step.

page_text: The following are examples of good preparations:-
Zirconium Oxychloride (Zr.O,C₁₁)
Calcium Nitrate (free from water)
I.
-
Vanadium-pentoxide (V₂O)
Nitrate of Alkali
62
per cont.
36
per cent.
0.12 per ceut.
1.88 per cent.
Zirconium Nitrate
Strontium hydroxide
Nitrate of Alkali
Vanadium-pentoxide (V,O,)
II.
68.2 per cent.
30
per cent.
In manufacturing, I proceed as follows:-
0.12 per cent.
1.68 per cent.
I prepare an aqueous vanadiniferous solution of zirconium nitrate or thorium
nitrate, or zirconium and thorium nitrates, and in this solution dissolve the
required percentage of the earth-alkali in the form of hydroxide, the latter being
added in small portions while the liquid is stirred, each such addition causing
the separation of metazirconium hydrate or thorium hydrate, which readily
redissolves. Instead of the hydroxides of the earth-alkali metals, the carbonates
or formiates of the same may be employed. In case the body is to be mauu-
factured by impregnating a fabric with the fluid, it should have such a concen-
tration that the weight of the (dry) salts represents 30 per cent.
Or I may mix the vanadiniferous solution of zirconium or thorium nitrate with
an aqueous solution containing the earth-alkali in the form of nitrate, and effect
the formation of metazirconium hydrate, or metathorium hydrate, by the addition
of ammonia, aniline or organic bases. Instead of these agents, the carbonates and
formiates of zirconium, or of thorium, may be used, but these are less advantageous.
It is not convenient to employ freshly and separately prepared metazirconium
hydrate, or metathorium hydrate, because of the large proportion of water
mechanically combined therewith since concentration will have to be effected at
a temperature not exceeding 40° Centigrade.
According to another method, I prepare an aqueous solution of vanadium-pent-
oxide, or of a vanadyle salt, and in this I dissolve the earth-alkali nitrate. To
this solution, I add an aqueous solution of an oxychloride of zirconium, or a
corresponding thorium compound. With this method, it is the elimination of
chlorine from the molecule of the oxychloride in the calcining step which enables
the formation of the earth-alkali zirconate to take place. The fluid in this case
is also prepared with the concentration above mentioned, if it be intended for
impregnating.
If the reverse course be pursued, and the fluid prepared with zirconium or
thorium nitrate and oxychlorides or chlorides of the earth-alkali metals, the
result will be unsatisfactory; because the greater part of the oxychlorides or
chlorides will be eliminated from the body by evaporation before the binding
temperature is reached.
The oxychloride method is advantageous in that zirconium oxychlorides,
of which I prefer the composition Zr, O, Cl, can be obtained entirely free from
iron.
I have also found that in the manufacture of vanadiniferous zirconia and thoria
incandescing bodies, the vanadium-pentoxide or vanadyle salts, with or without
the employment of earth-alkali, can be replaced by other oxygen-vanalium com-
pounds; such as, divanadyle salts, vanadinic acids, vanadates and hypovanadates,
and that these compounds constitute a very valuable means for shading the light
and furthering the conveyance of oxygen by employing those of them in which the
other component has the property of causing a particular colour of light, or of
forming fluctuating oxides. The same is true of the complex acids-phosphor-
vanadium acid, niobvanadium acid, tantal-vanadium acid, arsenic-vanadiuin acid,

page_text: bismuth-vanadium acid, chrom-vanadium acid and the like, and their salts. If
these compounds contain an alkali, the above mentioned addition of alkali nitrete
may be dispensed with.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I claim:-
1. The improved manufacture of incandescing bodies from vanadiniferous
zirconia, or vanadiniferous thoria, wherein the vanadium-oxygen compound, intro-
duced as V, O, is bound to the earth-alkali oxide or oxides, and the latter to the
earth oxide or oxides, substantially as herein described, whereby the light emission
is prolonged and shrinking in the heat prevented.
2. In the preparation of an impregnating solution for use in the manufacture
of incandescing bodies of the kind herein referred to, adding to an aqueous solution
zirconium nitrate or thorium nitrate, calcium hydroxide or other suitable earth-
alkali oxide, hydrate, carbonate or formiate, substantially as herein described.
of
3. In the preparation of an impregnating solution for use in the manufacture
of incandesciug bodies of the kind above referred to, adding to the mixed vanadin-
iferous solution of zirconium nitrate or thorium nitrate and earth-alkali nitrate,
ammonia, aniline or an organic base, or carbonate or formiate of zirconium or of
thorium, substantially as herein described.
4. In the preparation of an impregnating solution for use in the manufacture
of incandescing bodies of the kind herein referred to, adding a vanadiniferous
solution of an earth alkali salt to an aqueous solution of zirconium oxychloride or
thorium oxychloride, substantially as herein described.
5. In the preparation of an impregnating solution for use in the manufacture
of incandescing bodies of the kind herein referred to, the employment of calcium
oxide and strontium oxide together, or of calcium oxide and barium oxide together,
substantially as and for the purpose set forth.
6. In the manufacture of incandescing bodies from vanadiniferous zirconia or
vanadiniferous thoria, the employment of an alkali salt, substantially as hercin
described, whereby "binding" between the earth-alkali oxide or oxides, and the
oxygen-vanadium compound or compounds during calcination is promoted.
7. In the manufacture of incandesciug bodies from vanadiniferous zirconia, or
vauadiniferous thoria, with or without carth-alkali oxides, the employment, in
place of vanadium-pentoxide or vanadyle salts, of other vanadium-oxygen com-
pounds capable of acting as oxygen conveyers, including the so-called complex
vanadinic acids and the salts of the same, substantially as herein described.
8. In the manufacture of incandescing bodies from vanndiniferous zirconia or
vanadiniferous thoria, the employment of an impregnating solution containing
zirconia oxychloride, calcium nitrate (free from water), vanadium-pentoxide and
nitrate of alkali, substantially in the proportions herein prescribed.
9. In the manufacture of incandescing bodies from vanadiniferous zirconia or
vanadiniferous thorin, the employment of an impregnating solution containing
zirconia nitrate, strontium hydroxide, vanadium-pentoxide and nitrato of alkali,
substantially in the proportions herein prescribed.
DL: 6th Jan of amb 1909