IMPROVED METHODS OF OBTAINING OXYGEN GAS
Year: 1863

page_text: LETTERS PATENT to John Robbins, of 872, Oxford Street, in the
County of Middlesex, Operative Chemist, for the Invention of "IMPROVED
METHODS OF OBTAINING OXYGEN GAS."
Sealed the 27th May 1864, and dated the 4th December 1863.
PROVISIONAL SPECIFICATION left by the said John Robbins at the
Office of the Commissioners of Patents, with his Petition, on the 4th
December 1863.
I, JOHN ROBBINS, of 372, Oxford Street, in the County of Middlesex,
Operative Chemist, do hereby declare the nature of the said Invention
for "IMPROVED METHODS OF OBTAINING OXYGEN GAS," to be as follows:-
This Invention relates to improvements in the treatment of certain
substances containing oxygen, whereby that gas is separated therefrom in a
simple and economical manner. Peroxide of barium is combined with
chromic acid or its compounds, or with manganic acid or permanganic acid,
or their compounds, or with peroxide of manganese, or with peroxide of
lead; dilute hydrochloric acid, sulphuric acid, or nitric acid, or any other
acid possessing similar or equivalent properties, or bisulphate of potash is
then added to the mixture, so formed as aforesaid in the proportion of four
parts of the acid to one part of the mixture; or if the bisulphate of potash is
employed the same should be combined with the before-mentioned mixture
in equal proportions, about eight parts by weight of water being afterwards
added to the substances thus combined. The whole having being placed in

page_text: a suitable vessel or receptacle, oxygen gas will be evolved, and which may be
collected over water in the ordinary way. Instead of proceeding as above
described, the acid or bisulphate of potash and water may be dispensed
with, the mixture, so formed as aforesaid, of peroxide of barium with one of
the substances herein-before referred to being placed in a dry state in a
retort or other suitable receptacle. Heat being then applied by any of the
known methods suitable for the purpose, oxygen gas will be given off, and
may be collected in the usual manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Robbins in the Great Seal Patent Office on the 4th
June 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ROBBINS, of 372, Oxford Street, in the County of Middlesex, Operative
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of December, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-seventh
year of Her reign, did, for Herself. Her heirs and successors, give and grant
unto me, the said John Robbins, Her special licence that I, the said John
Robbins, ny executors, administrators, and assigns, or such others as I,
the said John Robbins, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVED
METHODS OF OBTAINING OXYGEN GAS," upon the condition (amongst others) that
I, the said John Robbins, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Robbins, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment, that is to say:-

page_text: My said Invention relates to improvements in the treatment of certain
substances containing oxygen, whereby that gas is separated and evolved
therefrom in a simple and economical manner. As various substances may
be employed for producing the same results in accordance with the principles
of my Invention, I will in the first instance describe the method which by
preference I employ for the production of oxygen. In the first place I form
a compound by combining peroxide of barium with bichromate of potash, in
the proportion of two parts by weight of the former to one part of the latter.
The compound thus formed is then placed in a glass flask or bottle, or other
suitable receptacle provided with an exit tube, and sulphuric acid diluted with
seven parts of water to one part of acid is poured upon the compound, in the
proportion of eight parts of the dilute acid to one part of the compound. The
strength and quantity of the dilute acid may be varied according as it is
desired that the process shall be performed slowly or with rapidity.
The result of this operation will be that oxygen gas will be evolved from
the substances thus combined, and which gas may be collected over water or
mercury in the ordinary way. In cases, however, in which it is desirable that
the oxygen should be obtained with greater rapidity than is possible by the
method I have described, its evolution may be accelerated by adding a small
quantity of hydrochloric acid to the dilute sulphuric acid.
As I have before remarked, substances other than peroxide of barium and
bichromate of potash may be employed for the production of oxygen in
accordance with my said Invention. For instance, peroxide of barium may
be replaced by any other peroxide capable of forming peroxide of hydrogen;
as, for example, the peroxides of potassium, sodium, strontian, and calcium,
but in consequence of the high price of these substances they are practically
inapplicable, peroxide of barium being the only suitable substance which can
be easily and cheaply prepared. Again, instead of the bichromate of potash
other combinations of chromic acid, and also manganic acid and permanganic
acid, and their compounds, as, for example, manganate or permanganate of
potash may be employed, as may also the peroxide of manganese and peroxide
of lead, but in practise the bichromate of potash is, so far as my experience
will enable me to form an opinion, much to be preferred to any other
substance.
I should also remark that although I have spoken of dilute sulphuric acid,
with sometimes a small addition of hydrochloric acid, as being used for the
purposes of my said Invention, yet in lieu thereof dilute hydrochloric acid
alone, or dilute nitric acid, or any other acid possessing similar or equivalent
properties may be employed, the degree of dilution corresponding with that

page_text: before directed with regard to sulphuric acid, and a similar or equivalent
proportion being added to the compound of peroxide of barium and bichromate
of potash. If desired, the acid may be altogether dispensed with, bisulphate
of potash being substituted for the same. In this case equal proportions of
the mixture of peroxide of barium and bichromate of potash, and of the
bisulphate of potash should be mixed, about seven or eight parts of water
being added to the substances thus combined.
Another mode of obtaining oxygen gas is to place the mixture of peroxide
of barium and bichromate of potash, or their analogues as herein-before
mentioned, in a dry state in a retort or other suitable receptacle, and then to
apply heat thereto by any of the known methods suitable for the purpose,
when oxygen gas will be given off, and may be collected in the usual manner.
I may here observe that I am well aware that the evolution of oxygen from
the peroxide of barium alone when heated to redness has been known to
chemists for a considerable period, but the process has been practised in the
laboratory as a matter of experiment only, and is wholly inapplicable to the
ready production of oxygen for practical purposes.
By the simple methods which I have herein-before described as constituting
my said Invention, oxygen gas can be readily and quickly obtained with the
aid of very little apparatus, and that of the simplest character, and the
processes can be carried out by persons unused to chemical manipulation
with the certainty of successful results.
Having thus fully declared and ascertained the nature of my said Invention,
and also the manner in which it is to be performed, I would observe in
conclusion that what I consider novel and original, and therefore claim as
constituting my said Invention is, the combination and treatment of the
substances herein-before mentioned, or their chemical equivalents or analogues,
in the manner and for the purposes herein-before substantially set forth and
described.
In witness whereof, I, the said John Robbins, have hereunto set my
hand and seal, this Fourth day of June, in the year of our Lord One
thousand eight hundred and sixty-four.