66

British Liquid Air Company Ld. v. British Oxygen Company Ld.
British Oxygen Company Ld. v. British Liquid Air Company Ld.

Canadian Patent published in an abridged form in England at the Patent Office
Library, on or about the 25th of April 1902, in the Canadian Patent Office
Record, Vol. 30, No 1, January 31st, 1902); Thrupp (No. 18,913 of 1900). The
whole of each of these was relied upon, and the subject-matter of claiming
clauses 1, 2 and 3 was alleged to be anticipated by each. The Plaintiffs stated 5
that they would also refer to the Minutes of Proceedings of the Institution of
Civil Engineers, issued June 1882, Vol. 68, pages 176 to 186, and to the Journal
of the Franklin Institute, Vol. 67, January to June 1874, pages 9 and 10, both
published at the Patent Office shortly after their respective dates.
(2) The
alleged invention as claimed in Claims 1 and 2 had been published prior to the 10
date of the Patent in the following printed books and documents :-Baly on
"Distillation of Liquid Air," an article in the Philosophical Magazine, June
1900, pages 517 to 529 inclusive; communications from the Physical Laboratory
at the University of Leyden, by Dr. H. Kammerlingh Onnes, No. 14, pages 9 to
28, inclusive, December 1894. An article by Dr. Carl Linde, published in the 15
Engineer" for November 13th and 20th 1896; an article by Professor Dewar,
published in the Proceedings of the Royal Institution of Great Britain, Vol. 15,
Part I., No. 90, pages 133, et seq., February 1897; Journal of the Society of Arts
of the 11th of March 1898, pages 375 et seq. The above articles were all published
at the Patent Office Library shortly after the dates of the respective issues. 20
(3) The alleged invention was not the subject-matter for valid Letters Patent,
and was not matter requiring any invention, having regard to the state of
common public knowledge at the date of the Patent and to the prior publications
referred to in that and the preceding paragraphs. The principle of rectifi-
cation was well known prior to the date of the Patent, and had been applied 25
to the separation of liquid or liquefied mixtures containing constituents of
different degrees of volatility, and there was no invention in applying such
principle in the separation of nitrogen and oxygen. It had been applied, for
example, in the manufacture of alcohol, ammonia, and benzene, and that it
was well known at the date of the Patent appeared from the Specifications 30
cited in paragraph 1, and also from the following Specifications and publi-
cations to which the Plaintiffs would refer :-Coffey (No. 5974 of 1830, and
No. 2373 of 1862); Newton (No. 250 of 1865); Pitt (No. 5245 of 1880) ;
Johnson (No. 8290 of 1888); Spence and others (No. 7485 of 1893); Bruchmann
(U.S.A., No. 325,728 of 1885, published at the Patent Office Library, London, 35
on or about the 25th January 1886); Thorpe's Dictionary of Applied Chemistry,
Vol. 1, articles entitled Alcohol, Distillation, Benzene. (4) The Provisional
Specification did not describe the nature of the alleged invention, and the
invention claimed in the Complete was an invention differing from, and
larger than, that described in the Provisional Specification, and differed there- 40
from in that, according to the Provisional Specification, the compressed air was
liquefied by the heat which it imparted to the liquid air in the rectifying
column, a portion of the liquid air being thereby evaporated, whereas, according
to the Complete Specification, the liquefaction and evaporation did not take
place in the column.

On the 19th November the Plaintiffs obtained leave to serve notice of Motion to include in the Particulars of Objections the Specification of the Canadian Patent of Le Sueur, instead of the abridgment given in the Particulars, and the Motion was ordered to come on with the trial.

45

The Drawing given on p. 231 is a copy of the Drawing " W.R. 1." referred 50 to in the judgment as showing the process that the Plaintiffs proposed to employ. The original Drawing was lettered.

The hearing was resumed on the 21st of November 1907.

Cripps K.C.-Oxygen boils at about 182° C. (91° absolute temperature) and nitrogen at about 195° C. (77-5° absolute). The first point on the 1902 Patent 55

British Liquid Air Company Ld. v. British Oxygen Company Ld.
British Oxygen Company Ld. v. British Liquid Air Company Ld.

is whether or not the method of rectification, which is added as an improvement on the 1895 Patent, is an invention, having regard to the prior

Specifications and the prior knowledge. The second is whether, if the Speci

fication is construed as being limited to the rectifier in a particular combination,

British Liquid Air Company Ld. v. British Oxygen Company Ld.
British Oxygen Company Ld. v. British Liquid Air Company Ld.

the Plaintiffs have taken that. The 1902 Patent is an improvement on the
1895 Patent, and the two have to be considered together. There is no novelty
in what is called the principle of exchange or interchange. The use of a
rectifier per se dates from 1830. The Plaintiffs use a rectifier, but not in
connection with the combination in connection with which it is claimed in 5
the 1895 Patent. In the Drawing the gases escape through the lids, which
must be loose, or there need not be lids at all. One of the methods
indicated by Solvay (Fig. 4) consists in only using the compressed air when it
expands for a cooling purpose-that is called the method of internal work, and
is found in Linde of 1895; the other method (Solvay's, Fig. 3) consists in using 10
the compressed air for what is called outside work, and when it has done
its work, instead of turning it to exhaust, turning it into contact with the
tube containing compressed air, on which it has its cooling effect. The Plaintiffs
adopt the latter process; the Defendants adopt the former. Linde's form of
rectifier is to be found in Coffey's Specification for distillery purposes, and the 15
same method, as applied to oxygen and nitrogen, occurs in Hampson's 1896
Specification. Pictet of 1901 (United States, No. 677,323) also deals with the
separation of gases; it claims the apparatus; the other Specification of Pictet
(No. 683,492) claims the process. Pictet, in his French Specification, deals, in
in terms, with the rectification of air. He says that it is necessary to divert the 20
mind from the distillery process, which is referred to by Linde as though he
had applied that to a particular method. The Plaintiffs have given notice of
Motion to amend the Particulars by including the French Specification of Le
Sueur (No.301,300). [ Walter K.C.-That Specification has never been published;
from inquiries made at the Patent Office in France, it appears that the document 25
has never been printed in France. If it is to be referred to, that must be on the
terms of an adjournment and on terms as to costs. Experiments would have to
be made and they can only be made with difficulty.] In Thorpe's Dictionary
rectifiers are dealt with. There is no infringement; the Defendants separate
the oxygen and nitrogen in the rectifier itself, and there only; the Plaintiffs' 30
rectifier does not separate at all; it further purifies the already separate matter.
The 1905 process effects separation of the constituents in liquid form, more or
less; the Defendants' process effects rectification, and not the separation of the
liquids. The 1895 Specification mentions fractional vaporisation; the Plaintiffs
have no fractional vaporisation in that sense at all. The Plaintiffs have taken 35
the old principle of the falling liquid and rising vapour, and applied it to a
different combination, and with a different result, because they get the pure
nitrogen and the whole of the oxygen ultimately, and the Defendants do not.

Evidence was given in support of the Plaintiffs' case. Sir W. Ramsay said that in Linde's Patent of 1895 there was nothing in the nature of rectification. 40 Coffey's method combined a number of rectifications in one-each tray might be considered as a still. In Hampson's Specification of 1896 rectification took place in the flow of the liquid down the shelves-the principle was the same as in Coffey and as in Fictet. The abridgment of Le Sueur's French Specification would enable one to put his invention into practice. A chemist of ordinary 45 experience would use fractional distillation to separate the constituents of the air-meaning by "fractional distillation" a counter-current of gas upwards and liquid downwards, in contact with each other, and using glass balls, as Linde did. In Linde of 1902 there was no principle that was not shown in the other documents referred to. The Patent of 1905 had no resemblance in principle to 50 Linde's of 1902. The process was the inverse of fractional distillation-it was fractional condensation; in the former process one started with a liquid and condensed the gas, in the latter one started with the gas and condensed it. The Drawing marked "W.R. 1" showed, in the lower part, the Plaintiffs' 1905 Patent, and in the upper part their Patent of 1903. Except the principle of 55

British Liquid Air Company Ld. v. British Oxygen Company Ld.
British Oxygen Company Ld. v. British Liquid Air Company Ld.

rectification, there was nothing else in it similar to the process shown in Linde. In fractional distillation under ordinary circumstances the matter was made easier by the fact that the temperature of the atmosphere was lower than the boiling-point of the substances distilled. If the rectification column in the 1902 5 Patent was sufficiently long, the evaporation could be effected there just as well as it would be in the vessel below. There was a Specification in which the method of fractional evaporation was proposed before Linde of 1895-Parkinson of 1892. There was not in G2, of Linde 1895, a fractional distillation, which term, technically, implied repeated distillations; the process employed would be 10 better described as fractional evaporation. The witness did not agree with Sir J. Dewar's published statement that the liquefaction of oxygen and nitrogen, at the partial pressures in which they exist in the atmosphere, was simultaneous. In Hampson's Specification of 1896, and in Pictet (No. 677,323) the word "rectification" did not occur, but the apparatus involved that process. Pictet 15 copied Coffey's still, and made an apparatus that would give at will oxygen, either pure or mixed with nitrogen. He obtained liquid air and rectified it. Linde, in his 1895 Patent, did not liquefy air in V. The idea of using, under circumstances of extreme cold, of the familiar method of rectification, did not involve much ingenuity.

20

René Jacques Levy, managing director of the Plaintiff Company, said that the term rectification had a special technical meaning; in it one necessarily had a gas passing in contact with a liquid that was going in a direction opposite to that of the gas, and there was an exchange taking place between the liquid and the gas. There was the fractional element in the Defendants' 1902 Patent, as 25 well as in their 1895 Patent. Hampson's process could be worked without difficulty. As to Le Sueur's Canadian Patent, there would be no difficulty in constructing the rectifying column; so far as rectification was concerned, every element in Le Sueur occurred in Linde. Linde liquefied the air, separated by rectification, and completed rectification by fractional evaporation; Claude 30 separated the air during liquefaction, and completed the separation by rectification, and so was able to produce pure nitrogen. In Claude's Patent of 1903 there were the vessels s and t of Linde.

Sir W. Ramsay, re-called, said that in the Patent of 1902 there was separation of oxygen and hydrogen by boiling-off, but in Claude's process there was no 35 separation in the vaporiser, which contained oxygen only. There were, roughly, two methods, viz., boiling-off, which was Linde's original method, and by which one got liquid rich in oxygen; the other method was by fractionationby having a fractionating tower, which was common to Linde and Claude, but in Claude's process there was no boiling-off. It was a surprising thing that 40 Claude's process gave such pure nitrogen, and it required research to ascertain that his discovery had been made. The method of rectification in W.R. 1 was the same as was indicated in Claude's 1903 Specification. Claude began the separation from the liquefaction, but he could carry it much further than Linde; he obtained pure nitrogen, which he utilised to deprive the air of all 45 its oxygen; Linde allowed 7 per cent. of oxygen to escape under favourable

circumstances.

R. J. Levy, re-called, said that Linde, in his 1895 Specification, spoke of his process sometimes as fractional distillation, sometimes as fractional evaporation. Linde's apparatus of 1902 could make pure oxygen, but if there was a rectifying 50 column into which vapour containing nitrogen was sent, pure oxygen could not be obtained. Linde boiled the oxygen in a separate vessel, and that made a difference of principle. The Claude Company had opposed one of Linde's Patents in Germany, but, after an experimental proof of the Pictet apparatus, the Patent had been granted. By working Pictet's apparatus one could obtain less 55 than by simple evaporation; it depended on how the apparatus was worked.

British Liquid Air Company Ld. v. British Oxygen Company Ld.
British Oxygen Company Ld. v. British Liquid Air Company Ld.

Commercial oxygen, as prepared by Brin's process, contained 85 to 95 per cent. of oxygen. The maximum that could be obtained with Thrupp's apparatus was 48 per cent. Rectification was the exchange between a vapour mixture and a liquid mixture. In Pictet's apparatus the theoretical minimum of oxygen, mixed with the nitrogen, producible was 7 per cent.

At this stage of the action it was agreed between the parties that the Defendants would not raise any question as to whether there had been technical threats or not, that the matter should be dealt with as if a cross-action for infringement were being brought by the Defendants, and that neither party would ask for damages.

5

10

Walter K.C. opened the Defendants' case.-Rectification means purification; one speaks of rectified spirit, as meaning pure ethyl alcohol. Prior to 1895, rectification of air had been carried out by a series of progressive coolings, but no one had succeeded in carrying out the suggestions in the Specifications of Siemens and Coleman. Linde was the first who produced liquid air by the 15 self-intensive process-by the system of counter-current interchange. From 1895 to 1902 the whole progress of invention consisted in one thing onlyrepeating V2 several times and refractionating the liquid obtained, Rectification alone is not enough; it has to be worked in a way the reverse of that in which it had been worked before. In ordinary rectification there is an un- 20 limited supply of external cold, colder than the boiling-point of the most volatile element, and there are common sources of external heat. To obtain liquid oxygen, the problem was, as though one had to work the Coffey still in a red-hot room, without any cold except what there was in the apparatus itself. In solving the problem, compressed air was liquefied by passing it through a 25 counter-current flow apparatus, cooled by the evaporation products of the liquid in the rectifying column. That had never been done before. Then the products passed, at a slight pressure, into tubes contained in a vessel in which the liquid was to be boiled. To make up for the loss due to the entrance of external heat, Linde says one can either send in liquid by the 1895 apparatus, 30 or increase the pressure on the pumps h and i. As to infringement, Claude has made an addition; the rectifying process is the same, but it is carried further. He has bent the pipes in the bottom vessel and thereby they enrich the liquid with oxygen by a preliminary scrubbing in the vertical tubes, and then they condense the rest of it in the downwardly flowing tubes. For the purpose of 35 Linde 1902 that may be an improvement, but it is a mere addition to, not an alteration of, his process. It is said that the Plaintiffs pass up part of the products of evaporation, but Linde passes up the whole of the products. The distinction is merely, that the Plaintiffs make the surface of the condensing apparatus large enough in one vessel to cool the necessary liquid; the Defen- 40 dants put the condensing surface in two vessels. The distinction is not essential. As to the history of invention between 1895 and 1902, even assuming that Hampson, Pictet and Le Sueur would work, they have all placed evaporation coils right through their apparatus-they have used repeated distillation.

Evidence was given in support of the Defendants' case. J. Swinburne said 45 that Linde first realised, that if one compressed air under very great pressure and let it expand inside something where heat could not get to it from the outside, it must eventually become cold enough to liquify some of the air. Before his Patent of 1895 no one had been able to obtain liquid oxygen by any mere method of expansion and interchange. Linde realised, that if he boiled the 50 liquid air, using the coldness of the coming-off gas to cool that coming in, he could distil under cold conditions. In the Specification of 1902 the bottom of the rectifying column was about the temperature of boiling oxygen, and the top was about the temperature of boiling nitrogen; there was a gradation controlled by the exchange. The rest of the apparatus, until one reached the rectifier, only 55