was then set out in which the proportions of the substances by weight were given.

Second process:-"Naphthylamine is converted into its diazo compound as before stated, and equal molecules of the diazo compound thus obtained and of the sulphoacids of either alphanaphthol or betanaphthol are allowed to react upon each other, by preference in an alkaline solution;" red colouring matters result, and may be obtained by precipitation or evaporation. The above sulphoacids are produced by heating naphthol with excess of sulphuric acid at a temperature of about 100° C. The product is a mixture of several naphthol sulphoacids. As the process may be applied to the other sulphoacids (besides monosulphoacid of naphthol) which result from the treatment of naphthol with sulphuric acid, the invention under the second process "is the action of the diazo naphthaline upon all sulphoacids of either alpha or beta naphthol, and substantially in the manner aforesaid." An example of the second process was then given.

Third process :-"The sulphoacids of naphthylamine are converted into their respective diazo compounds, and equal molecules of the diazo compounds thus obtained and of either alphanaphthol or betanaphthol are allowed to react upon each other, by preference in an alkaline solution, and substantially in the manner above described in the first and second processes." Alphanaphthol produces brown dyes, and betanaphthol red. No known ways of producing the said sulphoacids of naphthylamine are mentioned. "By the said methods, as is well known, several modifications of the sulphoacids of naphthylamine are obtained, chiefly differing from each other by their various degrees of solubility in water, some of them being nearly insoluble, such as the so-called naphthionic acid.” Examples of this process are next given, in which naphthylamine is directed to be "mixed or dissolved" in strong muriatic acid. The colours obtained

differed in a similar ratio in their various degrees of solubility.

A fourth process was then described.

The claims were

"First, the production of red and brown colouring matters, which in chemical language may be termed the sulphoacids of oxyazonaphthaline, by the action of the diazo compounds which may be prepared from naphthylamine or from the sulphoacids of naphthylamine upon any of the isomeric naphthols, or of mixtures of the same, or upon any of the sulphoacids which may be prepared from either alphanaphthol or from betanaphthol or from mixtures of the same, substantially by the processes above described.

"Secondly, the production of similar colouring matters, and which in chemical language may be termed the sulphoacids of dioxyazonaphthaline, by substituting dioxynaphthaline for either of the two isomeric naphthols in any of the processes above described for the preparation of the sulphoacids of oxyazonaphthaline, substantially as hereinbefore described."

An objection on the ground of alleged absence of utility was based on evidence showing that out of all the dyes produced only one was commercially useful, as it was of a bright colour, and took the public fancy,

although the descriptions were correct as to the process producing other shades of colour for which there turned out to be no market. And also on the ground that there was no means of knowing beforehand the shades that would result.

At the date of the patent there were two isomeric naphthylamines, alpha-naphthylamine and beta-naphthylamine; the former would produce the required result, the latter not. The point was raised that this constituted insufficiency of direction. But it was proved that the alpha-naphthylamine had been known for fifteen years, and the beta-naphthylamine for only two; and that a chemist would ordinarily use the term naphthylamine to denote the older form, and speak of the beta-naphthylamine as the "new naphthylamine."

The directions as to the first process were objected to as being misleading, as there were some organic sulphoacids which could be prepared by using ordinary sulphuric acid at a temperature lower than 100° C., at which temperature the sulphuric acid would not convert the oxyazonaphthaline into sulphoacids. It was contended, however, by the patentee that it would be an unreasonable construction of language to hold that the specification asserted that every degree of strength of sulphuric acid and of temperature which would suffice for the preparation of the sulphoacid would convert the azo compounds into their sulphoacids.

The directions for the second process were alleged to be misleading, since it was stated that red dyes would result, whereas the dyes were brown or red according as alpha- or beta-naphthol was used. But shades of red and brown run into one another, and may be differently described by different people; e.g. "brownish red," "reddish brown," &c.

The third process was alleged to be misleading because the most useful dye, producing the brilliant red colour,1 was formed from the insoluble sulphoacid, and the specification did not call attention to this, but tended. to lead the reader away from trying the insoluble sulphoacid. Against this it was urged that the third process referred to the other two, in which "mixing" was spoken of as well as "dissolving," and that the word "solution" therefore included an intimate mixture of powdered solid dusted into the liquid; and also that the use of insoluble sulphoacids was distinctly included in the language describing the process.

At the trial of this action for infringement of the above patent it was held that it was valid, and that the defendant had infringed.

This dye is that known as Fast Red B.T., which is the sodium salt of a-naphthalene-azoB-naphthol-monosulphonic acid, viz. C20H13N2O4SNa. Its constitutional formula, according

to Schultz & Julius, is C1,H,(a)N=N[1]C10Hs JOH[2]

Sisley as

N N

OH

{NaSO3[6]' but is given by Seycwetz &

NaSO3

This decision was reversed by the Court of Appeal, on the ground that the patent was invalid, because the specification did not distinguish what was useful and what not, the third process being misleading, and the use of the term "naphthylamine" (without distinguishing "alpha" from "beta") ambiguous.

On appeal to the House of Lords.

Held, that the claims included all the different isomers described as "sulphoacids of oxyazonaphthaline," which are red or brown dyes, and which are produced from the action of the diazo compounds prepared from naphthylamine or from the sulphoacids of naphthylamine upon the isomeric naphthols, or upon any of the sulphoacids which may be prepared from either alphanaphthol or betanaphthol, or from mixtures of the same. Also that the several objections to the patent failed, and that it was valid.

Per Lord Halsbury, L.C. (p. 462): "There is certainly authority for saying that an invention must be useful, although that word is not found in the statute. . . . The element of commercial pecuniary success has, it appears to me, no relation to the question of utility in patent law generally, though of course where the question is of improvement by reason of cheaper production, such a consideration is of the very essence of the patent itself, and the thing claimed has not really been invented unless that condition is fulfilled."1

Per Lord Herschell (466): “I do not think it is a correct test of utility to inquire whether the invented product was at the time of the patent likely to be in commercial demand or capable of being produced at a cost which would make it a profitable speculation to manufacture it. . . . The products which result from the appellant's products are, no doubt, of varying worth, but one at least has proved to be of great commercial value, and it is not shown that any of them are incapable of being used effectually for the purpose of dyeing." 2

As to sufficiency of directions (p. 467): “But I think the patent under consideration does show how the colouring matters are to be produced, and that what it leaves a skilled person of the class, to whom the specification is addressed, to discover is only which of these colouring matters will best answer his purpose at any particular time. There is, in my opinion, no warrant for asserting that this invalidates the patent.'

113

1-2 The foregoing portions of judgments have been quoted in Siddell v. Vickers, 5 R. P. C. 96, and referred to in Kurtz v. Spence, 5 R. P. C. 182, as being the latest exposition of the law on this point. Also quoted and followed by Buckley, J., in Atkins & Applegarth v. Castner-Kellner Alkali Co., 18 R. P. C. 296.

This case is quoted to show that "useful" means useful for the purpose indicated by the patentee: Lane Fox v. Kensington, &c. (per Lindley, L.J.), 9 R. P. C. 417.

3 See also Edison & Swan v. Holland, 6 R. P. C. 284.

1888. KAYE 7. CHUBB & SONS, 5 R. P. C. 641.

Alleged Anticipation-Earlier device a failure.

A patent (No. 4873 of 1877) was granted to Messrs. Kaye for "improvements in the means or apparatus employed for fastening and unfastening doors, gates, lids, and windows."

For the present purpose it will be sufficient to refer only to the followportions of the specification:

"At Figs. 1 and 2 a is the shell or framework of the door-fastener, in which we provide the finger or segment b, which is fitted so as to move radially on the stud or pin c, and to project when at rest through the front plate d, as shown at e, for the purpose of inserting itself into the catchplate f, as shown at Fig. 1, in the door-frame or jamb g.

FIG.I

FIG. 2.

From Kaye's specification (No. 4873 of 1877).

"For the purpose of actuating the finger or segment b we provide a lever, h, which is pivoted or mounted on a pin or stud, i, within the shell or framework a. In order to retain the finger or segment b in the projecting position, as shown at e, we provide the spiral spring j, or other equivalent means; by this arrangement the segment or finger b (except when moved inwards. by the lever h in the manner hereafter described) always remains in the position shown at e. In all cases we avoid coupling the lever h by any rigid connection to the forefinger or segment b.

"In order to actuate the lever h we engage the inner end k, which has a projecting piece, 7, with a spindle, m, on which is provided the projection or collar n, against which the end k of the lever h remains in contact. For the purpose of more conveniently moving the spindle m we provide knobs o and o1, which are screwed or otherwise fastened on to the outer ends thereof. Tho position of such knobs o and o1 on the spindle m varies in accordance with the thickness of the door, and in order to retain these at their required distance apart we provide on the spindle two adjustable nuts or bosses, 1', whose position with regard to the knobs is clearly shown at Fig. 1. . . .

"The mode of operating or working the fastener is as follows:-By pulling a knob, o, or pushing at o1, the spindle m provided with the collar " is moved in the direction shown by arrow. The collar ʼn being in contact with the end of the lever h, causes it to transmit motion to the finger or bolt B, and thereby withdraws it upon the catch-plate ƒ and clear of the

loose runner or roller v, and by a continued pulling or pushing of the knobs in the direction shown the door may be opened after the finger or segment is withdrawn.

"By having no rigid connection between the segment or finger b and the lever h, the door may be closed through the means of the knobs or handles, or it (the door) may be closed without moving the knobs or o1....

"We hereby declare that we make no general claim to the opening of latches or fasteners by a pull or push of a spindle or knob, but we claim :— The construction of a latch or fastener wherein a lever worked by the push or pull of a spindle or knob moves in one direction only a segment or finger turning on a fulcrum and pressed in the opposite direction by a spring so as to engage with a catch-plate, substantially as and for the purposes herein set forth."

In an action for infringement against the defendants the validity of the patent was contested, inter alia, on the ground that the invention was anticipated by Imray's specification (No. 1160 of 1871).

For the present purpose the following description is sufficient1:— "Another object of my invention is the construction of a spring-latch

in such a manner that it is disengaged from the catch-plate (f) by pulling the knob or handle on the side towards which the door opens, or by pushing the knob or handle on the other side. Thus the act of pulling or pushing the knob without turning it round serves to open the door. For this purpose the knob-spindle (d) is made with a groove in it (d, b, Figs. 8 and 13), or with a projection or collar on it, which engages with a lever (b) connected to the spring-bolt (a). The knob-spindle being pulled or pushed in the

1 The passage here quoted had in the original no references to the diagrams, which are given from another part of the specification.