marked ʊ, may be employed; el is an earthenware or metal continuation of the tube d1, such tube e1 being perforated if found desirable for causing a portion of the heated air to be more equally supplied to the interior surface of the flame."

The air entered at the outer circumference under the cover, part decended along the surface of the glass b, keeping it cool, as shown by the arrows, and part through the inlets k, along the reflector g, thence upwards and through openings under line AB and down the tube d1, through per

Fig. 6

Fig. 5

Diagrams from Clark's specification (No. 2869 of 1881).

forations at bottom of e, and so on to the upper or inner side of the circular series of gas-jets from v, supplied by the central gas-pipe u.

The claims were:

"Firstly, the general arrangement and construction of the improved lamp hereinbefore described and represented in Figs. 1 to 4 of the accompanying drawing.

"Secondly, the modified construction of lamp hereinbefore described and represented in Figs. 5 and 6 of the accompanying drawing.

"Thirdly, the method of supplying heated air to the inner surface of the flame by causing such air to pass through the chimney in its passage to the

flame, substantially as hereinbefore described and represented in Figs. 5 and 6 of the accompanying drawing.

"Fourthly, the employment of the perforated continuation

from the chimney for distributing the heated air over the interior surface of the flame as hereinbefore described and represented in Fig. 5 of the accompanying drawing."

The action was for infringement.

Amongst other objections, want of novelty was pleaded and want of subject-matter raised in argument.

Amongst other anticipations, Siemens' specification (2231 of 1879) was
In Fig. 2 the incoming air was heated by passing down outside

relied on.

the central gas-pipe g and the circular chimney surrounding it. Fig. 5 shows an inverted lamp in which the air that is heated enters by inlets o, passes upwards along the middle concentric passage, the chimney consisting of the outer one. But there was nothing to show how an incoming downward aircurrent could be directed to the inner surface of the flame.

Wire diaphragms were also proved to be old. The device was proved to be a great improvement on former lamps.

At the trial the patent was

stituted a patentable invention; that claim 2 included as an element in the combination the cooling current; that claim 3 was for a subordinate integer; and that claim 4 was redundant, a mere repetition of claim 3, and not a substantive claim to the use of perforations.

Lindley, L.J. (at p. 52), pointed out how Siemens had discovered the importance of heating the air before it reached the flame; he showed the advantages of it and how to do it. "That idea is seized upon or adopted naturally by Clark, who is a later inventor-a very valuable idea, because it seems obvious, now that we know all about it, that it was a very important and a very valuable suggestion. . . . Clark's mind was addressed to the particular method of bringing a supply of heated air to particular places on the flame. His step is in advance of Siemens'; he takes Siemens' as far as it goes, and modifies that and produces a new and very valuable result -a brighter flame and a much better result. He so arranges his

concentric ring, or machinery, or tubes, as to bring his hot current down to the middle of the particular kind of flame which he selects for the purposes of his lamp. In addition to this, Clark has availed himself of what Siemens did not, that I know of, that is, the cooling current which kept the temperature of the glass down, and prevented cracking, and so on."

1892. PICKARD V. PRESCOTT, 9 R. P. C. 195.

Prior Publication.

A patent was granted to Messrs. Pickard & Curry (No. 8953 of 1885) for "improvements in the bridges of pincenez, or double eye-glasses."

The patentees brought a note of suspension and interdict in the Court of Session against the respondent, praying that he be interdicted from infringing the above patent.

The chief objection raised was that of prior publication of the patented invention.

At the hearing the following facts were proved. A description of the invention was communicated by a person employed to carry it out in Paris to the Revue Générale d'Ophthalmologie, and there published in the number for June 30, 1885. There was no evidence of the actual date of publication in Paris. The Revue circulated amongst oculists who wished to be informed of the progress made by their profession. A witness, speaking several years after the event, said that he saw the Revue at the time of publication immediately after June 30, 1885; but on cross-examination could not fix the date even to the month of July. It was proved that on August 25 there was a copy in the hands of a gentleman connected with the Middlesex Hospital. A witness at the time of the trial (1889) had in his possession his own copy of the Revue, to which he was a subscriber, and had seen three copies-one at the Royal Ophthalmic Hospital, another at the Ophthalmological Society's, and a third in the possession of a London oculist. There was an entry in the books of the agents in Edinburgh to the effect that they received their copies on July 10, 1885. It was their practice to deliver them at once to subscribers. A subscriber proved that he took the Revue regularly, but he could not recollect at what date he read the number in question, nor whether he was at his usual residence at the time.

Held, by the Lord Ordinary, that prior publication was not proved.
The respondent reclaimed.

Held, by the Inner House that prior publication was established, and that therefore the patent was invalid (7 R. P. C. 361).

On appeal to the House of Lords.

Held, that there was sufficient evidence of prior publication to invalidate the patent, bearing in mind the nature of the invention and the general desire of practitioners to have early information on the subject in question, and in the absence of any evidence on the other side.

1892. KING & Co. v. ANGLO-AMERICAN BRUSH CORPORATION,
9 R. P. C. 313.

Anticipating Specification, Construction and Sufficiency of.

In 1878 a patent (No. 2003) was granted to J. Haddan for “improvements in apparatus for the generation and application of electricity for lighting, plating, and other purposes."

The complete specification was as follows:-1

"My invention relates to electric apparatus for the generating of electricity, and for its application and use in electroplating and in the production of electric light, and for any other purpose to which electricity may be applied. In stating wherein my invention consists, it may be separated into the following divisions: . . . Fourth, a peculiar manner of disposing and arranging the insulated wires and current conductors of the machine."

With regard to the "fourth division" of the invention, the specification pointed out the defect in series-wound dynamos-the cessation of exciting magnetism "on opening" the circuit, the formation of powerful currents only when the external circuit is closed and its resistance not too large. "Such machines are not well adapted to certain kinds of work, notably that of electroplating"-in which industry a counter electromotive force is developed, and may, under certain circumstances, reverse the polarity of the machine. A moderate constant magnetic field would obviate this.

"Other useful applications of a 'permanent field' machine will readily suggest themselves. I attain my object by diverting from external work a portion of the current of the machine and using it either alone or in connection with the rest of the current for working the field magnets. I prefer the latter plan of the two just above mentioned, especially for electroplating machines. . . . In applying my invention to dynamo-electric machines, I wind the cores of the field magnets with a suitable quantity of a comparatively fine wire having a high resistance in comparison with that of the external circuit and the rest of the wire in the machine. The ends of this wire are so connected with other parts of the machine that when the latter is running a current of electricity constantly circulates in said wire, whether the external circuit be closed or not. The high resistance of this wire prevents the passage through it of more than a small proportion of the whole current capable of being evolved by the machine, therefore the available external current is not materially lessened. When this device, which I have called a 'teaser' (E), is used in connection with field magnets, also wound with coarse wire (as shown in Fig. 1 of the drawings), for the purpose of still further increasing the magnetic field by employing the main current for this purpose in the usual manner, then the 'teaser' may be so arranged that the

1 Only those portions are given which affect the ground on which the appeal was decided by the House of Lords. As to the issue of disconformity, see ante, pp. 69, 70.

2 The letter "E" was not in the original, but is inserted to facilitate reference.