in the provisional specification,' and the patent was, therefore, invalid. (Bailey v. Roberton, L. R. 3 App. Cas. 1055, affirming the decision of the Court of Session in Scotland).

The plaintiff's provisional specification stated the invention to be an improved method of treating oils for various applications, and it set forth a particular method of thickening them. The complete specification claimed (1) the particular method of thickening oil limited to lubricating purposes; and (2) the combining of such thickened oils with mineral oils as thereinbefore described. The body of the specification stated that the combining of thickened oils with mineral oil, irrespective of the precise means adopted for thickening them, was part of the invention; that is, the invention was alleged to cover the combining of oils thickened by other methods than by the one claimed by the first claim. It was held by a Judge of the Court of Session, Scotland, that there was a fatal variance between the two specifications. (Hutchison v. Patullo, 4 R. P. C. 332.)

The title of one of Mr. Edison's important patents obtained in this country in the year 1877 was Improvements in instruments for controlling by sound the transmission of electric currents and the reproduction of corresponding sounds at a distance.' In the first part of the provisional specification the description of the invention referred entirely to the transmission of sound or the controlling of sound by means of electric currents; and in the latter part different methods of carrying out this invention under the varying conditions of use were alluded to. The patentee's complete specification described, in addition to the invention known as the Telephone, which was worked by electricity, a very ingenious instrument called the Phonograph, which is a purely mechanical contrivance and has nothing whatever to do with electricity or magnetism, nor has it necessarily anything to do with the transmission of sound to a distance. The inventor described it as a means of recording the sounds produced by the human voice or otherwise by causing the movements of a diaphragm to be registered on paper or soft sheet metal, and then the paper might be

used in an instrument to reproduce the sound upon a delicate diaphragm by giving to the same a vibration similar to that originally given by the voice. The mode of applying the phonograph, a complete instrument in itself, to the transmission of the sounds over a telegraph line was also described. It was held by Mr. Justice Fry, who presided at the trial of an action for the infringement of the patent, that the nature of the phonograph had not been fairly described in the provisional specification, and that the patent was therefore invalid. (The United Telephone Co. v. Harrison, L. R. 21 Ch. D. 746.)

See also Penn v. Bibby, L. R. 2 Ch. 127; Horrocks v. Stubbs, 3 R. P. C. 221; Gaulard and Gibbs' Patent Appeal, 6 R. P. C. 225; King, Brown & Co. v. Anglo-American Brush Corporation, in the Court of Session, Scotland, 6 R. P. C. 414.

An inventor is not bound to describe in his provisional specification any mode of carrying the invention into effect, but if he does this, and if, before lodging the complete specification, he discovers an improvement in such mode, or if he discovers a different mode, he is bound to give to the public in that instrument the benefit of what he has discovered, although there may be improvement and even invention which was not known to him at the time. Per L. J. Cotton, in Woodward v. Sansum (4 R. P. C. 175). And in the same case (p. 178) L. J. Lopes said: It is said the complete specification describes a new and separate invention not covered by the provisional specification. If this can be established the patent would be bad. A provisional specification was never intended to contain a complete and exhaustive description of the invention. It was intended to be sufficiently specific to disclose the nature of the invention so as to protect the inventor until the time for filing the complete specification, but permitting him in the meantime to perfect any details, to modify, supplement, and develop his invention, always keeping within what I may call the ambit of his invention as disclosed in his provisional specification.'

In Bailey v. Roberton (L. R. 3 App. C. 1055) Lord Blackburn said in the House of Lords that it is no objection to the complete specification if it shows that there has been discovery since lodging the provisional, and that something has been added by way of supplement to make the invention really workable, the nature of the invention remaining the same.

Under a patent for improvements in laying down marine telegraphic cables, certain guiding rings for controlling the delivery of the cable were described and claimed in the complete specification, although they were not mentioned in the provisional specification. It was held that the patent was not thereby invalidated. (Newall v. Elliott, 4 C. B. N. s. 269.)

In Lucas v. Miller (2 R. P. C. 155) it was held that matters of detail, even those that had not occurred to the inventor at the time of lodging the provisional specification, may be introduced into the complete instrument, if they give a better method of carrying out the invention or of working it more easily.

These cases show that when an inventor elaborates his invention and renders it specific, when he gives a more particular and detailed description of it in the complete specification, he will be allowed to follow out his original design, and to give a fair development of it, even to the addition of improved methods of carrying it into effect, but he must not make a new departure nor introduce anything that cannot be brought within the meaning and purport of the provisional specification.'

If any part of the invention, as described in the complete specification, does not fall within the title, the patent

In the following cases the patents were attacked on the ground of variance between the complete and provisional specifications, but the objections were overruled in all: Watling v. Stevens, 3 R. P. C. 30; S. C. on appeal, 3 R. P. C. 151; Moseley v. Victoria Rubber Co., 4 R. P. C. 248; Morgan v. Windover, 4 R. P. C. 417; affirmed on appeal, 5 R. P. C. 295; reversed on another point in H. L., 7 R. P. C. 130; Siddell v. Vickers, on appeal, 5 R. P. C. 416; Crampton v. Patents Investment Co., 5 R. P. C. 397; S. C. on appeal, 6 R. P. C. 287; Gaulard and Gibbs' Patent, 5 R. P. C. 532.

will be invalid. Crossley v. Potter, Macr. P. C. 240.) title of a patent was for Certain Improvements in the Doors and Sashes of Carriages,' and the patentee, in his specification, said, 'I have shown my invention as applied to railway-carriage doors and windows, although they are equally applicable to the doors and windows of any other description of carriage, or in any position where doors and windows are subject to jar and vibration,' this was held not to extend his claim beyond the title (Oxley v. Holden, 8 C. B. N. s. 707). See also Newall v. Elliott (10 Jur. N. s. 954).

(Croll v. Edge, 9 Scott, C. B. R. 479; However, where the

A patentee will not be allowed to read the provisional specification with the view of aiding or supplying a defect in the complete specification. (Mackelcan v. Rennie, 13 C. B. N. s. 52.)

RULES TO BE OBSERVED IN PREPARING SPECIFICATIONS.

Good Faith.-The first thing that an inventor about to prepare his specification should bear in mind is, that he is bound to act with good faith. There must be no studied ambiguity or equivocal language; no attempt to keep anything secret; he must take the public into his confidence, and make a full disclosure of his invention; and the whole statement must be fair, open, explicit, and honest. If he acts in any other manner, it will go hardly with him when his specification comes to be examined in a court of justice.

Definition of the Invention.-The next point to be attended to is the accurate definition of the invention, so that the reader may clearly understand of what it consists. In the case of Macfarlane v. Price (1 Stark. 199; 1 W. P. C. 74), Lord Ellenborough said that the patentee in his specification should say, My improvement consists in this; describing it by words if he can, if not by reference to figures. But here the improvement is neither described in words nor by figures. . . . A person ought to be warned by the specification against the use of the particular invention, but it would exceed the wit of man to discover from what he is warned in a case like this.' 'Every party' (said Cresswell, J.,

in Gibson v. Brand, 1 W. P. C. 640) is bound to tell the public clearly by his specification what he claims, and what they may do or not do without risk of an action for infringing his patent.'

In Philpott v. Hanbury (2 R. P. C. 33), the patent was held bad because the patentee had not told the public the nature of the invention in reasonably accurate language.

It forms a condition' (said Mr. Justice Grove), without the fulfilment of which the patent is void, that the patentee should state the nature of his invention, in order that persons reading his specification should know, and should know with reasonable clearness and facility, what they are prohibited from using by the letters patent without his permission or licence.' In regard to the specification before him, the learned judge said that he could not satisfactorily frame any formula of words which would describe or reasonably define what the nature of the invention was. • The specification has not disclosed what is the real nature of the invention which the patentee says he has made.'

And again, in Fairburn v. Household (3 R. P. C. 128, S. C. affirmed on appeal, 3 R. P. C. 263), a patent was held invalid because the specification did not indicate with anything approaching to clearness or certainty what it was that the patentee claimed as a novelty, what it was that he relied on as the real invention he sought to protect. (And see also Rowcliffe v. Morris, 3 R. P. C. 17.)

A patentee sometimes obtains a second patent for improvements upon an invention which formed the subjectmatter of a previous patent, and the second specification usually refers to the first. Care should be taken in preparing the second specification to make it distinguish clearly the later improvements from the earlier invention. (Eades v. Starbuck Waggon Co. W. N. 1881, p. 160.)

When the invention is partly original and partly communicated from abroad, it would seem desirable that the respective parts should be distinguished in the specification. (Renard v. Levinstein, 10 L. T. N. s. 177.)

In the case of a patent for an invention communicated

I