that the patentee had in the interval between the dates of lodging the two specifications, and therefore before the date of his patent, publicly exercised his invention and sold the products.

By the fourteenth section of the Patents Act of 1883, where an application for a patent in respect of an invention has been accepted, the invention may during the period between the date of the application and the date of sealing such patent be used and published without prejudice to the patent to be granted for the same; and such protection from the consequences of use and publication is termed provisional protection.

This protection, however, gives the applicant no rights against the public. He is only protected against the consequences of his own publication in case of his employing workmen, making experiments, or exercising the invention (Ex parte Bates & Redgate, L. R. 4 Ch. 577); that is to say, he will not thereby prejudice the patent afterwards granted to him. He must not forget, however, that as he cannot take any legal proceedings for infringements committed before the publication of the complete specification (sect. 13), his dealings with the invention even under protection should be conducted with due caution.

CHAPTER IX.

THE COMPLETE SPECIFICATION.

WHETHER there ever existed an implied compact between a patentee and the public with regard to a disclosure of the invention, as many lawyers formerly supposed and some doubted, is a question which it is unnecessary to discuss in these pages. It is sufficient for all practical purposes to say that the Patents Act of 1852 imposed upon every patentee the duty of particularly describing and ascertaining the nature of the invention, and in what manner it was to be performed; and that the Patents Act of 1883 has laid upon every applicant a like obligation in identical language (sect. 5, subs. 4). The instrument by which the applicant undertakes to satisfy the requirements of the law is known as the Complete Specification. It is by this instrument that the public are made acquainted with the inventor's secret, and he is bound to describe it clearly and fully, with the view of enabling others, when the proper time comes, to work the invention if they desire to do so. In the meantime the public are entitled to know what it is they are prohibited from using, that they may not unawares incur liability.

The reader will perceive before he arrives at the end of this chapter that the security of a patentee's privileges largely depends upon the shape given to this instrument. It is therefore necessary that he should exercise the greatest care and circumspection in its preparation. As Sir George Jessel, then Master of the Rolls, once remarked in court, it is very difficult to draw a complete specification.' And the judges on the bench very frequently complain of the ambiguities, obscurities, and other defects of the specifica

tions that go before them, not only rendering the task of interpretation difficult, but putting in peril the whole edifice which the patentee has laboriously built. It may be thought, perhaps, that after the document has passed the ordeal of official examination no further question ought to arise as to its sufficiency. An inventor, however, should not place too great reliance upon this, but should adopt every means in his power to make not only the complete but the provisional specification perfectly correct, and in accordance with both the letter and the spirit of the law, that they may, if at any time disputed, be held good upon their own merits.

After an account of the procedure has been given the greater part of this chapter will be devoted to a statement of the rules by which the inventor should be guided in preparing this important instrument. These rules will make him acquainted with the chief requirements of the law, and will put him on his guard as to the faults which he is most likely to commit. Our remarks will be supported throughout by references to the reported cases.

PROCEDURE.

We have seen in the last chapter that, by the fifth section of the Patents Act of 1883, an application for a patent must be accompanied by either a provisional or a complete specification. In the great majority of cases an inventor needs further time for making experiments and testing the invention with a view to its improvement and the working out of details, all which may be safely done under the protection of a provisional specification; but if he lodges the complete instrument at the time of application he deprives himself of the opportunity of improving the invention, and of adding, perhaps greatly, to its value. Moreover, inventors who wish to obtain patents in other countries should bear in mind that the previous publication of an invention by a complete specification in this country may be a bar to a valid patent unless the case is one that

falls within the operation of the fourth Article of the International Convention as to Patents.

The complete specification, whether left on application or subsequently, must, in the words of the Act, particularly describe and ascertain the nature of the invention, and in what manner it is to be performed, and must be accompanied by drawings if required.' It must commence with the title, and must end with a distinct statement of the invention claimed. The form of the instrument is Form C, given in the second schedule of the Patents Rules, 1890.1 If left with the application (sect. 6) the papers are referred by the Comptroller to an examiner, whose duty it is to ascertain and report to the Comptroller whether the nature of the invention has been fairly described, and whether the application, specification, and drawings (if any) have been prepared in the prescribed manner, and the title sufficiently indicates the subject-matter of the invention. If the examiner reports in the negative, the Comptroller may require the application, specification, or drawings, to be amended before he proceeds with the application, subject to appeal to the law officer, who, after hearing the applicant and the Comptroller, may make an order determining whether, and subject to what condition, if any, the application shall be accepted. When an application has been accepted, the Comptroller will give notice thereof to the applicant.

If the applicant (sect. 8) does not leave a complete specification with his application, he may leave it at any subsequent time within nine months from the date of application. But by the third section of the Act of 1885 the Comptroller has power to extend the time for another

A fee of 47. is payable on filing a complete specification with the application: if filed afterwards the fee is 37. As to the size of paper, &c., see the footnote on page 106.

2 Whenever the last day for leaving a document at the Patent Office shall happen to fall on Christmas Day, Good Friday, or on a Saturday or Sunday, or on a day observed as a holiday at the Bank of England, or on any day observed as a public fast or thanksgiving, the document may be left on the day next following any of these days (sect. 98).

month on payment of the prescribed fee. And Rule 50 of the Patents Rules, 1890, requires the application for an extension of time to state in detail in what circumstances and upon what grounds the extension is applied for. The Comptroller may require proof of the applicant's allegations.

If the complete specification is not left within due time the application will be deemed to be abandoned. The nine months will expire on that day of the ninth month which corresponds to the day of the application. Where a complete specification is left after a provisional specification the Comptroller will refer both to an examiner, for the purpose of ascertaining whether the complete specification has been prepared in the prescribed manner, and whether the invention particularly described in the complete specification is substantially the same as that described in the provisional. If the examiner reports that these conditions have not been complied with, the Comptroller may refuse to accept the complete specification unless and until the same shall have been amended to his satisfaction; but such refusal is subject to appeal to the law officer, who, if required, will hear the applicant and the Comptroller, and may make an order determining whether and subject to what conditions the complete specification shall be accepted (subsect. 3).

The fact that the complete narrows the range of the provisional specification (e.g. where the provisional specification sets forth a principle, whilst the complete only claims special mechanism) affords the Comptroller no ground of itself for refusing to accept the former. (Everitt's Case, 2 Griffin P. C. 27.)

In the opinion of two law officers, if the specification ends with a real statement of the invention claimed, distinct from the description of the invention in the body of the specification, the Patent Office has no power to inquire whether the claim is in conformity with the preceding description or not. But a claim which says no more than 'I claim the improved machine substantially as described ' would not be enough. That would be held to be merely a