straight. This is not and cannot be the case with patent specifications, and without great care and skill on the part of the man who draws these up, they are almost certain to be valueless. It is for this reason that respectable solicitors in Great Britain invariably decline to take out patents, but refer their clients to men whose special business and training it is to draw up these documents.

21st. An invention that has been registered as a useful design, or a specimen of which has been sold in the realm, cannot be validly patented.

22nd. A British patent for an invention previously patented abroad has no real validity the moment the prior foreign patent ceases to exist.

23rd. Joint inventors obtaining a patent in their joint names, or joint owners in a patent without a special agreement, are not partners, but each has an equal and co-extensive right to work the patent to his own individual advantage.

24th. A patent can be seized by a sheriff, and in case of bankruptcy of owner, it is vested in the assignees in bankruptcy.

99 66

25th. Anyone not having a patent existing or extinct for the article in question, marking anything with the words, "Patent, Patented," "Letters Patent," or other like words, or with the trademark of any patentee, with intent to deceive or lead others to believe that it is the patented article, is liable to a fine of £50, onehalf of which goes to the patentee prosecuting.

SEARCHING.

Before applying for protection, an exhaustive search. should be made through previous patents to see if the invention be really new. Any invention can be patented, and yet, as we have already shown, the patent may be invalid owing to the invention having been previously known or patented. Three quarters of the patents taken out at

the present time are entirely worthless from this cause. This fact is well known to all patent agents; but, without special arrangements, the difficulty of making a thorough search through the 105,000 patents already enrolled is almost insurmountable. A great outlay of labour and expense is requisite to obtain the published indices and abridgments, and to make manuscript indices, &c., where those published are incomplete, and many agents discard this duty altogether, unless it be absolutely insisted on by their clients. Of course, when an exhaustive search would stop the prosecution of three out of four of the patents applied for, besides. requiring a considerable original outlay to conduct it economically and thoroughly, the temptation to unscrupulous agents to avoid this part of their duty is very great. The cost of a search varies according to the nature of the subject. A range of from two to seven guineas, however, should cover any ordinary case. Inventions for heating, for steam engines or boilers, for guns and for sewing machines, are usually the most troublesome to search through, often taking, with the ordinary published indices only, a fortnight's hard work, and even with the most complete set of additional manuscript indices, from three to seven days. In all the larger cities and towns in the British Isles complete sets of the British patent specifications, from the earliest times to the present date, are kept on file at public libraries, so that inventors may make their own searches, and should they have the requisite leisure and ability, this is decidedly the best course to pursue. Under some circumstances, however, a preliminary search is not to be recommended, especially when the invention fulfils a known want in the trade, and there is fear of being forestalled by some other applicant. When making a search, the inventor should make a record of the numbers and dates of all patents bordering on the invention, for use in drawing up the final specification.

PROVISIONAL PROTECTION.

If the result of the search prove favourable to the inventor's hopes, he should at once apply for provisional protection for six months. The services of a good patent agent are necessary here, the framing even of the title of the invention requiring skill and experience. Indeed, many good inventions have been lost to their owners through defective titles. They should neither be too general nor too restrictive. For instance, a patent for street lamps entitled "An improved method of lighting Cities, Towns, and Villages," was declared void on account of the title being too general. Another entitled "An improved Machine for giving an edge to Knives, Razors, Scissors, &c.," was declared void because it was proved not to be applicable to scissors.

The provisional specification filed at this stage, describing the invention, is kept secret by the Government till the end of six months' protection, or the completion of the patent, but can be published by the applicant should he desire to do so. The title is published in the Commissioners of Patents Journal. Provisional protection, including £5 stamp, costs, in ordinary cases, from £8 8s. to £10 10s. ($42 to $52.50c.)

The advantages secured by Provisional Protection are these:

1st. The Letters Patent afterwards obtained will date from the day when the formal application for Provisional Protection is handed in to Government. Priority is thus secured against all future applicants for letters patent for the same invention.

2nd. The inventor can from the day of application freely work, exhibit, licence, or sell his invention without thereby invalidating the letters patent afterwards obtained.

On the other hand, if an inventor does not proceed with his application, or he allow any other or others, while his invention is still only provisionally protected, to make a similar application and get ahead of him, securing the sealing of their patent first, he runs a chance of losing his rights altogether through their successful opposition, in the manner described under the head "Notice to Proceed," page 12. It is therefore always advisable,

as soon as an inventor is satisfied that his invention is worth completing, to immediately proceed with the next stages, "Notice to Proceed," and "Warrant and Seal," hereafter described.

Provisional protection does not give the right of suing infringers. Persons can indeed infringe with impunity till the third stage, hereafter described "Warrant and Seal," is passed; but the owner of a sealed patent can, even prior to the completion of the six months, and before filing his final specification, sue infringers and obtain damages for infringements of his rights, including such infringements as were made before the sealing, but after the date of the application for provisional protection.

It may here be mentioned that the applicant for letters patent, instead of a provisional protection, can, if he likes, obtain a "complete" one in the first instance. This confers, for six months, the full rights and privileges of letters patent, including the right of prosecuting infringers (not given by provisional protection). This plan is, however, not to be recommended, and is now rarely adopted. It is especially undesirable when it is intended to take out foreign letters patent, as the complete specification is immediately published; and in some countries a patentis invalid if applied for after the printed or official publication of the invention anywhere or in any language. A complete specification cannot afterwards be amended or added to; and recipients of provisional protection granted

on specifications of a wide nature, have the opportunity of including in their final specifications parts of "complete" specifications of similar inventions filed during the interim and thus of robbing the subsequent inventors of their rights. In oppositions, too, it is of great advantage to an opponent to be able to see the published complete specification of his antagonist, instead of having to fight in the dark, as in the case of a provisional specification.

The grant of provisional protection usually takes place about a fortnight after the date of application--it being dependent on the convenience of the crown law officer to whom the application is referred. Should the subject be a proper one for letters patent, and the documents be rightly drawn up, the grant is certain to be made. Owing, however, to the fact that many applications are drawn up by utterly incompetent men, about one per cent. of all applications are refused.

NOTICE TO PROCEED.

The next step in procuring letters patent may be taken immediately after the grant of provisional protection (or the filing of a complete specification), or at any subsequent time during the first four calendar months at latest after date of application. As stated previously, it is very desirable to do it as early as possible.

By the Lord Chancellor's decision ex parte Bates and Redgate, 1869, a subsequent applicant for a patent for the same invention, getting his patent sealed first, can prevent the prior applicant from obtaining a patent at all, by opposing him at this stage or at the great seal, as explained further on. Doubts have since been thrown upon this ruling, and in 1877, Lord Cairns, in ex parte Dering, gave a very nearly contrary decision. By giving notice to proceed at once the chance of opposition also is greatly lessened, and the inventor