importer, or the executor, or administrator (by appointment of a British court) of the actual inventor. The executor or administrator of any applicant can complete a patent (if, as in the former instance, appointed by a British court, otherwise he has no status). The first importer, if he have not obtained the invention by fraud from the actual inventor, is legally considered the inventor, and is entitled to all the privileges of the inventor in making application for a patent. Consequently the inventor, or any other person residing abroad, can obtain a valid patent in this country by sending it to an Agent in Great Britain, who takes it out as a communication from—(name in full and address of communicator). The patent then belongs to the individual for whom and at whose expense it was secured, whether he be the inventor or not-the Agent being only a trustee for the time being; and should the said Agent decline to make over the patent to the rightful owner, he can be compelled to do so by law.

GENERAL RULES RELATING TO BRITISH PATENTS.

1st.

Two substantial or distinct inventions cannot legally be combined in one patent. This proviso is, however, systematically evaded to a considerable extent, the practice being to consider two inventions on the same subject to be parts of the same invention. If the Law officer allows the patent to be granted, its validity cannot be afterwards questioned on the ground of its containing two or more substantially distinct inventions.

2nd. A patent gives to its owner the sole right of making, using, and selling the article or process patented, in Great Britain, Ireland, the Channel Islands, the Isle of Man, and on the adjacent seas, but not in Foreign or Colonial ships.

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3rd. It is an infringement of the patentee's rights to manufacture for one's private household use.

4th. Of two discoverers of the same invention, neither having made the matter public, the first who obtains a patent is preferred, and though a patent may be granted to both, yet the owner of the patent of earliest date has the sole right and title to the new matter common to both patents, and the second cannot use it without the first's permission.

5th. Two or more inventors effecting the same result, but by different means, can each obtain a valid patent for his mode of procedure, provided said modes are substantially different.

6th. A patent may include subject matter of another unexpired patent, but the inventor cannot of course work the previous patent without a licence from the patentee thereof.

7th.-A new application of a known thing can be patented, provided it be not analogous to any existing application thereof, or a similar material has not already been so applied. Thus, the substitution of vulcanized india-rubber for iron in the tyres of traction engines was the subject of a valid patent, while the employment of vulcanized india-rubber, then a known substance, for a purpose to which non-vulcanized rubber had been already applied, was held to be no invention, and the patent for it invalid.

8th. The new combination of two known means to effect an improved result can be patented. Thus the

hot blast and the use of anthracite had both been used separately in the smelting of iron. Yet a patent for using the hot blast in combination with anthracite was decided to be valid, the combination producing great commercial advantage.

9th. The mere omission of a part of a known process or combination, hitherto supposed to be necessary, is a valid subject for a patent, thus a patent for making tubes without a mandrel in a well-known machine in which a mandrel had always been employed

and considered necessary, was held valid. The principle on which modern courts of law lay most stress is not"Is the invention a striking one or greatly different from what has gone before?"-but "Is it productive of new and advantageous industrial results?"

10th. The possessor of an invention, specimens of which he has sold or used publicly, or exposed for sale, cannot validly patent it; nor can anyone obtain a sound patent for a process which he has already used secretly in the realm for a period of years, and sold the produce thereof.

11th. The mere experimenting on the invention before patenting, if every reasonable precaution has been taken to keep it secret, and the working has not been for profit, does not invalidate the patent afterwards obtained. Thus it was decided that the use of a steam road roller in a public street at night, previous to patenting, did not invalidate the patent, though the experiment was seen by large numbers of the publicas it was impossible to experiment on the invention in any other way than by rolling a paved road, and it was unreasonable to require the inventor to construct a special road in private grounds for the purpose. the other hand, the use of a newly-invented crane for five months in the owner's yard, which was open to the railway and to the view of customers calling on business, was held to be a publication; as five months was far more than sufficient time to test it, and the continued use was to profit, and not for the purposes of experiment.

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12th. An invention must be fully and unreservedly explained in the specification, without concealing any part, and so that any competent man, conversant with the branch of manufacture to which it is nearest related, could work it without any other instructions than those the specification affords; otherwise the patent will not be valid.

13th. Any evidence of deceit apparent on the face of the specification invalidates it; as, for instance, if an ingredient be mentioned as forming an essential part of a compound, which ingredient, however, is of no manner of use in it. Similarly, if it be found that the inventor concealed any part of his invention, or set forth an inferior mode of working, knowing of a superior one, his patent is void on the ground of bad faith.

14th. The final or complete specification must clearly distinguish and point out exactly what is new in the invention; and should anything claimed as new be proved hereafter to have been known, or in public use in the realm previous to the application, the patent becomes void. (There is an expensive remedy for this, however, as will be afterwards explained under the head "Disclaimers.")

15th. The prior existence, however, of an invention which, if it had been made subsequently to the date of the patent, would be considered a clumsy colourable imitation for the purpose of effecting the same result, does not invalidate the patent by anticipation.

16th. Similarly, a prior unsuccessful and abandoned experiment by a third party, even though it embrace all the principles of the invention, is not sufficient to invalidate the patent afterwards obtained. The imperfect publication of an invention in an abandoned provisional specification has lately been held not to invalidate a subsequent patent for the same invention.

17th. When an invention is the joint production of two minds, it must be patented in their joint names; for should it be proved that the patentee obtained material part of the invention claimed, from another individual resident in the British Isles, the patent will be invalid.

18th. Should, however, an inventor employ another individual to perform certain experiments, with a view to making a specific discovery, the discovery so made is

in the eye of the law made by the employer, and can be patented by him without using the name of the aforesaid employé, the latter being looked upon as merely an instrument employed by the inventor.

19th. An employer has no right or title to the inventions of his employés, except such as those mentioned in the previous paragraph, where the employé has been employed purposely to work out the details of a general idea unfolded to him by his employer. Even should there be a special agreement between master and servant, that all inventions of the latter made during the period of service shall become the property of the former, the patents securing said inventions must be applied for in the name of the employé.

20th. The Government does not guarantee anything in the patent, but simply gives the patentee a right to the exclusive use of his invention so long as nothing against the validity of his patent shall be proved. It is a common mistake to suppose that "a patent is a patent," and that so long as an inventor has his letters patent he has a good and sufficient title deed. It is, however, an undoubted fact that not one patent in ten as at present constituted will "hold water" (generally through defective drawing up, or from embracing what is old). This is owing in great part to the employment of "cheap agents," and it is notorious in the profession that certain individuals who send round circulars offering to take out patents at prices that cannot pay for good work, almost invariably draw up their specifications in a manner that will nullify the patent rights. Nothing indeed in the whole range of law requires so much skill to draw up as the final specification of a patent. Any ordinary lawyer can be relied on to draw up a lease or deed for the conveyance of houses or land, a bill in chancery, or a partnership agreement. There are books of precedents and rules for these that will keep him