than this, which describes the whole combination of new and old parts, forming the entire improved machine. The patentee has only an exclusive right to the whole combination for which his patent is granted, and the use of particular parts only is no breach of his rights; the description, therefore, of the particular improvements, distinct from the parts in general use before, would be useless to all, and less intelligible to many. Patents were formerly considered as injurious monopolies, and were, therefore, construed by the Courts with great strictness; but now, when a more liberal and just view of the subject prevails, they are properly considered as highly advantageous to the public, by holding out an encouragement to ingenious men to disclose their inventions and Lord Elden, when presiding in C. B. said in the case of Cartright vs. Arnott, in Easter term, 1800, in that court, that they were to be considered as bargains between the inventors and the public, to be judged of on the principle of keeping good faith by making a fair disclosure of the invention, and to be construed as other bargains.

Lord Ellenborough, C. J.-The difficulty that presses most is, whether this mode of making the specification be not calculated to mislead a person looking at it, and induce him

to suppose that the term for which the patent is granted may extend to preclude the imitation of other parts of the machine than those for which the new patent is granted, when he can only tell by comparing it with some other patent what are the new and what are the old parts; and if this may be done by reference to one, why not by reference to many other patents, so as to render the investigation very complicated. It may not be necessary indeed, in stating a specification of a patent for an improvement, to state precisely all the former known parts of the machine, and then to apply to these the improvements; but, on many occasions, it may be sufficient to refer generally to them. As in the instance of a common watch, it may be sufficient for the patentee to say-take a common watch and add or alter such and such parts-describing them. And when Lord Mansfield said that the meaning of the specification was that others might be taught to do the thing for which the patent was granted, it must be understood to enable persons of reasonably competent skill, in such matters to make it; for no sort of specification would probably enable a ploughman, utterly ignorant of the whole art, to make a watch.

* Liardet vs. Johnson, sittings at Westminster, after Hilary, 1778, Bull. Ni. Pri. (76.)

Wetherell, contra.-The proviso in the second patent is express that the patentee shall "particularly describe and ascertain the nature of the said invention, (i e. the improvements,) and in what manner the same was to be performed," &c. if that condition be not performed, the patent is declared void. Now it is not pretended that the improvements of the machine, for which alone the second patent was granted, are particularly described and ascertained in the specification, but the whole machine, including indeed those improvements, is so described, without ascertaining the newly invented parts. But the patent was not for the whole machine, but for a part only; so that no person looking only to the second specification, or to that and the patent to which it appertained, could inform himself for what parts of the machine that patent was granted; and that knowledge can only be acquired by looking to both the patents and specifications. Unless the alteration of, or addition to, an old machine be bona fide an improvement, and useful to the public, the crown cannot grant a patent for it; and, therefore, it should appear upon the face of the instrument itself what the improvement is. Mr. Justice Buller,

** Vide Bull. N. P. (77.) pl. 4. Rule the fourth.

in the case of The King vs. Arkright,* lays down certain rules for the construction of patents, under the third and fourth of which the objections to the patent range-3dly, If the specification be in any part of it materially false or defective" the patent is void.—4thly, The patent must not be more extensive than the invention; therefore, if the invention consist in an addition or improvement only, and the patent be for the whole machine or manufacture, it is void.t" Now here the specifica

*Sitting at Westminster, after Trinity, 1785. ib.

+ For this latter is cited (among other cases, in which it was so ruled by Lord Mansfietd,) the case of the King vs. Else, sittings at Westminster Michaelmas, 1785, cor. Buller, J. The patent there was for a new invented manufacture of lace, called French, otherwise, Ground Lace. The specification went generally to the mixing of silk and cotton thread on the frame. On the part of the prosecutor it was clearly shown that prior to the patent, silk and cotton thread had been used together and intermixed upon the same frame; and the defendant's counsel acknowledged the fact; but said he could prove clearly that the former method of using the silk and cotton thread was quite inadequate to the purpose of making lace, on account of its coarseness, and that the defendant alone had invented the method of intermingling them so as to unite strength with fineness. But per Buller, J. It will be to no purpose.The patent claims the exclusive liberty of making lace composed of silk and cotton thread mixed; not of any particular mode of mixing it; and, therefore, as it has been clearly proved and admitted that silk and cotton thread were before mixed on the same frame for lace in some mode or other, the patent is clearly void, and the jury must find for the crown. Verdict accordingly.

tion is materially defective, in not ascertaining how much of the whole machine described is the new invention: and though the plaintiff has not taken out this patent for the whole machine, yet having obtained his patent for the improvement of the machine, he has not made a specification of that improvement, as he was bound by the condition of the grant to do: but has made a specification larger than the patent, upon the face of which the particular improvement cannot be ascertained. In Turner vs. Winter,* it was held that if the specification were ambiguous, or gave directions which tended to mislead the public, it avoided the patent. It is not enough, then, that persons of great skill and experience may be able to find out the invention from the specification: but it should be plainly stated, so that a person of reasonable knowledge and experience upon the subject, may immediately be made acquainted with the invention. The specification ought to inform the public what the thing is for which the patent was granted, and how it is to be made, and not merely inform them where else that information is to be acquired, for that is not a compliance with the condition. No person applying to the specification of one

* 1, Term Rep. 602.