enrolled in Chancery within a certain time (usually one calendar month) from the date of the letters patent." The object of enforcing a full, explicit and precise disclosure of the exact invention, is to enable the public after the expiration of the patented term to "work and make" it, as the inventor alone legally could during the fourteen years. The monopoly would substantially be permanent, instead of temporary, if the patentee were at liberty to conceal either wholly or partially, or were allowed to state ambiguously the principles on which it is founded; for in many instances the corporeal substance or thing forming the subject of the patent, affords no information or clue to a discovery of the mode of making or working it. In all the cases which are before the public, in which the specification has formed the subject of discussion, we may trace the most anxious desire on the part of the Court to act fully up to this principle. A slight, though inadvertent defect, will often vitiate the grant. Few specifications have successfully stood the test of legal scrutiny: a consideration which proves the necessity of exercising the utmost circumspection and care, and of calling to the patentee's aid the skill, the experience, and the unprejudiced judgment of others. He whose mind and thoughts have long been engrossed with any given subject, overlooks the ignorance of others, and is apt to forget various matters which gradually led his mind to the discovery, and which form a part of the invention. The general rule with respect to the specification seems to be this, that it must disclose the nature of the invention, and the manner in which it is to be performed, so as to enable mechanical men of common understanding, and a reasonable degree of skill on the subject, to comprehend and make the thing by it, without any trial, experiment, invention or addition of their own (a). But it need not explain any thing. respecting the discovery so fully as to enable a person entirely ignorant of mechanics, and not conversant with the subject, to understand and act upon the specification without other assistance (b). Reference must often be necessarily made in these cases to matters of general science; or the party must (a) Bul. Nis. Pri. 76, d. Bridgm. ed. 2 Hen. Bla. 484, 496. 11 East, 107, 8. Davies on Patents, 56, 106, 128, 194, 434. 2 Barnew and Ald. 354. carry carry a reasonable knowledge of the subject-matter with him, in order clearly to comprehend specifications of this nature, though fairly intended to be made (a). In the first place the specification is insufficient if it be ambiguous, or give directions which tend to mislead the public (b). If articles are put into a specification merely to puzzle, or are not useful for the purpose of the patent, it is void (c). So where the patent was for making a particular sort of yellow, and the patentee directed any sort of fossil salt to be used; when only one sort of it would answer the purpose; the patent was held void (d). An ambiguity may arise from the specification stating as essential parts, any thing which forms a part of a prior invention; for the public are not to be deceived by the patentee holding out as material, those things which in fact are not so (e). The patentee must, in his claims to novelty, confine himself solely to that which is his invention (f). The patent must not be more extensive than the invention: and where the patent is for an improvement or addition, the patent and specification (g) must not be for the whole machine or manufacture, and the latter must describe precisely in what the alleged improvement consists; so that what is old, may be distinguishable from what is new (h). As observed by Lord Ellenborough ()," the patentee in his specification ought to inform the person who consults it, what is new, and what is old. He should say, my improvement consists in this, describing it by words if he can, or, if not, by reference to figures. But here the improvement is neither described in words nor by figures, and it would not be in the wit of man, unless he were previously acquainted with the construction of the instrument, to say what was new and what was old. The specification states, that the improved instrument is made in manner following: this is not true, since the description comprises that which is old, as well as that (a) 11 East, 113. (b) 1 T. R. 602. (c) Rex v. Ackwright, Bul. N. P. 77. Davies, 118. (d) 1 T. R. 602. (e) See Lord Ellenborough's Observations in Huddart v. Grimshaw, Davies, 279, 294, 5. (f) 11 East, 109. See per Sir Vic. Gibbs, in Bovill v. Moore, cited Davies, 398. (g) See Rex v. Ackwright, 1784, cor. Buller, Bul. Nis. Pri. 76, c. Bridgm. ed. 11 East, 109. (h) 1 Stark. 199. Davies, 411. which is new. Then it is said, that the patentee may put in aid the figures, but how can it be collected from the whole of these in what the improvement consists? 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." And if a patentee in the specification sum up the principle in which his invention consists; if this principle be not new the patent cannot be supported, although it appear that the application of the principle, as described in the specification, be new. In a late important case on this subject (a), the Court of Common Pleas held that where a person obtains a patent for a machine consisting of an entirely new combination of parts, though all the parts may have been used separately, in former machines, the specification is correct in setting out the whole as the invention of the patentee: but if a combination of a certain number of those parts have previously existed up to a certain point in former machines, the patentee merely adding other combinations, the specification should only state such improvements; though the effect produced be different throughout. But where the party obtained a patent for a new machine, and afterwards another patent for improvements in the said machine, in which the grant of the former patent was recited, it was held that a specification, containing a full description of the whole machine so improved, but not distinguishing the new improved parts, or referring to the former specification, otherwise than as the second patent recited the first, was sufficient (b). And it seems to be unnecessary in stating a specification of a patent for an improvement to designate precisely all the former known parts of the machine, and then to apply to these the improvement; 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 or such parts, describing them (c). So the falsity of any allegation in the specification will vacate the patent. As if the patentee say, that by one process he can produce three things, and he fail in any one; or if the spe (a) 2 Marshall, R. 211. (c) Ibid. 107. cification 66 cification direct the thing to be produced several ways, or by several different ingredients, and any one of them fail (a). So, if the thing could only be made with two or three ingredients specified, and the patentee has inserted others which will not answer the purpose, that will avoid the patent (b). As stated by Sir V. Gibbs, in Bovill v. Moore (c), “ another consideration respecting the specification, which is also a material one, is, whether the patentee has given a full specification of his invention, not only one that will enable a workman to construct a machine answering to the patent, but one that will enable a workman to construct a machine answerable to the patent, to the extent most beneficial within the knowledge of the patentee at the time; for a patentee who has invented a machine useful to the public, and can construct it in one way more extensive in its benefits than in another, and states in his specification only that mode which would be least beneficial, reserving to himself the more beneficial mode of practising it, although he will have so far answered the patent, as to describe in his specification a machine to which the patent extends; yet he will not have satisfied the law, by communicating to the public the most beneficial mode he was then possessed of, for exercising the privilege granted to him." As if the prosecution of a manufacture be assisted in a lace machine, by bending together two of the teeth of the dividers, or making one longer than the rest, if it appear to have been a subsequent discovery, it will not break in upon the validity of a patent, it will only shew that the patentee has since found out the means of carrying on his own invention to better effect (d); but if at the time when he obtained his patent, he was apprized of this more beneficial mode of working, and did not by his specification communicate this more beneficial mode of working to the public, that will have been a fraudulent concealment from the public, and will render the patent void (e). So, if the patentee make the article with cheaper materials than those which he has enumerated, although the latter will answer the purpose equally well, the patent is void, because he does not put the public in possession of his invention, or enable them to derive (a) 1 T. R. 602. (b) 1 Ibid. 607. (c) At N. P. Davies, 400. In C. P. 2 Marshall, 211. (d) Davies on Patents, 381. Sir V. Gibbs in Bovill v. Moore. (e) Ibid. 401. the the same benefit which he himself does (a). In a case before Lord Mansfield, for infringing a patent for steel trusses, it appeared, that the patentee in tempering the steel, rubbed it with tallow, which was of some use in the operation, and because this was omitted, the specification was held to be insufficient, and the patent was avoided (b). And in a recent case, the wilful omission to state an article, which, though it was not necessary to the composition of the manufacture, produced it more expeditiously, was held to vacate the grant (c). In short, the exact nature, and the mode of conducting the processes, and the times they are to be continued, should be accurately stated, and specifically pointed out (d). It is not necessary to set forth a model or drawing, illustrative of the invention described in the specification (e): but it is usual and perhaps advisable so to do. It should be drawn on a scale, especially where relative sizes or distances are important (f). The general rule however seems to be, that the specification must contain within itself the necessary informa tion, and should not refer to other distinct instruments or books, &c. for particulars (g). But in Harmar v. Playne (h), a patent for improvements upon a former machine was held good, although the specification described the whole machine, without distinguishing the improvements from the part of the whole machine or referring to the former specification, otherwise than as the second patent recited the first. Care must also be taken that the denomination or title of the invention in the patent is not more or less extensive, and does not vary from that mentioned in the specification. The language of the patent as was observed in a late case (i), may be explained and reduced to a certainty by the specification; but the patent should not represent the party to be the inventor of one thing, and the specification shew him to be the inventor of another; because, perhaps, if he had represented himself as the inventor of that other, it might have been well known that the thing was of no use, or was in common use, (a) 1 Term R. 607, and 1 Holt, R. N. P. 60. (b) 1 Term, 609. (c) Holt's Rep. N. P. 58. (d) 2 Barnew and Ald. 345. (e) See 2 Hen. Bla. 463. (f) Hands on Patents, 11. (g) Harmar v. Playne, 11 East, 112, S. 1 Ves. and B. 67. (h) 11 East, 101. (i) 2 Barnew and Ald. 350, 1. and |