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 Ch.X. Sec.IL] Patents. 183 enrolled in Chancery within a certain time (usually one calen- dar 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 le- gally could during the fourteen years. The monopoly would sub- stantially 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 informa- tion 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 ad- dition 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 (Z>). Reference must often be necessarily made in these cases to matters of general science ; or the party must (a) Bui. Nis. Pri. 76, d. Bridgm. ed. 434. 2 Barnew and Aid. 354. 2 Hen. Bla. 484, 496. 1 1 East, 107, 8. (6) Ibid. Davies on Patents, 66, 106, 128, 194, carry