oath that the foregoing deposition by him subscribed contains the truth, the whole truth, and nothing but the truth. The said deposition is taken at the request of Lyman Osgood, to be used upon the hearing of an interference between the claims of the said Lyman Osgood and those of Charles Comstock, before the Commissioner of Patents, on the 3d day of May, A. D. 1869.

The said Charles Comstock was duly notified, as appears by the original notice hereto annexed, and attended by Charles Cavil, esq., his counsel. SEXTUS TARQUIN, Justice of the Peace.

The magistrate shall seal up the testimony, and write upon the envelope a short certificate, substantially in the following form, viz:

I hereby certify that the within depositions of Truman Truthful and Peter Pivot, relating to the matter of interference between Lyman Osgood and Charles Comstock, were taken, sealed up, and addressed to the Commissioner of Patents by me this 26th day of April, A. D. 1869.

343. PRESUMPTION.-The general head of presumptive evidence is usually divided into two branches, namely, presumptions of law and presumptions of fact. Presumptions of law consist of those rules which, in certain cases, either forbid or dispense with any ulterior inquiry. They are founded either upon the first princi

ples of justice, or the laws of nature, or the experienced course of human conduct and affairs, and the connection usually found to exist between certain things. The general doctrines of presumptive evidence are not therefore peculiar to municipal law, but are shared by it in common with other departments of science. Thus, the presumption of a malicious attempt to kill from the deliberate use of a deadly weapon, and the presumption of aquatic habits in an animal found with webbed feet, belong to the same philosophy, differing only in the instance, and not in the principle, of its application. The one fact being proved or ascertained, the other, its uniform concomitant, is universally and safely presumed. It is this uniformly experienced connection which leads to its recognition by the law without other proof; the presumption, however, having more or less force in proportion to the universality of the experience. And this has led to the distribution of presumptions of law into two classes, namely, conclusive and disputable. (Greenleaf on Evidence, p. 21.)

Conclusive, or, as they are elsewhere termed, imperative or absolute, presumptions of law, are rules determining the quantity of evidence requisite for the support of any particular averment, which is not permitted to be overcome by any proof that the fact is otherwise. They consist chiefly of those cases in which the long-experienced connection before alluded to has been found so general and uniform, as to render it expedient for the common good that this connection should be taken to be inseparable and universal. They have been adopted by common consent, from motives of public policy, for the sake of greater certainty, and the promotion of peace

and quiet in the community; and therefore it is that all corroborating evidence is dispensed with, and all opposing evidence is forbidden. (Ib.)

The second class of presumptions of law, answering to the præsumptiones juris of the Roman law, which may always be overcome by opposing proof, consists of those termed disputable presumptions. These, as well as the former, are the result of the general experience of a connection between certain facts or things, the one being usually found to be the companion or the effect of the other. The connection, however, in this class, is not so intimate or so universal as to render it expedient that it should be absolutely and imperatively presumed to exist in every case, all evidence to the contrary being rejected; but yet it is so general, and so nearly universal, that the law itself, without the aid of a jury, infers the one fact from the proved existence of the other, in the absence of all opposing evidence. In this mode the law defines the nature and amount of the evidence which it deems sufficient to establish a prima facie case, and to throw the burden of proof on the other party; and if no opposing evidence is offered, the jury are bound to find in favor of the presumption. A contrary verdict would be liable to be set aside, as being against evidence. (Ib., p. 38.)

Presumptions of fact, usually treated as composing the second general head of presumptive evidence, can hardly be said, with propriety, to belong to this branch of the law. They are, in truth, but mere arguments, of which the major premise is not a rule of law; they belong equally to any and every subject-matter; and are to be judged by the common and received tests of the truth

of propositions and the validity of arguments. They depend upon their own natural force and efficacy in generating belief or conviction in the mind, as derived from those connections which are shown by experience, irrespective of any legal relations. They differ from presumptions of law in this essential respect, that while those are reduced to fixed rules, and constitute a branch of the particular system of jurisprudence to which they belong, these merely natural presumptions are derived wholly and directly from the circumstances of the particular case, by means of the common experience of mankind, without the aid or control of any rules of law whatever. Such, for example, is the inference of guilt drawn from the discovery of a broken knife in the pocket of a prisoner, the other part of the blade being found sticking in the window of a house which, by means of such an instrument, had been burglariously entered. These presumptions remain the same in their nature and operation, under whatever code the legal effect or quality of the facts, when found, is to be decided. (Ib., p. 49.)

It is a presumption of law, that when a patent has been obtained, and the specification and drawing recorded in the Patent Office, every man who subsequently takes out a patent for a similar machine has a knowledge of the preceding patent. As in chancery it is a maxim that every man is presumed to have notice of any fact upon which he is put upon inquiry by documents within his possession, if such facts could, by ordinary diligence, be discovered upon such inquiry. It is also a presumption of fact that every man, having within his power the exact means of information, and desirous of securing to himself the benefit of a patent, will ascertain, for his own

interest, whether any one on the public records has acquired a prior right. (Odiorne v. Winkley, 2 Gall., 55.) All persons are bound to take knowledge of the doings of the Patent Office in relation to inventions. (Marcy v. Trotter, MS. Appeal Cases, D. C., 1860.)

In the case of the Philadelphia and Trenton Railroad Company v. Stimson, (14 Peters, 458,) Mr. Justice Story said: "It is a presumption of law that all public officers perform their proper official duties until the contrary is proved. And where, as in the present case, an act is to be done, or patent granted upon evidence and proofs to be laid before a public officer, upon which he is to decide, the fact that he has done the act or granted the patent is prima facie evidence that the proofs have been regularly made, and were satisfactory. No other tribunal is at liberty to reexamine or controvert the sufficiency of such proofs, if laid before him, when the law has made such officer the proper judge of their sufficiency and competency. It is not, then, necessary for the patent to contain any recitals that the prerequisites to the grant of it have been duly complied with, for the law makes the presumption; and if, indeed, it were otherwise, the recitals would not help the case, without the auxiliary proof that these prerequisites had been, de facto, complied with. This has been the uniform construction, as far as we know, in all our courts of justice upon matters of this sort. Patents for lands, equally with patents for inventions, have been deemed prima facie evidence that they were regularly granted, whenever they have been produced under the great seal of the government, without any recitals or proofs that the prerequisites of the acts under which they have been issued have been duly