INTRUSION, remedies. The name of a writ¹, brought by the owner of a fee simple, &c., against an intruder. New Nat. Br. 453.

INUNDATION². The overflow³ of waters by coming out of their bed.

2. Inundations may arise from three causes; from public necessity, as in defence of a place it may be necessary to dam the current of a stream, which will cause an inundation to the upper lands; they may be occasioned by an invincible⁴ force, as by the accidental fall of a rock in the stream; or they may result from the erections of works on the stream. In the first case, the injury caused by the inundation is to be compensated⁵ as other injuries done in war; in the second, as there was no fault of any one, the loss is to be borne by the unfortunate owner of the estate; in the last, when the riparian. proprietor⁶ is injured by such works as alter the level of the water where it enters or where it leaves the property on which they are erected⁷, the person injured may recover damages for the injury thus caused to his property by the innundation. 9 Co. 59; 4 Day's R. 244; 17 Serg. & Rawle, 383; 3 Mason's R. 172; 7 Pick. R. 198; 7 Cowen, R. 266; 1 B. & Ald. 258; 1 Rawle's R. 218; 5 N. H. Rep. 232; 9 Mass. R. 316; 4 Mason's R. 400; 1 Sim. & Stu. 203; 1 Come's R. 460. Vide Schult. Aq. R. 122; Ang. W. C. 101; 5 Ohio, R. 322, 421; and art. Dam.

TO INURE⁸. To take effect; as, the pardon inures⁹.

INVALID¹⁰. In a physical sense, it is that which is wanting force; in a figurative sense, it signifies that which has no effect.

INVASION. The entry of a country by a public enemy, making war.

2. The Constitution of the United States, art. 1, s. 8, gives power to congress "to provide for calling the militia¹¹ to execute the laws of the Union, suppress insurrections, and repel¹² invasions." Vide Insurrection.

INVENTION. A contrivance; a discovery. It is in this sense this word is used in the patent laws of the United States. 17 Pet. 228; S. C. 1 How. U. S. 202. It signifies not something which has been found ready made, but something which, in consequence of art or accident, has been formed; for the invention must relate ot some new or useful art, machine, manufacture, or composition of matter, not before known or used by others. Act of July 4, 1836, 4 Sharsw. continuation of Story's L. U.S. 2506; 1 Mason, R. 302; 4 Wash. C. C. R. 9. Vide Patent. By invention, the civilians¹³ understand the finding of some things which had not been lost; they must either have abandoned, or they must have never belonged to any one, as a pearl found on the sea shore. Lec. Elem 350.

INVENTIONES. This word is used in some ancient English charters to signify treasure-trove.

INVENTOR. One who invents or finds out something.

2. The patent laws of the United States authorize¹⁴ a patent to be issued to the original inventor; if the invention is suggested by another, he is not the inventor within the meaning of those laws; but in that case the suggestion must be of the specific process or machine; for a general theoretical suggestion, as that steam might be applied¹⁵ to the navigation of the air or water, without pointing out by what specific process or machine that could be accomplished¹⁶, would not be such a suggestion as to deprive the person to whom it had been made from being considered as the inventor. Dav. Pat. Cas. 429; 1 C. & P. 558; 1 Russ. & M. 187; 4 Taunt¹⁷. 770; B ut see 1 M. G. & S. 551; 3 Man. Gr. & Sc. 97.

3. The applicant¹⁸ for a patent must be both the first and original inventor. 4 Law Report. 342.