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

INUNDATION. The overflow 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 invincible 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 compensated 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. proprietor 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 erected, 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 INURE. To take effect; as, the pardon inures.

INVALID. 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 militia to execute the laws of the Union, suppress insurrections, and repel 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 civilians 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 authorize 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 applied to the navigation of the air or water, without pointing out by what specific process or machine that could be accomplished, 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 Taunt. 770; B ut see 1 M. G. & S. 551; 3 Man. Gr. & Sc. 97.

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