Affidavit (Lat., he has sworn or deposed), a statement in writing, signed by the deponent and verified by his oath or affirmation made before a person authorized to take it. The affidavit is the instrument by which the action of courts is invoked in proceedings taken in the first instance ex parte, either with reference to existing actions or in special proceedings independent of such causes. Thus it is used in actions for the purpose of procuring attachments or injunctions, or in support of motions of any sort incidental to the suit in its ordinary course; or to obtain a writ of mandamus or of habeas corpus, or a warrant for the arrest of a criminal; or upon an application to oppose or vacate any of these or the like proceedings. As affidavits are in such cases ex parte, that is to say, when they are presented by the applicant for the relief, there is no final adjudication upon the matter involved until the other party interested has had an opportunity to be heard. But the sworn allegations of the first party are ordinarily sufficient to set the power of the court in motion in his favor. For the reason, too, that an affidavit is ex parte or one-sided, it is the general rule that the testimony of witnesses in causes tried in courts cannot be received in this form.

A party to an action has the right to cross-examine witnesses offered against him, and this right would be annulled by admitting affidavits against him. - No particular form of an affidavit is prescribed by our law; but in England very lately the courts have made some very expedient rules on the subject which are intended to cure some of the most frequent abuses and defects of these instruments. They require that the affidavit shall be framed in the first person, and be divided into paragraphs consecutively numbered, and each of them containing as far as possible a distinct portion of the subject. The occupation an 1 residence of the deponent must be inserted. When the paper is sworn to by an illiterate person, the jurat, or certificate of the officer who administers the oath, must state that the affidavit was read over to the party, and that he seemed to understand its contents. The jurat must also certify that the signature or mark of the deponent was made in the officer's presence. The affidavit cannot be read in court if there are any interlineations or erasures in the jurat, or if there are any in the body of the affidavit, unless they are noted with the initials of the officer. - As to the form and nature of the instrument generally: If the affidavit is made with reference to any pending action, it should be headed with the title of that action and the name of the court.

It must specify the state and county in which it is made, in order that it may appear on the face of the paper that the officer who took the oath had capacity to do so; for the power of the officer in this respect is confined to certain limits, and an oath administered outside of his jurisdiction is a nullity. Then follows the statement of facts, and this, according to a practice much followed now in New York, should be a simple narrative in the first person and confined to facts which are within the ac-tual knowledge of the deponent. Facts communicated by third persons are not proper, un-less the affidavits of those persons cannot be obtained; and in that case the sources of information should be given, and also the reason why the parties who have actual knowledge | do not themselves testify. The statement must I be signed by the deponent, or marked if he cannot write, though the omission of the signature or mark will not be fatal if the jurat shows that the affiant actually swore to the statement. The jurat is the clause which is appended by the officer taking the affidavit, in which he certifies the time when and the fact that the deponent made oath to the instrument before him. - The persons who may take affidavits are designated by law.

In England they are the judges and certain commissioners and authorized attorneys and solicitors. The authority of these last must be entered in a book kept for public reference. Conveyancers who are not attorneys or solicitors of the courts, at Westminster cannot be qualified. In the United States, judges, justices of the peace, commissioners of deeds, notaries public, and other and similar officers have authority by statute to take affidavits. All the states also appoint commissioners residing in other states and territories, and give them the same power as to such instruments to be used in the states which appoint them. The certificates of these officers are ordinarily further verified by the secretaries of state of the appointing states, who keep a record of all qualified commissioners. By recent statutes of New York (1863 and 1869), affidavits to be used there may be taken in foreign countries and in other states by any person who is authorized there to exercise a like power. Judges of the higher courts in other states are also vested by most of the states with the same powers given to their commissioners.

Generally, the authority of all foreign officials to administer oaths must be verified by some court or higher officer of the foreign state; or when a judge takes the affidavit, his signature must be authenticated by the clerk and seal of-his court. Certain officers of the United States residing abroad, the consuls at London and Paris for example, may also take affidavits, and their consular seals sufficiently authenticate their acts. British ambassadors and consuls have similar powers by | the English law. In 1802 a law was passed in New York authorizing colonels of the state regiments and certain other military officers to; take affidavits of persons in actual service out ! of the state. - An affidavit of merits is one made by a defendant which sets forth that he has stated the case to his counsel, and that he is advised by him that he has a good defence to the action upon its merits. This affidavit is required by law, in order that a defendant may not delay a plaintiffs remedy by making groundless defence to his suit; but the requirement of it does not always accomplish the designed object.