Correct instructions, if applicable to the case, the court, as a general rule, is required to give, unless the same are in substance and effect embodied in those previously given by the court to the jury; but the court is never required by law to give an instruction to the jury which is not applicable to the case, even though it be correct as an abstract principle or rule of law; and it may be added that no prayer for instruction, whether presented by the plaintiff or the defendant, can be regarded as applicable to the case when it is wholly unsupported by the evidence introduced to the jury. Competent evidence may be written or oral, direct or circumstantial, but when there is no legal evidence of any kind to support the theory of fact embodied in a prayer for instruction, whether presented by the plaintiff or the defendant, the instruction should slways be refused; and such a ruling can never become a good cause for reversing the judgment. It is clearly error in a court, said Taney, C. J., to charge a jury upon a supposed or conjectural state of facts, of which no evidence has been offered, as the instruction presupposes that there is some evidence before the jury which they may think sufficient to establish the fact hypothetically assumed in that way by the court, and if there is no evidence which they have a right to consider, then the charge does not aid them in coming to a correct conclusion, but its tendency is to embarrass and mislead them, as it may induce them to indulge in conjectures instead of weighing the testimony. When a prayer for instruction is presented to the court, and there is no evidence upon the subject in the case for the consideration of the jury, it ought always to be withheld, and if it is given under such circumstances, it will, as a general rule, be regarded as error in the court, for the reason that its tendency may be, and often is, to mislead the jury by withdrawing their attention from the legitimate points of inquiry involved in the issue. Bills of exceptions ought to state that evidence was offered of the facts upon which the opinion of the court is prayed, else the court is under no obligation to give the instruction. Though the judge may refuse to declare the law to the jury on a hypothetical question, yet if he gives the instruction and it is erroneous, it is the proper subject of revision. But the true rule, if there be no evidence to support the theory of fact assumed in the prayer, is to reject it, as it is error to leave a question to a jury in respect to which there is no evidence.
Attempt is made in argument to maintain that the plaintiffs had no insurable interest in the bark unless it be assumed that it was created by a bottomry bond, but the court is entirely of a different opinion, as it is alleged in the declaration that the advances were made to equip the vessel and to procure for her a cargo in the voyage from a foreign port to the port of destination. Founded as the declaration is upon the policy of insurance it must be construed in connection with the policy. By the terms of the policy the insurance is upon the bark, her tackle, and apparel, which is the proper language to be employed in a case where the insured had an interest in the vessel.