Vis major / necessity

Although mere suspicion, not resting upon strong circumstances unexplained, should not be permitted to outweigh positive testimony in giving effect to a penal statute; yet it cannot be regarded as an oppressive rule to require of a party who has violated it to make out the vis major under which he shelters himself, so as to leave no reasonable doubt of his innocence; and if in the course of such vindication he shall pass in silence, or leave unexplained, circumstances which militate strongly against the integrity of the transaction, he cannot complain if the Court shall lay hold of those circumstances as reasons for adjudging him in delicto.