CHADWICK V. UNITED STATES. 759 �they were alike. Eebutting evidence was given by the plain- tiffs of a clerk who testified that he, within six months after tbat, made a list of the bonds in that office, and that bis list «ontains no sucb bond; that just before the trial he made search for it in the office, and could find nothing of it, or of the letter in which it was forwarded. He also testified that there was a style of bond technically known in the depart- ment as an additional or strengthening bond, which was required and given when the one on file was not deemed suf- ficient, but that it did not supersede the old bond. Both parties resting, the defendants requested the court to instruct the jury that if the coUector filed a new bond, with new sure- ties in a like penalty, which the department acoepted, that the sureties in the old bond were discharged from that date ; but the court left it to the jury to determine whether the new bond was a substitute bond or a strengthening bond, and in- atructed them that, if it was a strengthening bond, the sure- ties were not released, telling them at the same time that, if it was a substitute bond, the views of the defendants were «orrect. Exceptions were taken, and the rulings of the court in that regard are called in question by the ninth assignment of errors. Strengthening bonds are recognized in certain acts of congress. 13 St. at Large, 225 ; 17 St. at Large, 403. Neither party exhibited any evidence to show that there is any such difference in the form or provisions of the two bonds as would enable the court to decide, as matter of law, whether the new bond was a substitute bond or a strengthen- ing bond, sometimes called an additional bond. Testimony to that effect is entirely wanting, and, in the absence of aU such testimony, it is impossible to decide that the ruling of the court, in leaving the question to the jury, is erroneous. Substitute bonds discharge sureties on the old bonds from the time the new bond is accepted. Strengthening bonds do not have that effect, as ail agree. Viewed in the light of these suggestions, it is clear that the assignment of error must be overruled. �10. Oral evidence was introduced bythe detendants sbow- ing that two of the sureties in the bond became dissatisfied, ����
