The errors enumerated by the appellant in the main appeal in each of these cases are, in substance, that the court erred in rendering “a verdict” in favor of the defendants and erred in refusing to admit testimony of a named witness. Each main appeal specifies those portions of the record to be omitted by the clerk in transmitting the record to this court. The transcript of the evidence adduced upon the trial is not specified to be omitted in either case, but no transcript has been sent to this court. Under the general presumption that public officials perform all of their duties , as required by law, it will be presumed that the clerk has transmitted to this court everything of file in his office and pertaining to these cases, except those things specified to be omitted.

The suit in each case was on a contract of guaranty, wherein *214the liability of the defendants was predicated upon a default by the principal obligor in the performance of the principal contract. Without the transcripts of the evidence it is impossible for this court to ascertain whether the plaintiff, in either case, proved its right to recover by showing a default by the principal obligor or not. Accordingly, the judgments appealed from in the main appeals will be affirmed. See Davis v. Davis, 222 Ga. 579 (151 SE2d 123).

Judgments on main appeals affirmed; cross appeals dismissed.