Defendant’s first assignment of error is that the trial court erred in allowing impeachment of defendant and defendant’s witness by reference to the week’s trial calendar on which the name of the witness appeared.
On direct examination defendant testified concerning numerous arrests and convictions resulting from violations of the liquor and motor vehicle laws. He stated that he had served time in federal prisons on three occasions, and in the State’s prisons on two occasions. He further stated: “I have never messed with dope. Naw, Sir, I have never sold anybody any dope.”
On cross-examination the Solicitor, without objection, read from the trial calendar numerous names of persons charged with violating narcotic laws, and questioned defendant concerning his acquaintance and association with each of them. One typical example of these exchanges is as follows:
*595Q. . . . Now, you know a young man “Tramp”?
A. Yes sir.
Q. What is his real name ?
A. I don’t know.
Q. Harry Gulledge, that sound familiar to you?
A. Naw.
Q. How far does he live from you ?
A. About a block.
Q. Right down the way from you, right down a little old dirt path, isn’t it, right on down from your house?
A. Oh, you can go down it.
Q. —right on down through the dirt path ?
A. Uh huh.
Q. And how old is Tramp ?
A. I don’t know.
Q. He is about 21 or so, isn’t he?
A. I don’t know. I guess so, looks like he might have been like that.
Q. All these folks live right around you, right within a block of you, don’t they?
A. That is right.
Q. Of course, you are aware that all of them too have been arrested this year for selling heroin, aren’t you?
A. Yes sir.
Throughout this interrogation defendant did not admit that any of these persons worked for him or were associated with him in the handling of narcotics.
Defendant further stated that his means of livelihood for the past twelve months had been gambling. He admitted that several automobiles which he drove, and which were titled in other persons’ names, belonged to him. It was only after the *596Solicitor began to examine defendant as to Ms income tax that his counsel interposed objection. This objection was sustained, and thereafter defendant’s counsel requested that the jury be excused. Defendant’s counsel, in the absence of the jury, made a motion for mistrial based on the questions directed to defendant’s having a retained lawyer and to defendant’s income tax. The motion was denied.
[1, 2] Defendant’s assignments of error are not in accord with our rules and decisions, in that they do not set out within the assignment the evidence which he contends should not have been admitted. North Carolina Supreme Court Rules of Practice 19(3); State v. Fox, 277 N.C. 1, 175 S.E. 2d 561; S. v. Kirby, 276 N.C. 123, 171 S.E. 2d 416. Furthermore, defendant failed to object to the questions relating to the trial calendar and thereby waived his objections. State v. Blackwell, 276 N.C. 714, 174 S.E. 2d 534; State v. Sanders, 276 N.C. 598, 174 S.E. 2d 489. However, we do not choose to dispose of this assignment of error because of failure to observe the rules of this Court.
[3-5] A Solicitor may ask a defendant or his witness questions tending to discredit their testimony, no matter how disparaging the question may be. Nevertheless, the Solicitor may not needlessly badger or humiliate such witnesses by asking insulting and impertinent questions which he knows will not elicit competent or relevant evidence. State v. Wyatt, 254 N.C. 220, 118 S.E. 2d 420; State v. Phillips, 240 N.C. 516, 82 S.E. 2d 762. It is well recognized, however, that the trial judge, who sees and hears the witnesses and knows the background of the case, has a wide discretion in controlling the scope of cross-examination. State v. McPherson, 276 N.C. 482, 172 S.E. 2d 50; State v. Ross, 275 N.C. 550, 169 S.E. 2d 875. Likewise, a motion for mistrial in cases less than capital is addressed to the trial judge’s sound discretion, and his ruling thereon (without findings of fact) is not reviewable without a showing of gross abuse of discretion. State v. Battle, 267 N.C. 513, 148 S.E. 2d 599; State v. Pfeifer, 266 N.C. 790, 147 S.E. 2d 190; State v. Birckhead, 256 N.C. 494, 124 S.E. 2d 838.
[6] We are unable, from the cold record, to determine the impact upon the jury of the questions directed to defendant concerning people whose names appeared on the trial calendar. Its force is made very questionable by the very fact that it did not stir the defendant’s experienced trial lawyer to interpose ob*597jection. In light of defendant’s past record, defendant’s answers and the State’s compelling eyewitness testimony, we do not think that the evidence towards which this assignment of error was aimed was so material and prejudicial to defendant’s rights that a different result would have likely ensued. State v. Swaney, 277 N.C. 602, 178 S.E. 2d 399; State v. Brinson, 277 N.C. 286, 177 S.E. 2d 398; State v. Sanders, supra. Certainly, this record does not disclose that the trial judge’s ruling or failure to act ex mero motu constituted an abuse of his discretion.
For reasons stated, this assignment of error is overruled.
[7] Defendant next contends that the impeachment of defendant and his only witness by questions showing prior arrests and indictments for criminal offenses by each of them, constituted prejudicial error.
In this connection we note that defendant abandoned this assignment of error in the Court of Appeals in light of the weight of authority contrary to his contention. However, on 15 December 1971 this Court handed down the opinion in the case of State v. Williams, 279 N.C. 663, 185 S.E. 2d 174, which, inter alia, states:
“We now hold that, for purposes of impeachment, a witness, including the defendant in a criminal case, may not be cross-examined as to whether he has been indicted or is under indictment for a criminal offense other than that for which he is then on trial. In respect of this point, we overrule State v. Maslin, supra [195 N.C. 537, 143 S.E. 3], and decisions in accord with Maslin, on the basic ground that an indictment cannot rightly be considered as more than an unproved accusation.”
Defendant, relying on the holding in State v. Williams, supra, petitioned this Court for certiorari, and this Court allowed certiorari. The Court in Williams did not decide whether its holding would be applied retroactively. However, in State v. Harris, (filed this day) this Court determined that the holding in Williams should be applied prospectively only. The Court noted that the change accomplished in Williams affected only a rule of evidence, and did not affect a contractual or a vested right. In reaching the conclusion that the decision in Williams *598should be applied prospectively, Moore, J., speaking for the Court, stated:
“ To give Williams retroactive effect could easily disrupt the orderly administration of our criminal law. Doubt would be cast upon verdicts of guilty returned in those cases where such questions were asked and answered over objection. Prisoners convicted in such trials could seek release or new trials in post-conviction proceedings. See Johnson v. New Jersey, 384 U.S. at 731, 16 L.Ed. 2d at 891, 85 S.Ct. at 1780 (1966). Accordingly, we hold that the rule announced in Williams applies only to those trials begun after 15 December 1971, the date of the filing of the opinion in that case....”
Here, the trial commenced on 14 April 1971. State v. Williams, supra, does not apply, and this assignment of error is overruled.
The decision of the Court of Appeals is
Affirmed.