This appeal arises from convictions on four counts of delivery or possession with intent to deliver a controlled substance, namely heroin, under The Controlled Substance, Drug, Device and Cosmetic Act,1 and three counts of conspiracy.2 Appellant’s motion for a new trial and in arrest of judgment was denied by the lower court. We affirm.
The record in this case discloses the following facts. On December 1,1972, State Trooper Benjamin Brooks, a narcotics undercover agent, went to appellant’s home. Brooks was accompanied by Oscar Jenkins, an informant. Appellant transferred to Brooks a bag containing five bundles of heroin and collected $500. Later, appellant gave the money to Robert Mangini, who had provided the drugs. Appellant was permitted to retain $125 from the sale.
A second transaction occurred between Brooks and appellant on December 15, 1972, at which time Donna Jackson, a crime commission agent, and Constance Allen, Jenkins’ girlfriend, were present with Jenkins.3 Again, Brooks paid $500 for five bundles of heroin. Appellant gave the cash to Mangini.
Two further transactions, involving six bundles and two bundles respectively, occurred at the appellant’s home on January 12, and January 13, 1973. Mangini was present at the third transaction. Appellant received $100 for the final sale.
Appellant was arrested on February 20, 1973. Trial which began on October 25, 1973, resulted in a mistrial. A second trial, postponed by numerous delays and continuances, finally began on April 11, 1975. Appellant defended on the basis of entrapment, saying that he participated in these transac*83tions only because of his friendship with Oscar Jenkins. The jury nevertheless found appellant guilty on all counts. Appellant’s post-trial motions were denied and the court imposed sentence.
Appellant's first contention is that the prosecution failed to comply with a pre-trial order regarding disclosure of the informer's whereabouts. A defendant's right to disclosure of an informer is recognized in given circumstances. See, McCray v. Illinois, 386 U.S. 300, 87 S.Ct. 1056, 18 L.Ed.2d 62 (1967); Roviaro v. United States, 353 U.S. 53, 77 S.Ct. 623, 1 L.Ed.2d 639 (1957); Commonwealth v. Carter, 427 Pa. 53, 233 A.2d 284 (1967). The obligation of physically producing an informer, however, is not ordinarily imposed upon the prosecution.
Appellant maintains that the Commonwealth was instructed by pre-trial order to reveal the whereabouts of the informer, Jenkins, appellant’s admitted friend. Moreover, appellant insists that the prosecution had a duty to produce Jenkins. After a careful review of the order, we find it difficult to say what was required of the prosecution.4 The record shows, however, that the Commonwealth complied with the order to the extent of supplying appellant with known addresses of Jenkins, as well as addresses of eye-witnesses, Donna Jackson and Constance Allen.
Interpreting the pre-trial order to require only full disclosure of known whereabouts, rather than production of the informer, comports with current law, since the prosecution is not compelled to call all material eye-witnesses at trial. See Commonwealth v. Horn, 395 Pa. 585, 150 A.2d 872 (1959); Commonwealth ex rel. Sprangle v. Maroney, 423 Pa. 589, 225 A.2d 236 (1967). Moreover, in this case in which one and one half years were consumed in pre-trial delays and continuances, most of them at appellant's request, it would *84have placed an unreasonable burden on the prosecution to have required them to conduct a continuous search for the informer.
One of the most significant deficiencies in appellant’s position is that he made no pre-trial request for enforcement of the order as he now construes it. Rather, as late as January 27,1975, and February 13, 1975, appellant requested continuances so that he could locate witnesses, among them, Jenkins. At trial, appellant’s counsel conceded that the prosecution was not required to go out and find the informer or the eye-witnesses. In any event, appellant was not prejudiced, since he personally received leads as to Jenkins’ whereabouts just before trial, but failed to find his friend after reasonable efforts. Appellant located Ms. Allen, Jenkins’ girlfriend, who testified on appellant’s behalf.
Appellant's second contention is that he is entitled to dismissal of his indictments under Pa.R.Crim.P. 1100. During the interim between the mistrial and commencement of a new trial, appellant made several unsuccessful requests for dismissal under Pa.R.Crim.P. 1100(e). Then, on December 9, 1974, appellant executed a waiver of "the 270 day rule and as to speedy trial."
Appellant cites Commonwealth v. Woods, 461 Pa. 255, 336 A.2d 273 (1975), in which our supreme court held that a new trial which commenced after ninety days from the date of the grant of the new trial was in violation of Pa.R.Crim.P. 1100(e).5 We need not decide whether a second trial resulting from a mistrial is analogous to a new trial for purposes of invoking Pa.R.Crim.P. 1100(e). Regardless of who is responsible for the numerous delays in this case, appellant's unqualified waiver of his right to a speedy trial, which he executed before the court and in the presence of counsel, renders his contention meritless.
Appellant next asserts that he was subjected to double jeopardy by being required to undergo a new trial after the first resulted in a mistrial.
*85The facts underlying the mistrial are as follows. The Honorable Thomas M. Reed presided over appellant’s first trial, which commenced on October 25, 1973. Prior to completion of the first day’s testimony, Judge Reed became ill and left the bench. On October 28, 1973, defense counsel made an application for mistrial on behalf of both the Commonwealth and the appellant. Judge Blake, who was then presiding, granted the mistrial and explained that the jury would otherwise be empaneled for a minimum of ten days to two weeks awaiting the return of Judge Reed, who was then hospitalized. Unfortunately, Judge Reed subsequently died, never having returned to the bench.
The primary consideration in determining the existence of double jeopardy is a defendant's "valued right to have his trial completed by a particular tribunal." United States v. Jorn, 400 U.S. 470, 484, 91 S.Ct. 547, 557, 27 L.Ed.2d 543 (1971) (plurality opinion) (Harlan, J.). The Pennsylvania Supreme Court has held that "[d]ouble jeopardy attaches if a mistrial is declared without `manifest necessity' or without the defendant's request or consent. (citations omitted)." Commonwealth v. Wideman, 453 Pa. 119, 122, 306 A.2d 894, 895 (1973). In the instant case, appellant argues that he did not consent to a mistrial and that manifest necessity did not exist. We note first, however, that appellant did effectively consent to a mistrial. Although he did not personally request a mistrial, appellant made no objection when his counsel did so. Therefore, we conclude that counsel's request was binding on appellant. See, Commonwealth ex rel. Bell v. Rundle, 420 Pa. 127, 216 A.2d 57, cert. denied, 384 U.S. 966, 86 S.Ct. 1599, 16 L.Ed.2d 678 (1966); Commonwealth v. Nagel, 246 Pa.Super. 576, 371 A.2d 983 (1977).
The existence of manifest necessity further negates appellant's double jeopardy claim. The concept of manifest necessity was briefly detailed by Justice Story in United States v. Perez, 22 U.S. (9 Wheat.) 579, 6 L.Ed. 165 (1824):
*86“The law has invested Courts of justice with the authority to discharge a jury from giving any verdict, whenever, in their opinion, taking all the circumstances into consideration, there is manifest necessity for the act, or the ends of justice would otherwise be defeated. They are to exercise a sound discretion on the subject; and it is impossible to define all the circumstances which would render it proper to interfere. To be sure, the power ought to be used with the greatest caution, under urgent circumstances, and for very plain and obvious causes . . . ”
In Commonwealth v. Robson, 461 Pa. 615, 337 A.2d 573, cert. denied, 423 U.S. 934, 96 S.Ct. 290, 46 L.Ed.2d 265 (1975), the supreme court found manifest necessity on facts identical to those in this case, i.e., illness of the presiding judge which was expected to delay trial for two weeks or more. In such a case, a mistrial is the natural result of the "practical inability of the original tribunal to complete the trial." Id. 461 Pa. at 621, 337 A.2d at 576. Taking all of the circumstances into consideration, we find an urgent situation in which the trial court could have properly declared a mistrial sua sponte. Both manifest necessity and appellant's consent prompted mistrial, and therefore, appellant was not subject to double jeopardy.
Appellant also contends that he is entitled to a new trial or dismissal of his indictments because evidence he presented established entrapment as a matter of law. The evidence reveals that appellant told Jenkins throughout the subject transactions that he did not deal in drugs and he had no personal access to them. Appellant testified that it was only after repeated telephone calls from his. friend that he finally agreed to help Jenkins to secure drugs. Appellant further testified, however, that his prior friendship with Jenkins was marked by only one social encounter in a bar, and that there were no telephone calls and no visits by either of the men to the other’s home. Yet, it was on the strength of that friendship alone, appellant insists, that he agreed to “help” Jenkins by admittedly dealing in drugs, which he knew to be illegal. In spite of his assertion that his only motivation for *87arranging meetings and participating in sales was friendship, appellant admitted that he received $125 for the first and $100 for the last of the four drug transactions.
When considering a defense of entrapment, rather than focus on a particular defendant's readiness to commit the crime, we will look at the police conduct to determine whether there is a substantial risk that the offense would be committed by one innocently disposed. Commonwealth v. Jones, 242 Pa.Super. 303, 363 A.2d 1281 (1976). In the instant case, although Trooper Brooks knew of Jenkins' friendship with appellant, there was no evidence to establish that Brooks knew what contacts Jenkins made with appellant in his attempt to procure drugs, or the number of contacts that occurred before the first sale. There was no evidence showing that Brooks encouraged Jenkins' repeated requests in order to wear down appellant's resolve.
Courts have recognized that:
“[w]hile it is true that under normal circumstances entrapment is usually a jury question, where the evidence points to only one conclusion the question may be decided as a matter of law, just as any other factual issues admitting of only one conclusion.”
United States v. Klosterman, 248 F.2d 191, 195 (3d Cir. 1957), cited in, Commonwealth v. Mott, 234 Pa.Super. 52, 58, 334 A.2d 771, 774-75 (1975). The evidence in this case does not point clearly to only one conclusion, that of entrapment, as appellant asserts. Therefore, the trial judge was correct in presenting the issue to the jury with appropriate instructions.
Appellant next maintains that the prosecution’s failure to present evidence to establish the particular amounts of heroin sold by appellant entitles him to dismissal of the indictments or a new trial. The record shows, however, that there was evidence that appellant sold 800 packets of heroin. A defense witness estimated street value to lie between $4,800 and $12,000, while a chemist, a witness for the prosecution, estimated the value to be $10,000. We note *88that, contrary to appellant’s argument, The Controlled Substance, Drug, Device and Cosmetic Act does not designate the minimum amount of a controlled substance which must be delivered or intended to be delivered in order for criminal liability to result. Since the Commonwealth established that a substantial amount of heroin was transferred and its estimated value, we find appellant’s position meritless.
Appellant's objection to a technicality in the court's instruction on the definition of reasonable doubt is waived, since not preserved in the lower court. Commonwealth v. Clair, 458 Pa. 418, 326 A.2d 272 (1974).
Appellant submits that the trial judge improperly precluded cross-examination of Trooper Brooks concerning a December 23, 1972, transaction. There was no prior testimony regarding the incident. Although appellant contends that the evidence was integral to establishing his entrapment defense, no further evidence concerning this transaction was offered by the defense. Moreover, appellant chose not to call Brooks as his own witness, as he could have done.
The parameters of cross-examination are within the discretion of the trial judge. Commonwealth v. Donnelly, 233 Pa.Super. 396, 336 A.2d 632 (1975); Commonwealth v. Marino, 213 Pa.Super. 88, 245 A.2d 868 (1968). Here, the judge properly limited appellant's counsel to the scope of direct examination and to matters already established as relevant. Although appellant's counsel sought to make a motion at the time his cross-examination was forestalled, he acquiesced in the court's request that he postpone his motion and did not subsequently pursue it. Therefore, the court had no knowledge of appellant's hope to establish the transaction's relevance or of how he intended to do so.
Appellant’s final objection, that Brooks made a prejudicial comment when he stated that because the transaction of December 23, 1972, was not covered in the indictments he was not going to go into the matter, is totally frivolous. We note first that this claim of prejudice was not timely submitted to the lower court for consideration. *89Moreover, appellant’s counsel directed a question to that specific transaction and thereby elicited the alleged prejudicial remark.
Judgment affirmed.
HOFFMAN, J., files a dissenting opinion in which SPAETH, J., joins.. Act of April 14, 1972, P.L. 233, No. 64, § 13(a)(13) [35 P.S. § 780-113(a)(13)] as amended.
. Act of June 24, 1939, P.L. 872, § 302 (18 P.S. § 4302).
. There is conflicting testimony as to which transactions Jackson, Allen and Mangini witnessed. Apparently, however, the three were present during at least two of the sales.
. The judge originally ordered routine disclosure of the informer’s known addresses. When appellant’s counsel persisted, the judge ordered the district attorney, “if he [could] find the informant to produce him.” The judge concluded, “and, to make any reasonable efforts therein.”
. Rule 1100(e) has since been amended to permit a maximum of 120 days between the grant of a new trial and its commencement.