We granted rehearing en banc to decide whether a district court may, in a criminal prosecution for interstate transportation of a falsely made security, instruct the jury that a particular document is a security as a matter of law. We hold that, although it is the court’s duty to instruct the jury on the legal principles applicable to the determination of that question, it is the jury’s exclusive province to apply the law to the facts and determine whether the document is a security. Accordingly, we reverse the defendant’s conviction for violating 18 U.S.C. § 2314 (1976). We affirm his conviction for violating 18 U.S.C. § 1343 (1976) because that charge did not require proof that the document was a security.
I.
In 1977 William J. Johnson, the defendant, joined in promoting the formation of a California corporation, International Vaults, Ltd. (International), to engage in trading gold and other precious metals. Johnson left the company in 1978 because he was having marital difficulties. Thereafter, between April and November 1980, International offered investors “promissory certificates,” advertising a return of 8 percent monthly. It planned to use the funds raised to buy gold directly from Alaskan miners for resale in the commercial market, hoping that it could buy and sell rapidly enough to net revenues sufficient both to pay investors the grand return it promised them and to make a profit. The certificates were not registered as securities with the state or federal government.
In mid-November 1980, International stopped selling the certificates because its attorney advised the company that it might be violating federal securities law. The lawyer advised International to undertake a public stock offering, which required the company to prepare a certified financial statement. International’s officers, therefore, hired an accountant and an independent auditor to verify the company’s assets. At that time or soon thereafter, the California Department of Corporations asked International to suspend operations pending an investigation of the corporation’s compliance with state securities laws.
One of the corporation’s major assets was an unpaid promissory note for $8 million made by its agent, Eastman, who had been buying the Alaskan gold. Because Eastman could not be located, the verification process fell behind schedule and management’s concern about the Department of Corporations’ investigation heightened. They hired Johnson to verify the company’s assets, satisfy state officials, and enable International to resume business.
Johnson’s first mission was to obtain an asset worth $8 million to substantiate International’s net worth while it sought payment from Eastman on the promissory note. To this end, he travelled to Dallas to meet with William Brinlee, an acquaintance who dabbled in investments. Brinlee supplied Johnson with a document titled “Gold Certificate Contract,” the full text of which is set forth in the margin, purporting to instruct that 17,000 ounces of gold held in a bonded warehouse be delivered to “Int. Vaults, Ltd./William J. Johnson.”1
*1319The original document did not state the price to be paid for the gold on delivery. Brinlee retained a duplicate on which Johnson had written: “To be paid in cash upon delivery of Gold.” Johnson allegedly promised Brinlee that he would return the original certificate within three days and pay $75,000 for its use during that period.
Johnson travelled by plane from Dallas to California with the document. International’s officers immediately presented it to the auditors, representing that the $8 million promissory note had been “retired” and that the Gold Certificate confirmed the existence of a corporate asset in that amount. The auditors attempted to verify the value of the certificate and, in the process, made telephone calls to Dallas. They were, however, unable to verify the existence of the gold the certificate represented, so they could not complete the audit.
Johnson, concerned at the suggestion that the certificate was “no good,” returned to Dallas. He met with Brinlee and returned to California with a “bill of sale” for one million tons of coal. The auditors again made inquiries but could not verify the value of this asset. In short order, International declared bankruptcy.
The federal government then charged Johnson with two counts of fraud. Count One alleged that Johnson “knowingly, wilfully and with unlawful and fraudulent intent, did transport and cause to be transported in interstate commerce ... a falsely made security, that is, a gold certificate contract ... knowing such security to be falsely made. A violation of [18 U.S.C. §] 2314.” Count Two charged that Johnson: “for the purpose of executing [a] scheme [to defraud by means of false and fraudulent pretenses] .. . knowingly and willfully caused to be transmitted in interstate commerce, wire signals, to wit: a long distance telephone conversation.... A violation of [18 U.S.C. §] 1343.”
One of Johnson’s defenses to Count One was that the Gold Certificate Contract was not a security. The district judge instructed the jury that the prosecution had to prove as an essential element of the offense that Johnson carried a falsely made security in interstate commerce. However, he refused to submit to the jurors the question whether the Gold Certificate was such a security, instructing them that the certificate was a security as a matter of law.2
*1320The jury found Johnson guilty on both counts. The judge sentenced him to serve thirty months on the interstate transportation count and five years’ probation on the wire signal count.
The panel opinion affirmed the judgment of conviction. 700 F.2d 168 (5th Cir.1983), reh’g granted, 700 F.2d at 181 (5th Cir.1983) (en banc).
II.
By the time the Constitution was drafted, the institution of trial by jury in criminal cases had been in existence in England for several centuries.3 It was guaranteed in the constitutions of each of the original thirteen states,4 and was considered “ ‘part of that admirable common law which had fenced around and interposed barriers on every side against the approaches of arbitrary power.’ ”5 The body of the Constitution itself commands that “the Trial of all Crimes, except in Cases of Impeachment, shall be by Jury.” U.S. Const, art. Ill, § 2. The sixth amendment elaborates this assurance, guaranteeing the accused in all criminal prosecutions the right to a speedy and public trial by an impartial jury. These provisions “reflect a fundamental decision about the exercise of official power — a reluctance to entrust plenary powers over the life and liberty of the citizen to one judge or to a group of judges.” Duncan v. Louisiana, 391 U.S. 145, 156, 88 S.Ct. 1444, 1451, 20 L.Ed.2d 491, 500 (1968).
The sixth amendment guarantees “a trial by jury as understood and applied at common law, and includes all the essential elements as they were recognized in this country and England when the Constitution was adopted....”6 The test is not entirely historical, for our inquiries “must focus upon the function served by the jury in contemporary society.”7
The fifth and fourteenth amendment guarantees of due process of law afford further guarantees to the accused. The due process clause “protects the accused against conviction except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged.”8 This means that the prosecution must prove beyond a reasonable doubt the defendant’s guilt of “ev*1321ery element of the charged offense.”9 Therefore, “a judge may not direct a verdict of guilty no matter how conclusive the evidence.” Connecticut v. Johnson, - U.S. -, -, 103 S.Ct. 969, 976, 74 L.Ed.2d 823, 832 (1983) (plurality opinion) (quoting United Brotherhood of Carpenters & Joiners v. United States, 330 U.S. 395, 408, 67 S.Ct. 775, 782, 91 L.Ed. 973, 985 (1947)). The plurality opinion in Connecticut v. Johnson, rendered only months ago, reiterated the Court’s “consistent” holding that a trial judge is prohibited from directing the jury to come forward with a verdict of conviction. Johnson,-U.S. at-, 103 S.Ct. at 976, 74 L.Ed.2d at 832 (plurality opinion).
III.
The government argues that the judge in this case acted properly because the trial judge decides “questions of law” while the jury decides only “questions of fact.”10 This distinction is at best elusive.11 There is no categorical distinction between “legal” and “factual” questions, for in every case application of a legal principle turns on the presence of particular facts.12 A contemporary author has aptly explained why the “law” and “fact” distinction misses the mark in criminal trials.
There is considerable misunderstanding in the minds of the general public regarding provisions making a jury the judge of fact and not of law. This misunderstanding is attributable in large part to the inaccuracy of the general rule that juries decide only the facts. This is an inaccurate expression because it leaves the -impression that juries are not judges of the law at any time or in any sense. Juries are always judges of the law in the sense that juries must pass on the manner and the extent in which the law expounded by the judge fits the facts brought out in the evidence. This process requires juries to perform the legal function of interpretation and application. In the absence of express authority, however, juries are not judges of the law in determining what principle of law is applicable to the evidence.
S. McCart, Trial by Jury 116-17 (1965) (emphasis in original). Hence, although attempting to separate “fact” from “law” may sometimes be useful, particularly when a statute or a federal rule turns on the differentiation, it is not the issue here. The issue is the role of the jury in the trial guaranteed to the accused.13
*1322This difference in function between judge and jury has been long established. In the first jury trial conducted in the United States Supreme Court, Chief Justice Jay, after stating that the facts were undisputed and giving the Court’s unanimous opinion about the law, nevertheless reminded the jurors:
[O]n questions of fact, it is the province of the jury, on questions of law, it is the province of the court, to decide. But it must be observed, that by the same law, which recognizes this reasonable distribution of jurisdiction, you have, nevertheless, a right to take upon yourselves to judge of both, and to determine the law as well as the fact in controversy.
Georgia v. Brailsford, 3 U.S. (3 Dall.) 1, 4, 1 L.Ed. 483, 484 (1794) (footnotes omitted) (civil case).
In 1835, Justice Story, sitting on circuit, affirmed that principle. Although he instructed that the jury “are no more judges of the law in a capital or other criminal case, upon the plea of not guilty, than they are in every civil case,” he added, “In each of these cases, their verdict, when general, is necessarily compounded of law and of fact; and includes both. In each they must necessarily determine the law, as well as the fact.” United States v. Battiste, 24 Fed. Cas. 1042, 1043 (C.C.D.Mass.1835) (No. 14,-545).
Thus the jury may not be relegated to deciding only questions that the judge thinks to be “factual”. Federal judges instruct the jury on the law applicable to the issues raised at trial. Fed.R.Crim.P. 30 permits any party to ask that the court “instruct the jury on the law as set forth in [written] requests.” But the judge’s role is simply to instruct the jury “on the law.” Except in the rare case when, perhaps, a jury may still be instructed to return a special verdict,14 the jury in a criminal trial does not answer interrogatories and it does not “find” facts.15 It decides whether the defendant is guilty or not guilty.
IV.
We have previously held that the judge may not decide whether a particular piece of paper purporting to be a contract is a security but must submit that issue to the jury. In Roe v. United States, 287 F.2d 435 (5th Cir.), cert. denied, 368 U.S. 824, 82 S.Ct. 43, 7 L.Ed.2d 29 (1961), the defendant was charged with illegal sale and delivery of unregistered securities based on his selling mineral leases. See 15 U.S.C. § 77e(a)(1), (2) (1976). We held that the determination whether the particular documents described as “mineral leases” were securities was for the jury, saying:
More than that, this being a criminal case ... no fact, not even an undisputed fact, may be determined by the Judge. The plea of not guilty puts all in issue, even the most patent truths. In our federal system, the Trial Court may never instruct a verdict either in whole or in part. And yet, that is substantially what the Trial Judge did here on the crucial issue of whether these were investment contracts. He instructed them flatly and without equivocation that they were.
287 F.2d at 440 (citations and footnotes omitted). Other intermediate appellate decisions interpreting the jury’s province do not, of course, speak with one voice. Some decisions support the conclusion we now reach.16 Others support the contrary posi*1323tion.17 Discord in the precedents provides all the more reason to look to principle. And the fundamental and “elementary”18 principles involved in this case are that the government must prove every element of the crime beyond a reasonable doubt and that, in criminal cases, the court simply may not direct a verdict on any issue.
The essential elements of the crime Johnson was accused of in Count One are that he (1) transported in interstate commerce (2) a security (3) that was falsely made (4) knowing that it was falsely made (5) with Unlawful or fraudulent intent. See 18 U.S.C. § 2314. The district judge was no more entitled to refuse to allow the jury to decide whether the Gold Certificate was a security than he would have been permitted to refuse to charge on whether the Certificate was falsely made or whether Johnson acted knowingly. Knowledge that the Gold Certificate was false or forged was, of course, also an essential element of the crime. But submission of this element to the jury does not excuse the failure to submit a different element: whether, regardless of Johnson’s subjective belief or knowledge, the Gold Certificate was a security.
The Certificate purports to be a promise to deliver 17,000 troy ounces — a quantity equivalent to 1,411 troy pounds — of 999.5 fine gold for an unspecified price. It states expressly that it is neither negotiable nor usable as collateral. The jurors might have decided that this self-laudatory document was literally not worth the paper on which it was printed and was not a security at all.19 They were not permitted to do that, however, because the judge told them that the certificate was a security and also instructed them: “You have no right to disregard or to give special attention to any one instruction, or to question the wisdom or the correctness of any rule that I may state to you. That is, you must not substitute or follow your own notion or opinion as to what the law is or ought to be.” (emphasis added).
To the principle that the judge must submit every essential element of the offense to the jury there are two historical exceptions. Over a half a century ago, the Supreme Court held that a defendant indicted for contempt of Congress by refusing to answer questions put to him was not entitled to have the jury decide whether the questions were pertinent to any inquiry the congressional committee was authorized to make. “The question of pertinency,” the Court said in Sinclair v. United States, 279 *1324U.S. 263, 298, 49 S.Ct. 268, 273, 73 L.Ed. 692, 700 (1929), “was rightly decided by the [district] court as one of law. It did not depend on the probative value of evidence. That question may be likened to those concerning relevancy at the trial of issues in court, and it is not essentially different from the question as to materiality of false testimony charged as perjury in prosecutions for that crime.”
Despite the Supreme Court’s statement that “[t]he reasons for holding relevancy and materiality to be questions of law ... apply with equal force to the determination of pertinency .... ” id. at 299, 49 S.Ct. at 273, 73 L.Ed. at 700, the comparability of a ruling on the admissibility of evidence, which is the sole question when relevancy is examined, and determining an issue upon which guilt or innocence depends is not immediately obvious to us. We are, therefore, reluctant to expand Sinclair’s sweep at the expense of the accused’s right to interpose the jury between himself and the judge.
Moreover, there is a distinction between deciding pertinency and materiality and deciding whether a tangible document or thing meets a statutory definition. The former inquiry turns primarily on reason. The latter depends upon the probative value of evidence even when the evidence seems so clear as to leave no room for fool’s questions. Thus it is a jury question whether the prosecution has proved that a pistol introduced in evidence is a firearm or that an automobile identified by a witness is a motor vehicle even though few would seriously debate the contrary. Similarly, it cannot be determined whether something called a Gold Certificate is a security without some evidence: the introduction of the document and testimony about the significance of its contents. Indeed the parties offered and the court admitted conflicting testimony of expert witnesses concerning the nature of the document.
For these reasons, both historical and functional, we do not by this opinion erode either the ruling in Sinclair or our many decisions that follow its dicta by holding that the materiality of false statements is a question for the court.20 We merely refuse to extend the exception Sinclair recognized.
V.
The judge’s duty to instruct the jury and to submit to it the determination of guilt or innocence does not deprive him of his common-law power to comment on the evidence. We have consistently held that it is not error for judges to guide jurors in their deliberations by remarking on the evidence. *1325But we have made clear that, “if the trial judge chooses to comment on the evidence, he must instruct the jury that they are not bound by his comments.21 In fact, the trial judge in this case did comment on the evidence, summarizing the various documents for the jury at the conclusion of one witness’s testimony and then instructing the jurors: “[I]f the documents don’t support ... my summary, disregard it.” The judge must stop with commentary. He may not go so far in his remarks as to seriously prejudice the defendant22
The jury’s function is “the independent determination of the facts, and the application of the law ... to the facts .... ” 2 C. Wright, Federal Practice and Procedure § 485, at 711 (2d ed. 1982) (emphasis added). Therefore, the jury charge should be a statement of the parties’ claims, “the issues of fact that the jury must decide, and the applicable law____” Id. (emphasis added). “Put simply, the right to be tried by a jury of one’s peers finally exacted from the king would be meaningless if the king’s judges could call the turn.” United States v. Spock, 416 F.2d 165, 181 (1st Cir.1969) (footnote omitted). Johnson’s judge called the turn; he became Johnson’s jury on an essential element of the crime charged. He did not confine himself to instructing the jury about applicable legal principles or commenting on the evidence. He usurped the jury’s province and applied the law to the facts as he understood them. What the state is barred from taking from the jury by autocratic command, its judges may not themselves arrogate.
The judgment of the district court entered on Count One is REVERSED and the. case is REMANDED for a new trial on that Count.23
. The document read:
GOLD CERTIFICATE CONTRACT
******
Deliver to: Int. Vaults, Ltd/Wm. J. Johnson only — 17,000 — seventeen thousand — TROY OUNCES of GOLD on demand after — 360— DAYS from the date hereon.
[Signed] R.C. Massner I.M.F. Systems, Inc.
-CONDITIONS-
*13191. GOLD shall be dleivered [sic] in bars of one thousand Trou [sic] ounces, plus or minus five (5) percent and shall be 999.5 fine GOLD or better.
2. Delivery shall be made to any bank or bonded warehouse in Dallas, Texas, for the account of the purchaser.
3. No interest shall be paid on this certificate.
4. This certificate can be transferred only on the books of I.M.F. Systems, Inc. by written authorization of I.M.F. Systems, Inc. to the Transfer Agent. This certificate cannot be divided or sold in fractional shares.
5. This certificate shall be redeemable in GOLD as specified in paragraph one, and the purchaser acquires no right or rights to any ore, mines, mineral deposits, smelters, processes, formulas, trade secrets, or operations, of any nature belonging to I.M.F. Systems, Inc. and I.M.F. Systems Inc. shall not be obligated to deliver GOLD from any particular mine, or refined by any specific process.
6. This certificate shall not be sold, transferred, traded, or assigned as collateral.
7. Purchaser agrees that this certificate shall be for his own investment account and not for resale.
8. Owner shall surrender this certificate on or after the due date and sign a receipt for the amount specified herein. Delivery before the due date shall be at the option of I.M.F. Systems, Inc.
9. This certificate is backed by an original Bill of Sale and an original assigment [sic] of interest in a bonded warehouse receipt. These documents are on deposit with Security Trust Company of Dallas, Texas and shall be held by The Trust Company until this certificate is redeemed by delivery of the GOLD.
The Certificate was signed by Roy Massner, a founder of I.M.F. Systems, Inc., and by Johnson.
. “You are instructed that the gold certificate contracts in this case are securities under the meaning of Title 18, United States Code, Section 2318.” After the jury retired, Johnson’s lawyer objected to the charge:
MR. HOFFMAN: Your Honor, we object to the instructions to the Jury that the gold certificate contract is a security.
[THE COURT]: As I understand, your objection to the Charge is the court has instructed *1320the Jury that the gold contract in question is, in fact, a security and it’s your contention that this is an issue of fact. Well, first your contention is that it is not a security as a matter of law.
MR. HOFFMAN: Yes, sir.
THE COURT: And that’s one of the bases for your Judgment of Acquittal. Secondly, it’s your contention and your objection to the Charge that at least it’s a question of fact that the Jury should determine.
MR. HOFFMAN: Yes, sir.
THE COURT: And that the Jury should be instructed on a definition of a security and it should be left up to the Jury; is that correct? MR. HOFFMAN: Yes, sir, that is our position.
THE COURT: I think it’s clear from the record that that is what your position is. Is that all?
MR. HOFFMAN: Yes, sir.
THE COURT: All right, I’ll overrule your objection and note your exception.
. See Duncan v. Louisiana, 391 U.S. 145, 151, 88 S.Ct. 1444, 1448, 20 L.Ed.2d 491, 497 (1968).
. Id. at 153, 88 S.Ct. at 1449, 20 L.Ed.2d at 498.
. Thompson v. Utah, 170 U.S. 343, 349-350, 18 S.Ct. 620, 622, 42 L.Ed. 1061, 1066 (1898), (quoting 2 J. Story, Commentaries on the Constitution of the United States § 1779 (1833)).
. Patton v. United States, 281 U.S. 276, 288, 50 S.Ct. 253, 254, 74 L.Ed. 854, 858 (1930).
. Apodaca v. Oregon, 406 U.S. 404, 410, 92 S.Ct. 1628, 1632, 32 L.Ed.2d 184, 191 (1972) (plurality opinion). Thus, for example, neither a jury of twelve, Williams v. Florida, 399 U.S. 78, 90 S.Ct. 1893, 26 L.Ed.2d 446 (1970) (six-member jury constitutional); see Ballew v. Georgia, 435 U.S. 223, 98 S.Ct. 1029, 55 L.Ed.2d 234 (1978) (five-member jury unconstitutional); nor unanimity of verdict, Apodaca v. Oregon, 406 U.S. 404, 92 S.Ct. 1628, 32 L.Ed.2d 184 (1972); is essential, but the jury must be selected from a representative cross-section of the community. Taylor v. Louisiana, 419 U.S. 522, 527-28, 95 S.Ct. 692, 696, 42 L.Ed.2d 690, 696-97 (1975) (exclusion of women who do not file written declaration of willingness to serve unconstitutional).
. In re Winship, 397 U.S. 358, 364, 90 S.Ct. 1068, 1073, 25 L.Ed.2d 368, 375 (1970).
. Moore v. United States, 429 U.S. 20, 22, 97 S.Ct. 29, 30, 50 L.Ed.2d 25, 28 (1976) (per curiam); see Patterson v. New York, 432 U.S. 197, 210, 97 S.Ct. 2319, 2327, 53 L.Ed.2d 281, 292 (1977) (state must prove “all of the elements included in the definition of the offense” charged beyond a reasonable doubt); United States v. McClain, 545 F.2d 988, 1004, modified, 551 F.2d 52 (5th Cir.1977) (per curiam). The Supreme Court has also phrased the test in terms of “every fact necessary to constitute the crime charged.” Mullaney v. Wilbur, 421 U.S. 684, 685, 95 S.Ct. 1881, 1883, 44 L.Ed.2d 508, 511 (1975). In Patterson, however, the Court clarified Muilaney, stating: “Muilaney surely held that a State must prove every ingredient of the offense beyond a reasonable doubt....” 432 U.S. at 215, 97 S.Ct. at 2329, 53 L.Ed.2d at 295.
. E.g., United States v. Johnson, 700 F.2d at 186; United States v. Guy, 456 F.2d 1157, 1163 (8th Cir.), cert. denied, 409 U.S. 896, 93 S.Ct. 136, 34 L.Ed.2d 153 (1972).
. See Pullman-Standard v. Swint, 456 U.S. 273, 288, 102 S.Ct. 1781, 1789, 72 L.Ed.2d 66, 79 (1982) (“vexing nature of the distinction between questions of fact and questions of law”); Baumgartner v. United States, 322 U.S. 665, 671, 64 S.Ct. 1240, 1244, 88 L.Ed. 1525, 1529 (1944) (distinction “often not illuminating” and “never self-executing”).
. See Pullman-Standard, 456 U.S. at 289, & n. 19, 102 S.Ct. at 1790 & n. 19, 72 L.Ed.2d at 80 & n. 19.
. If it were appropriate to resolve this case on the “fact” and “law” distinction, we would reach the same result. The definition of a security is a matter of law. It is the judge’s duty to instruct the jury concerning that definition: the way in which a security is identified. Whether a particular piece of paper meets that definition, however, is for the jury to decide. Of course, the question whether a generic type of document, such as a traveler’s check or an equipment lease, may come within the reach of the statute’s prohibition is one of law. See, e.g., United States v. Wexler, 621 F.2d 1218 (2d Cir.) (equipment leases), cert. denied, 449 U.S. 841, 101 S.Ct. 119, 66 L.Ed.2d 48 (1980); Unit*1322ed States v. Gallipoli, 599 F.2d 100 (5th Cir. 1979) (airline tickets); United States v. Speidel, 562 F.2d 1129 (8th Cir.1977) (quitclaim deeds), cert. denied, 435 U.S. 915, 98 S.Ct. 1468, 55 L.Ed.2d 505 (1978).
. See United States v. Desmond, 670 F.2d 414 (3d Cir.1982).
. See generally, Morgan, A Brief History of Special Verdicts and Special Interrogatories, 32 Yale L.J. 575 (1922).
. See United States v. Heller, 635 F.2d 848, 856-57 (Em.App.1980) (court could not instruct jury that comparability of outlet had been established as a matter of law); United States v. Benedetto, 558 F.2d 171, 176-77 (3d Cir.1977) (court could not instruct jury that loans were “loanshark loans” as a matter of law); Greenfield v. United States, 341 F.2d 411, 412-13 (D.C.Cir.1964) (per curiam) (court could not instruct jury that pop bottle was dangerous weapon as a matter of law); DeCecco v. United States, 338 F.2d 797, 798 (1st Cir.1964) (court *1323could not instruct jury that defendant had failed to pay wagering tax as a matter of law).
. See United States v. Guy, 456 F.2d 1157 (8th Cir.) (obligations of the United States as a matter of law), cert. denied, 409 U.S. 896, 93 S.Ct. 136, 34 L.Ed.2d 153 (1972); United States v. Morris, 451 F.2d 969, 972-73 (8th Cir.1971) (“in federal custody” as a matter of law); United States v. Briddle, 443 F.2d 443, 447 (8th Cir.) (property of the United States as a matter of law), cert. denied, 404 U.S. 942, 92 S.Ct. 291, 30 L.Ed.2d 256 (1971); United States v. Jackson, 436 F.2d 39, 41-42 (9th Cir.1970) (government property as a matter of law), cert. denied, 403 U.S. 906, 91 S.Ct. 2209, 29 L.Ed.2d 682 (1971); United States v. Parisi, 365 F.2d 601 (6th Cir.1966) (bonded warehouse as a matter of law), vacated on other grounds sub nom. O’Brien v. United States, 386 U.S. 345, 87 S.Ct. 1158, 18 L.Ed.2d 94 (1967); Guy v. United States, 336 F.2d 595, 597 (4th Cir.1964) (per curiam) (apparatus was a still as a matter of law).
. Moore, 429 U.S. at 22, 97 S.Ct. at 30, 50 L.Ed.2d at 28.
. A security is:
[A]ny note, stock certificate, bond, debenture, check, draft, warrant, traveler’s check, letter of credit, warehouse receipt, negotiable bill of lading, evidence of indebtedness, certificate of interest or participation in any profit-sharing agreement, collateral-trust certificate, preorganization certificate or subscription, transferable share, investment contract, voting-trust certificate; certificate of interest in property, tangible or intangible; instrument or document or writing evidencing ownership of goods, wares, and merchandise, or transferring or assigning any right, title, or interest in or to goods, wares, and merchandise; or, in general, any instrument commonly known as a “security”, or any certificate or interest or participation in, temporary or interim certificate for, receipt for, warrant, or right to subscribe to or purchase any of the foregoing, or any forged, counterfeited, or spurious representation of any of the foregoing.
18 U.S.C. § 2311 (1976).
. See, e.g., United States v. Ackerman, 704 F.2d 1344 (5th Cir.1983) (false customs declaration); United States v. Howton, 688 F.2d 272 (5th Cir.1982) (false testimony to grand jury); United States v. Thompson, 637 F.2d 267 (5th Cir.1981) (perjury); United States v. Nixon, 634 F.2d 306 (5th Cir.) (same), cert. denied, 454 U.S. 828, 102 S.Ct. 120, 70 L.Ed.2d 103 (1981); United States v. Baker, 626 F.2d 512, 514 n. 4 (5th Cir.1980) (false statements to government agency); United States v. Bell, 623 F.2d 1132 (5th Cir. 1980) (false testimony to grand jury); United States v. Lichenstein, 610 F.2d 1272 (5th Cir.) (false statements to government agency), cert. denied, 447 U.S. 907, 100 S.Ct. 2991, 64 L.Ed.2d 856 (1980); United States v. Baptiste, 608 F.2d 666 (5th Cir.1979) (false testimony to grand jury), cert. denied, 450 U.S. 1000, 101 S.Ct. 1707, 68 L.Ed.2d 202 (1981); United States v. Cosby, 601 F.2d 754 (5th Cir.1979) (same); United States v. Schaffer, 600 F.2d 1120 (5th Cir.1979) (false statements to government agency); United States v. Taylor, 574 F.2d 232 (5th Cir.) (false income tax returns), cert. denied, 439 U.S. 893, 99 S.Ct. 251, 58 L.Ed.2d 239 (1978); United States v. Haynes, 573 F.2d 236 (5th Cir.) (same), cert. denied, 439 U.S. 850, 99 S.Ct. 154, 58 L.Ed.2d 153 (1978); see generally Annot., 60 A.L.R.Fed. 76 (1982); Annot., 49 A.L.R.Fed. 622 (1980 & Supp.1982). In Blackmon v. United States, 108 F.2d 572 (5th Cir. 1940), however, we held that it was not error to submit the question of the materiality of perjured testimony to the jury, although it should have been decided by the trial judge. Accord United States v. Moran, 194 F.2d 623 (2d Cir.), cert. denied, 343 U.S. 965, 72 S.Ct. 1058, 96 L.Ed. 1362 (1952). In Steadman v. SEC, 603 F.2d 1126 (5th Cir.1979), aff’d, 450 U.S. 91, 101 S.Ct. 999, 67 L.Ed.2d 69 (1981), we noted that the issue of materiality in failure-to-disclose cases is “a mixed question of law and fact and that divining the significance of the inferences a reasonable investor would draw from a given set of facts is peculiarly within the competence of the trier of fact.” 603 F.2d at 1130 (citing TSC Indus. v. Northway, Inc., 426 U.S. 438, 96 S.Ct. 2126, 48 L.Ed.2d 757 (1976)).
. United States v. Musgrave, 444 F.2d 755, 762 (5th Cir.1971) (emphasis added), cert. denied, 414 U.S. 1023, 94 S.Ct. 447, 38 L.Ed.2d 315 (1973), cited with approval in United States v. Jacquillon, 469 F.2d 380, 387 (5th Cir.1972), cert. denied, 410 U.S. 38, 93 S.Ct. 1400, 35 L.Ed.2d 604 (1973), and in United States v. Fischer, 531 F.2d 783, 787 n. 5 (5th Cir.1976), and in United States v. Buchanan, 585 F.2d 100, 102 (5th Cir.1978).
. The seminal case stating this principle is Quercia v. United States, 289 U.S. 466, 469, 53 S.Ct. 698, 699, 77 L.Ed. 1321, 1325 (1933), in which the Supreme Court held: “It is within [the judge’s] province ... to assist the jury in arriving at a just conclusion by explaining and commenting upon the evidence .... ” The Court reversed the defendant’s conviction because the trial judge’s observation that a witness wiping his hands while testifying was almost always an indication of lying was “a sweeping denunciation repudiatpng] as a lie all that the accused had said in his own behalf .... This was error and we cannot doubt that it was highly prejudicial.” Id. at 472, 53 S.Ct. at 700, 77 L.Ed. at 1326. The Court added:
Nor do we think that the error was cured by the statement of the trial judge that his opinion of the evidence was not binding on the jury and that if they did not agree with it they should find the defendant not guilty. His definite and concrete assertion of fact ... was not withdrawn. His characterization of the manner and testimony of the accused was of a sort most likely to remain firmly lodged in the memory of the jury and to excite a prejudice which would preclude a fair and dispassionate consideration of the evidence.
Id. See Buchanan, 585 F.2d at 102 (comments may not be “so highly prejudical” that instruction cannot cure any error); see also United States v. Dillon, 446 F.2d 598, 600-01 (5th Cir.1971); United States v. Dopf, 434 F.2d 205, 207-09 (5th Cir.1970); United States v. Garza, 426 F.2d 949, 954 (5th Cir.1970).
. We reinstate that portion of the panel opinion rejecting Johnson’s other claims, 700 F.2d at 176-77, and, therefore, affirm the judgment of conviction on Count Two. We note that the judge instructed the jury on Count Two that the telephone calls were wire signals as a matter of law. This instruction was improper. However, Johnson did not request that the issue be submitted to the jury and did not on appeal assign the instruction as error. We, therefore, do not consider this question. Cf. Commercial Standard Ins. Co. v. Bryce St. Apts., 703 F.2d 904, 908 (5th Cir.1983) (rule against raising issues for first time on appeal prevents “scanning the record for new theories”).