However, as the evidence disclosed, the jury could have concluded on the basis of expert testimony that the defendant's care and treatment caused no injury to plaintiff in addition to that sustained by the falling of the tree top upon him. A party has a right to have the jury instructed on his theory of recovery or defense if that theory is supported by facts in evidence or by reasonable inference from facts in evidence. ( Smith v. Ford (1976), 43 Ill. App.3d 407, 356 N.E.2d 1306.) In view of the evidence adduced at trial, the trial court did not err in giving the second paragraph of IPI Civil 2d No. 12.05.

He found the witness' qualifications unacceptable, and his preliminary questions to Steindler on cross-examination properly allowed Steindler an opportunity to explain what the State must have felt were discrepancies or misrepresentations. Cf. Smith v. Ford (1976), 43 Ill. App.3d 407 (impeachment must be preceded by calling the attention of the witness to be impeached to the alleged omissions and giving such witness the opportunity to explain). Further, it has been held to be error for the prosecutor to ask a defense witness a question designed to lay a foundation for an impeachment unless he is prepared to follow up a denial of the question with proof of the inference contained in the question.

• 2 In general, experiments are incompetent as evidence unless the essential conditions of the experiment are shown to be the same as those existing at the time of the accident. ( Ryan v. Blakey (1979), 71 Ill. App.3d 339, 389 N.E.2d 604; Smith v. Ford (1976), 43 Ill. App.3d 407, 356 N.E.2d 1306.) However, when an experiment is not represented to be a reenactment of the accident and it deals with one aspect or principle directly related to the cause or result of the occurrence, the exact conditions of the accident need not be duplicated. Skalon v. Manning, Maxwell Moore, Inc. (1970), 127 Ill. App.2d 145, 262 N.E.2d 146; Johnson v. Chicago North Western Ry. Co. (1956), 9 Ill. App.2d 340, 348, 132 N.E.2d 678.

Thus the effect of the trial court's refusal of the two instructions was to prevent the jury from considering section 1205. A party has a right to have the jury instructed on his theory of recovery or defense if that theory is supported by facts in evidence or by reasonable inference from facts in evidence. ( Smith v. Ford (1976), 43 Ill. App.3d 407, 356 N.E.2d 1306.) Instructions concerning violation of a statute should not be given unless the evidence is adequate to support a finding that a violation actually occurred. ( Figarelli v. Ihde (1976), 39 Ill. App.3d 1023, 351 N.E.2d 624; IPI Civil No. 60.00.)

The defendant had a right to have the jury instructed on its theory of the case which was supported by facts in evidence or by reasonable inferences from facts in evidence. ( Smith v. Ford (3d Dist. 1976), 43 Ill. App.3d 407, 411, 356 N.E.2d 1306.) We do not find that the instructions considered in their entirety were so misleading or prejudicial as to warrant reversal.

As can be seen from our discussion of the facts such a view clearly was supported by the evidence; consequently the defendant had a right to have the instruction presented to the jury. Pantaleo v. Gamm, 106 Ill. App.2d 116, 245 N.E.2d 618; Smith v. Ford, 43 Ill. App.3d 407, 356 N.E.2d 1306; Garrett v. Babb, 24 Ill. App.3d 941, 322 N.E.2d 217. Plaintiff's final contention is that the trial court erred in refusing her tendered instructions Nos. 13 and 23. She, however, has not specified in her brief why such refusal was error.

This court would have been fully justified in refusing to review these instructions at all in view of the fact that the excerpts from the record submitted herein do not contain all of the instructions tendered or given, and especially because the proceedings at the conference on instructions, as excerpted, contain no reference whatsoever to these two instructions. Smith v. Ford (1976), 43 Ill. App.3d 407, 356 N.E.2d 1306; Geleto v. Giglietti (1976), 40 Ill. App.3d 226, 352 N.E.2d 1. • 10, 11 However, we have thoroughly examined the record and find that the trial court properly excluded defendant's proposed instruction 7. Briefly stated, the only competent evidence bearing on this issue was the testimony of Gaslite's president, Mr. Klein, who stated that after NI-Gas announced there would be no campaign, Gaslite expended a certain sum of money on advertising, increased its efforts to sell gas lights and gas grills to other parties, and did in fact increase the sales to those parties, but not to the extent of its loss of sales to NI-Gas.