This is an action of tort to recover for personal injuries caused by the alleged negligence of the defendant’s employees. We have had occasion to consider the case twice before, 338 Mass. 107, and 341 Mass. 543. In the more recent decision we sustained the exception of the plaintiff to the direction of a verdict for the defendant.

The plaintiff lived in an apartment on the third floor of a building at 8% Chrome Street in Worcester. He was moving to another apartment and had purchased new furniture from the defendant in a ‘transaction whereby some of the plaintiff’s old furniture was taken by the defendant in part payment for the new. On the morning of July 29,1954, the defendant sent a truck with two of its employees, Bell and Fleming, to the plaintiff’s apartment to remove the furniture which it had acquired.

There was evidence that Bell was the driver of the truck and “supervisor” of the work of removal. Fleming was his assistant. After taking a bureau down the stairway *319which was narrow, with eight right angle turns, Bell decided that it would be easier to remove the rest of the furniture by lowering it to the street from the front porch of the apartment. He had brought in his truck a thirty foot strip of webbing two and one-half to three inches in width. With this webbing he and Fleming proceeded to lower several articles of furniture to the street. There remained a studio divan which was convertible into a bed by folding down the back and removing the arms. It was about six feet long, two and one-half feet wide, and was estimated to weigh from 125 to 200 pounds. It had six legs about four inches long, two at each end and two in the middle. The movers raised the divan so that the section between the legs at one end and the middle legs rested on the railing of the porch. One end of the webbing was tied to the divan and the other end held by Bell, after winding it once or twice around a post of the railing. The plaintiff, who had until then been absent, at that time returned to the apartment. Bell sent Fleming down to the porch on the second floor to help guide the divan in its descent and asked the plaintiff to assist in steadying the divan. The plaintiff consented and took a position on the left of the divan as one faces the street. Bell was on the right with his foot against the post, his shoulder against the divan, and holding the webbing with one hand. He “wiggled” the divan to get it straight before lifting it over the railing. In the process he gave it a push, described by the plaintiff’s daughter as a “lunge,” and the railing, on which the divan was leaning, collapsed. The porch end of the divan swung to its left, striking the plaintiff and throwing him to the street below.

At the conclusion of the evidence a motion of the defendant for a directed verdict was denied and the defendant excepted. The jury returned a verdict for the plaintiff.

“It could have been found,” as we said in a former opinion on substantially the same evidence, “that Bell and Fleming had at least implied authority from the defendant to obtain assistance from the plaintiff.” Peloquin v. Robert Northridge Furniture Co. 341 Mass. 543, 545, and cases cited. It could not be ruled that the plaintiff was guilty of *320contributory negligence or that there was no evidence of negligence on the part of the defendant’s.employees. These were questions of fact for the jury. They could find that the accident was caused by Bell wiggling the divan in such a manner that its middle legs, which were on the inside of the railing, were pushed against it with such force that it was caused to break. Bell’s conduct plainly could be found to be negligent but we cannot accede to the defendant’s contention that if it were so found the plaintiff must be held to have participated in his negligence. The evidence fails to show that the plaintiff had any reason to expect that Bell in preparing to lift the legs of the divan over the railing would manipulate it in such manner that it would create a dangerous situation.

The defendant excepted to the admission of testimony by the plaintiff’s daughter that she heard Bell and Fleming say that it was impossible to move the remainder of the furniture by the stairway and that they would have to do it by the front porch. The defendant had admitted in answer to an interrogatory that the men decided “it would be easier to lower the rest of the furniture down over the outside of the building. ’ ’ The answer was in evidence and the testimony to which exception was taken was substantially cumulative. If technically inadmissible, the defendant was not harmed. Bendett v. Bendett, 315 Mass. 59, 65-66, and cases cited. There was no reversible error.

No error appears in the admission of other evidence to which the defendant excepted. The daughter testified that her father asked Bell if he thought the railing was strong enough to “carry this heavy divan” and Bell answered, “We’ve been doing it all morning and nothing’s happened so far. It’s plenty strong enough to carry this-divan.” The question and answer were material to the question of the plaintiff’s due care if for no other reason. Other testimony by the same witness that the push given to the divan by Bell was a “lunge” was allowed to stand. It was a proper descriptive term meaning, according to dictionary definition, a sudden thrust.

*321A medical witness of the plaintiff in testifying to the plaintiff’s injuries was permitted to use a “Chart of Oste-ology” as a chalk. Permission to use a chalk is a matter of judicial discretion. The chart was exhibited on the blackboard after a conference at the bench and nothing appears in the record to show that its use was improper. Everson v. Casualty Co. of America, 208 Mass. 214, 220-221.

The defendant excepted to the denial of its motion for a new trial on the ground that the verdict was against the weight of the credible evidence. It contended that evidence presented by several of the plaintiff’s witnesses was so greatly at variance with their testimony at previous trials that it was unworthy of belief and that justice required another trial. An examination of the cross-examination of these witnesses shows certain differences between their testimony at the instant trial and at the previous trials; but not of such nature that it can be said the judge erred in denying the defendant’s motion.

Exceptions overruled.