The plaintiff claims to have been injured while a passenger on one of defendant’s west-bound cars on Eighth street in Kansas City, Missouri. The injury is practically conceded to have been the result of a collision between two of defendant’s cars. The charge of negligence is that, “on account of the negligence of the defendant, its agents and employees, said car on which the plaintiff was a passenger collided violently with another of defendant’s cars on said north track of said Eighth street, throwing plaintiff violently against a portion of the car on which plaintiff was a passenger.” The plaintiff proved that while he was a passenger on one of defendant’s cars it collided with another car on the same track, whereby he was injured. He thus made out a prima-facie case.

The defendant introduced evidence tending to show that the collision was an unforeseen accident which was caused by the bursting of a union in the air-brake, which had the effect of letting the air escape and whereby the persons in charge of the car were deprived of the means of preventing the collision. That the defect in the air-brake that caused it to burst was of such a character that it could not have been discovered by inspection. The jury returned a verdict for the defendant, which the court set aside on the motion of the plaintiff, and defendant appealed.

The plaintiff assigned various grounds for a new trial. The court gave as a reason for granting a new trial two of the grounds assigned, viz.: That the verdict of the jury was against the weight of the evidence, and that the court erred in giving defendant’s instruction numbered six. Said instruction six reads as follows: *82“When something unusual occurs, but such unusual occurrence is not the result of an unusual act of the defendant, and the defendant has so far as it is concerned, been pursuing its usual course, which had ‘theretofore been done in safety, then the unusual occurrence is what is called an accident. If plaintiff received his injuries as the result of some occurrence which careful and prudent men in the situation of defendant’s agent would not reasonably have anticipated or expected, then such occurrence is what, in law, is termed an accident, and the defendant is not liable for the resulting injury to plaintiff.”

The defendant seeks to justify the instruction by citation of certain decisions of this court. In Saxton v. Railroad, 98 Mo. App. 494, we find the following. “It has been said that when something unusual occurs which injures plaintiff, but such unusual occurrence is not even inferentially the result of an unusual act and the defendant, so far as he is concerned, has been pursuing his usual course which heretofore had been done in safety, then the unusual occurrence is what is called an accident.” And so it is said in Wendall v. Railroad, 100 Mo. App. 556. In so far as the instruction undertakes to define what constitutes an accident, it is in accord with the decisions referred to. But is goes further and includes an element in its application to the case, that the definition does not justify, i. e., the closing sentence, “If plaintiff received his injuries as the result of some occurrence which careful and prudent men, in the situation of defendant’s agents, would not have reasonably anticipated, or expected, then such occurrence is what, in law, is termed an accident, and the defendant is not liable for the resulting injury.” This was a substitution for the definition taken from the books. What “careful and prudent men in the situation of defendant’s agents would not reasonably have anticipated or expected,” at best is a very equivocal expression. The *83word reasonably, has different significations. It sometimes means tolerably, or moderate. Its meaning when applied to a time within which a thing is to be done has given the courts much trouble in its application to the particular facts of the case. What is reasonable is most generally a question upon which the minds of men do not agree. What one would think was reasonable another might think unreasonable. The instruction left the jurors to enter the field of speculation and conjecture. If the collision was the result of an accident, that was the end of the matter. It is folly to talk of anticipating an accident. An accident is something unexpected and unavoidable. At best, the instruction tended to confuse and mislead the jury, and the judge who heard the evidence was in a better condition to know what effect it had on the jury than we are.

“An accident is an event from a known cause, or an unusual and unexpected event from a known cause; casualty.” If the bursting of the union or joint of the air-brake of the car was an unusual and unexpected event, the collision was an accident, and the defendant was not liable. That this union of the air-brake did burst seems to be a conceded fact. A careful study of the evidence has convinced us that the bursting of the air-brake under the circumstances was not such an event that could be called unusual and might have been anticipated by the exercise of ordinary care, much less the highest degree of care. It was shown that the track in question was wet and not sanded; that the union in question was made of the best material, and that one never bursted before or since under the same conditions; that the break in the metal was fresh and clean with no evidence whatever of a prior weakening; that the pressure of the air at all times was uniformly eighty pounds to the square inch, consequently the strain was no greater when the car was started down the grade than when on the level. Taking all these facts into consideration *84with the statement of the motorman that he first heard the noise of the escaping air about the time it struck the car in front, goes to show in our opinion that the break was occasioned by the collision. We do not see how it could have occurred otherwise. It is true that the motorman was somewhat uncertain as to when he first heard the escaping air, but we think it safe to say that a fair construction of his evidence is as we have stated it. But, admitting it to be otherwise, we cannot escape the conclusion that the only way in which the union was bursted was by the result of the collision. We are of the opinion that the court was justified in holding that the verdict was against the weight of the evidence.

• The defendant’s eighth instruction is subject to the same objection as that we have noted as to its sixth. The plaintiff’s fourteenth instruction should have been given, as it properly defines the degree of care required of defendant under the facts of the case.

For the reasons given, the action of the court in granting a new trial is affirmed.