The test of reasonable foresight arising out of The Wagon Mound clearly takes into account such things as scientific knowledge at the time of the negligent act. The question to be asked in determining the extent of liability is, 'is the damage of such a kind as the reasonable [person] should have foreseen?' This does not mean that the defendant should have foreseen precisely the sequence or nature of the events.

　　This is illustrated in the case of Hughes v Lord Advocate (1963), where employees of the Post Office, who were working down a manhole, left it without a cover but with a tent over it and lamps around it. A child picked up a lamp and went into the tent. He tripped over the lamp, knocking it into the hole. An explosion occurred and the child was burned. The risk of the child being burned by the lamp was foreseeable. However, the vaporisation of the paraffin in the lamp and its ignition were not foreseeable. It was held that the defendants were liable for the injury to the plaintiff. It was foreseeable that the child might be burned and it was immaterial that neither the extent of his injury nor the precise chain of events leading to it was foreseeable.