Sec 310

Perfect caution, however, is not required. Were it required, business could not be efficiently conducted. It would be possible, for instance, for a railroad company not only to place watchers along the whole line of their road, but to place watchers to watch the watchers. To require this, however, would be to stop railroad transportation, as no railroad company could carry such a burden. It would be possible, also, to prevent wooden houses from being burned by keeping them perpetually drenched in water; but this would be equivalent to saying that no wood should be used in the construction of houses. Hence it is not necessary to sustain the defence of casus, that the calamity could not have been possibly averted. It is enough if it could not have been averted by the exercise of that diligence which is usual among prudent and competent persons charged with the particular duty whose non discharge is in the case in question excused by casus.2 Thus where a sudden frost closes the naviga-

But perfect caution not required.

1 Arthur v. Wynne. L. R. 14 Ch. D. 603. In Lilley v. Doubleday (L. R. 7 Q. B. D. 510), the plaintiff was shown to have forwarded to the defendant goods for the purpose of being warehoused. The contract between the parties was, that the goods should be deposited by the defendant at a store at a specific place; instead of which he deposited a part of them in a place where, without any particular negligence on his part, a fire took place by which they were destroyed. The only point at issue was, whether the fact that the defendant had deposited the goods in a different place from that in which he had contracted to deposit them, rendered him liable for their destruction by means of a fire which they would have escaped if they had been warehoused in accordance with the contract. The. court ruled this point against the defendant. " If a bailee," said Mr. Justice Grove, " el-to deal with the property entrusted to him in a way not authorized by the bailor, he takes upon himself the risks of so doing, except where the risk is independent of his acts, and inherent in the property itself." See comments in London Law Times, Feb. 18, 1882.

2 Wh. on Nag. sec 116, 123; Idle v. Thornton, 3 Camp. 274: Nichols <•. Maryland, L. R. 10 Ex. 255; Railroad tion of a river a month earlier than usual, this is a defence to a carrier, though it is possible he might have delivered the goods had he started them two months earlier.1 So it is a defence that a rail has been broken by a cold snap utterly unprecedented in its severity and earliness; though it is possible to conceive of rails constructed of such a temper and encased with such care as to resist even the extremest cold.2 On the other hand a collision, which might have been avoided had a proper chart been taken;3 an explosion of a boiler, which might have been avoided by a proper supply of water;4 or a destruction by freezing, which might have been avoided by the packing prudent carriers under such circumstances are accustomed to give;5 cannot be imputed to casus.6.