If the obligation upon which the action is brought is not assumed by voluntary agreement, but it has been imposed by the law in connection with the surrounding facts and circumstances of the case, certain forms of subsequent impossibility, in the popular sense of the term, which arise without the fault of the promisor, may discharge him from liability.1 A common carrier, whose liability to transport and deliver is implied from the circumstances of his accepting goods for transportation, is discharged by any subsequent impossibility, which amounts to an act of God,2 or an act of the public enemy,3 though in other cases he is liable as an insurer.4

The term "act of God" is an unfortunate expression. It is used to describe natural forces as distinct from the consequences of human action,5 in which no human act has contributed to the loss. An unexpected freezing of a river,6 or an unexpected and unprecedented flood,7 or an earthquake,8 or an unprecedented snow storm,9 or a tornado or unprecedented wind storm,10 is an act of God in this sense. To effect a discharge of liability in such cases, the direct and sole cause of the loss must be the act of God.11 If the negligence of the carrier contributes to the loss,12 as where through his negligence the goods are exposed to a flood,13 or to a storm,14 and such exposure might have been prevented by reasonable care on his part, the fact that an act of God is in part the operating cause of the loss does not discharge his liability. If the carrier neglects to employ reasonable means of finding the goods after the flood, he is liable therefor.15 If a flood (such as the Johnstown flood) causes a wreck, and the carrier neglects to protect the goods, which are plundered, the negligence of the carrier to guard the goods contributes to the loss and the carrier is liable.16

1 Hick v. Rodocanachi [1891] 2 Q. B. 026; Seaboard Air Line Ry. v. Mullin, 70 Fla. 450, L. R. A. 1916D, 982, 70 So. 467 (obiter); Armstrong v. Illinois Central Railroad Co., 26 Okla. 352, 29 L. R. A. (N.S.) 671, 109 Pac 216.

2 Gulf Coast Transportation Co. v. Howell, 70 Fla. 544, L. R. A. 1916D, 974, 70 So. 667 (obiter); Wald v. Ry., 162 Ill 545, 63 Am. St Rep. 332, 36 L. R. A, 356, 44 N. E. 888; Shellabarger Ele-vator Co. v. Illinois Central Railroad Co., 278 Ill. 333, L. R. A. 1917E, 1011, 116 N. E. 170 (obiter); Armstrong v. Illinois Central Railroad Co., 26 Okla. 352, 29 L. R. A. (N.S.) 671, 109 Pac. 216; St, Louis & San Francisco R. R.

Co. v. Dreyfus, 42 Okla. 401, L. R. A. 1915D, 647, 141 Pac. 773 (obiter).

A constitutional provision fixing a carrier's liability will be construed as containing an implied exception as to acts of God or the public enemy. Shellabarger Elevator Co. v. Illinois Central Railroad Co., 278 Ill. 333, L. R. A. 1917E, 1011, 116 N. E. 170.

3 Shellabarger Elevator Co. v. Illinois Central Railroad Co., 278 Ill 333, L. R. A, 1917E, 1011, 116 N. E. 170 (obiter); Bland v. Adams Express Co., 62 Ky. (1 Dur.) 232, 85 Am. Dec. 623; Lewis v. Ludwick, 46 Tenn. (6 Cold.) 368, 98 Am. Dec. 454.

4 For the common law liability of the common carrier, see Sec. 740.

5 England. Forward v. Pittard, 1 T. R. 27.

Colorado. Blythe v. Denver & R. G. Ry., 15 Colo. 333, 22 Am. St. Rep. 403, II L. R. A. 615, 25 Pac. 702.

Florida. Seaboard Air Line Ry. v. Mullin, 70 Fla. 450, L. R. A. 1916D, 982, 70 So. 467.

Oklahoma. Armstrong v. Illinois Central Ry., 26 Okla. 352, 20 L. R. A. (N.S.) 671, 109 Pac. 216.

South Carolina. Slater v. South Carolina Ry., 29 S. Car. 96, 6 S. E. 936.

The fear of collusion between the common carrier and thieves, led to the adoption of this term so as to indicate the liability of the common carrier for all losses which could be attributed to human action, and his non-liability only in cases in which the loss could not be attributed to human agency.

6 Crosby v. Fitch, 12 Conn. 410, 31 Am. Dec. 745.

7 Alabama. Smith v. Ry., 91 Ala. 455, 24 Am. St. Rep. 929, 11 L. R. A. 619, 8 So. 754.

California. Ryan v. Rogers, 96 Cal. 349, 31 Pac. 244.

Maine. Libby v. Ry., 85 Me. 34, 20 L. R. A. 812, 26 Atl. 943.

New York. Read v. Spaulding, 30 N. Y. 630, 86 Am. Dec. 426.

Ohio. American Express Co. v. Smith, 33 O. S. 511, 31 Am. Rep. 561.

Oklahoma. Chicago, Rock Island & Pacific Railroad Co. v. Logan, 23 Okla. 707, 29 L. R. A. (N.S.) 663, 105 Pac. 343 (obiter); Armstrong v. Illinois Central Railroad Co.. 26 Okla. 352, 29 L. R. A. (N.S.) 671, 109 Pac. 216.

8 Slater v. South Carolina Ry. 29 S. Car. 90, 6 S. E. 936.

9 Jones v. Minneapolis Ry.. 01 Minn. 229, 103 Am. St. Rep. 507, 97 N. W. 893; Feinberg v. Delaware, Lackawanna & Western Ry., 52 N. J. L. 451, 20 Atl. 33; St. Louis & San Francisco R. R. Co. v. Dreyfus. 42 Okla. 401, L. R. A. 1915D, 547, 141 Pac. 773 (obiter).

lO Blythe v. Denver Ry., 15 Colo. 333. 22 Am. St. Rep. 403, 11 L. R. A. 615. 25 Pac. 702.

11 Kentucky. Styles v. Louisville &, X. R. Co., 129 Ky. 175, 18 L. R. A. (N.S.) 86, 110 S. W. 820.

Michigan. Michigan Central Ry. v. Burrows, 33 Mich. 6.

Missouri. Davis v. Ry., 89 Mo. 340.

Ohio. Daniels v. Ballentine, 23 O. S 532, 13 Am. Rep. 264.

Oklahoma. St. Louis & Santa Fe Ry. v. Dreyfus, 42 Okla. 401, L. R. A. 1915D, 547, 141 Pac. 773.

Pennsylvania. Lloyd v. Haugh & K. Storage & T. Co., 223 Pa. St. 148, 21 L. R. A. (N.S.) 188, 72 Atl. 516.

12 Arkansas. Jonesboro Lake City & Eastern Ry. v. Dunnavant, 117 Ark. 451, 174 S. W. 1187.

Florida. Gulf Coast Transportation Co. v. Howell, 70 Fla. 544, L. R. A. 1916D, 974, 70 So. 567; Seaboard Air Line Ry. v. Mullin, 70 Fla. 450, L. R. A. 1916D, 982, 70 So. 467 (obiter).

Louisiana. National Rice Milling Co. v. New Orleans & Northeastern Ry., 132 La. 615, 61 So. 708 (obiter).

Nebraska. Wabash Ry. v. Sharpe, 76 Neb. 424, 124 Am. St. Rep. 823, 107 N. W. 758; Sunderland Bros. Co. v. Chica-

The term "act of God" is not equivalent, however, to "overpowering force" or to "inevitable casualty."17 Considerations of public policy, the chief of which was the danger of collusion between the common carrier and robbers,18 caused the courts to hold the common carrier to his liability as insurer of the goods in all other cases, outside of the act of God and the public enemy, even if the loss or injury to the goods was due to inevitable casualty or overpowering force.19 The act of a mob is not the act of the public enemy within the meaning of this rule, and the carrier is liable for damage inflicted by a mob on goods in his custody as carrier.20 He is also liable for damage due to fire which was occasioned by human agency, although he is not at fault, and although he could not have prevented the loss or injury.21 go. Burlington & Quincy Ry., 89 Neb. 660, 131 X. W. 1047.

Oklahoma. Chicago, Rock Island & Pacific Railroad Co. v. Logan, 23 Okla. 707. 29 L. R. A. (N.S.) 663, 105 Pac. 343; St. Louis & San Francisco R. R. Co. v. Dreyfus, 42 Okla. 401, L. R. A. 1915D, 547, 141 Pac. 773.

South Carolina. Ferguson v. Southern Ry., 91 S. Car. 61, 74 S. E. 129.

Washington. Smith v. Trading Co., 20 Wash. 580, 44 L. R. A. 557, 56 Pac. 372.

13 Arkansas. Jonesboro, Lake City & Eastern Ry. v. Dunnavant, 117 Ark. 451, 174 S. W. 1187.

Florida. Gulf Coast Transportation Co. v. Howell, 70 Fla. 544, L. R. A. 1916D, 974, 70 So. 567; Seaboard Air Line Ry. v. Mullin, 70 Fla. 450, L. R. A. 1916D, 982, 70 So. 467 (obiter, as delay in transportation was not regarded as proximate cause of loss).

Louisiana. National Rice Mill Co. v. New Orleans & N. E. Ry., 132 La. 615 61 So. 708.

Nebraska. "Wabash Ry. v. Sharpe 76 Neb. 424, 124 Am. St. Rep. 823, 107 N. W. 758; Sunderland. Bros. Co. v. Chicago, Burlington & Quincy Ry., 89 Neb. GC0, 131 N. W. 1047.

South Carolina. Ferguson v. Southern Ry., 91 S. Car. 61, 74 S. E. 129.

14 St. Louie & San Francisco R. R. Co. v. Dreyfus, 42 Okla. 401, L. R. A. 1915D, 547, 141 Pac. 773.

15 Chicago, Rock Island & Pacific Railroad Co. v. Logan. 23 Okla. 707, 29 L. R. A. (N.S.) 663, 105 Pac. 343.

16 Lang v. Ry., 154 Pa. St. 342, 35 Am. St. Rep. 846, 20 L. R. A. 360, 26 Atl. 370.

17 Trent & Mersey Navigation Co. v. Wood, 4 Dougl. 287; Missouri Pacific Ry. v. Nevill, 60 Ark. 375, 46 Am. St. Rep. 208, 28 L. R.. A. 80, 30 S. W. 425; Merchants' Despatch Co. v. Smith, 76 Ill. 542; Merritt v. Earle, 29 X. Y. 115.

I8 Forward v. Pittard, 1 T. R. 27.

19 Missouri Pacific Ry. v. Nevill, 60 Ark. 375, 46 Am. St. Rep. 208, 28 L. R. A. 80, 30 S. W. 425; Merchants' Despatch Co. v. Smith, 76 Ill. 542; Pittsburg, C. C. & St. L. R. Co. v. Chicago, 242 Ill. 178, 44 L. R. A. (N.S.) 338, 89 N. E. 1022.

Even in jurisdictions in which the act of a tenant for years in holding over after his term, is held to make him a tenant for years without regard to his actual intention, such consequence does not follow if his act in holding over is due to inevitable casualty,22 such as illness,23 or inability to secure means of moving the goods.24 If the holding over is due to the illness of a subtenant, who is in the premises in violation of a covenant against subletting, the tenant will be treated as a tenant from year to year, if the lessor so elects,25 on the theory that the impossibility would not have arisen if the tenant had performed his covenant.

Since these are cases in which the liability is imposed by law, and not created by contract, further discussion here is unnecessary.