certain additional sum in case it proves more productive. Royalty is generally a certain per cent on all mineral removed, and of course if no mineral is found the lessor receives no royalty. But dead rent is payable unconditionally, regardless of whether mineral is found or not;2 and where a provision for dead rent is incorporated in a lease the lessee, cannot avoid liability therefor by offering to pay for such mineral as was found; 3 nor would his liability be affected by the fact that the mineral was not worth the working, or was not actually worked. However, if by misrepresentation on the part of the lessor the lessee had been impelled to enter into the agreement and the mineral represented to be in place had been previously cut out, then the payment of the rent could be avoided by the lessee on account of the mistake under which he labored when he contracted the obligation.6

1 MacSwinney on Mines, supra. Royalty is said to be a quasi rent. Campbell v. Leach, Amb. 740. See also MacS. on Mines, 218. The obligation to pay royalty cannot be implied. Jegan v. Vivian, 6 Ch. 757; Crong v. Adams, 5 B. P. C. 588. But royalty on all ore mined by lessee, cannot be reduced below the fixed per cent because quality is inferior. Sharp v. Behr (Pa. 1902), 117 Fed. Rep. 864.

2 Haywood v. Cope, 25 Beav. 140; Phillipp v. Jones, 9 Sim. 519; Mellers v. Devonshire, 16 Beav. 252; Gowan v. Christie, L. R. 2 S. C. & D. 273.

3 Phillipp v. Jones, supra; MacSwinney on Mines, p. 114.

♦ Strelley v. Pearson, L. R. 15 Ch. D.-113; Haywood v. Cope, supra. Jones v. Reynolds, 7 C. & P. 335; Jegan v. Vivian, supra. But if lessee only covenant to work mine so long as profitable, rent could not be recovered when it became unprofitable. Jones v. Shears, 7 C. & P. 446. See as to average clause to protect lessee, Bishop v. Goodwin, 14 M. & W 260.

Ridgeway v. Sneyd, Kay, 627; Green v. Sparrow, 3 Swanst. 408. If the covenant to work is absolute, in the condition the mine or quarry may be in, at date of lease, and a fixed rent is provided for, the lessee cannot defeat the rent because the lease was not profitable. Skilly v. Logan (Fa. 1902), 21 Pa. Sup. Ct. 106. But for recovery, where terms of covenant clearly contemplate that lease shall be profitable, see Cleopatra Min. Co. v. Dickinson (Wash. 1902), 68 Pac. Rep. 456; Hewitt Iron Min. Co. v. Desson Co. (Mich. 1902), 89 N. W. Rep. 365.

§ 130. Same Covenant to mine certain amount. It sometimes occurs that the lessor, in addition to the covenant on the part of the lessee to work the mine continuously, requires him to produce a certain amount of ore within fixed intervals, during the continuance of the lease. When such a covenant is inserted in a lease it is independent of a covenant for dead rent or royalty, and a settlement of rent or royalty for the amount of ore actually mined will not release the lessee for the breach of a covenant to produce a certain quantity; 2 and where the lessee covenants, unconditionally, to raise a specified quantity and to pay royalty on such an amount as he covenants to raise,3 he will be liable for the full amount of rent on breach of the covenant, regardless of whether the mineral existed at the time, and will not be permitted to set up the impossibility of performance as a release from his covenant, even though it were impossible for him to raise the stipulated quantity. But although this is the law, it is nevertheless at times a harsh rule to enforce against the lessee, and where the covenant is not absolute to raise a specified quantity, or where, from the other covenants in the lease, the condition could reasonably be implied that the lessee only intended to raise such quantity, in case it existed at the time, or in case he only covenants to produce such

1 MacSwinney on Mines, p. 220; Jegon v. Vivian, L. R. 6 Ch. App. 742; 6 Mor. Min. Rep. 420.

2 Powell v. Burroughs, 54 Pa. St. 329.

3 Marquis of Butte v. Thompson, 13 M. & W. 487; s. c. 14 L. J. Ex. 95; Clifford v. Watts, L. R. 5 C. P. 577.

4 Butte v. Thompson, supra; Clifford v. Watts, supra; Powell v. Bur roughs, 54 Pa. St. 329; Jervis v. Tomkinson, 1 H. & M. 195; MacSwinney on Mines, p. 220; Skillen v. Logan, 21 Pa. Sup. Ct. 106.

Butte v. Thompson, 13 M. & W. 487.

6 Clifford v. Watts, L. R. 5 C. P. 577. cannot be recovered, when merchantable

Royalty on minimum quantity ore is exhausted. Diamond

Iron Min. Co. v. Buckeye Co., 70 Minn. 500; 73 N. W. Rep. 507; Bannan v. Graeff, 186 Pa. St. 648; 40 Atl. Rep. 805.

quantity and pay the stipulated rent as it may be possible to find under the demised premises, then, in either event, he will only be liable in case the requisite amount of ore existed at the time.1 Before he could be released from his covenant, however, even in case of this implied or express condition annexed thereto, he must necessarily show that he has performed the same so far as was in his power to do,2 and if he has made no effort to find the minerals, or has not made such diligent search as to have found them, in case they existed, he will still be liable on his covenant for the rent on the amount of ore contracted for.3

§ 131. Assignment of lease. The assignment of a lease is the transfer of the lessee's interest in the tenancy. It may be effected either by operation of law, or by voluntary conveyance. Every lease for a term of years is capable of being assigned, whether the term is in possession, or in futuro,5 and every lessee, except one holding under a tenancy at will, has the power to assign his interest in

1 Fooley v. Addenbrook, 13 M. & W. 174; s. c. Mor. Min. Dig. 106; MacSwinney on Mines, 220-221; Clifford v. Watts, L. R. 5 C. P. 577. 2 Ante, idem; Powell v. Burroughs, supra.

3 See Clifford v. Watts; Jervis v. Tomkinson, and MacSwinney on Mines, supra. "Where the lessee of a mineral right, required to pay a sum for each ton of phosphate taken from the land, the same to be determined by the market price of the phosphate, — afterwards adopts a new method, by which the mineral is divided into two classes, selling at different prices, the royalty is to be computed by taking the combined values of the two products which the phosphate produces, though the phosphate has a market value before its separation. Where one class of phosphate so produced is crushed and put in bags, which was not required under the method in use when the lease was executed, the lessor is not required to have a portion of such additional expense deducted from her royalties." Harlan v. Cent. Phos. Co. (Tenn. 1901), 62 S. W. Rep. 614.

4 Taylor's Land. & Ten., §§ 426, 427.

Idem, 430, p. 6, Vol. II. But see Austin v. Huntsville Coal Co., 72 Mo. 535.

the tenancy, unless he is prevented from so doing by his lease; 1 but when the lease is required by the statute of frauds to be in writing, the assignment must also be in writing.2 The assignment, however, need not be in any particular form, and any words will be sufficient that clearly show the intention of the parties.3 But in order to constitute one an assignee of a lease, he must claim through, or be in of the same estate as the person whom he succeeds, and although the fact of his being in possession of the premises is presumptive evidence of his being an assignee, he will not be entitled to the rights and privileges of an assignee, if he holds under, or by virtue of an elder title.5

§ 132. Same - Rights and liabilities of assignee.— The lessee's privity of estate is transferred by assignment to his assignee, but his privity of contract is not. He therefore remains liable on his express covenants, but his liability on his implied covenants is transferred to his assignee; he is entitled to indemnity, however, from his

1 "Even a possibility of a term is assignable in equity for a good consideration." Taylor, § 430.

2 Welsh v. Schuler, 6 Daly, 412.

3 Spicer v. Banker, 45 Mich. 630. No consideration need be expressed. Hastings v. McKinley, 1 E. D. Smith, 273. For case where assignment was of personalty only and the assignee was not liable on covenant for rent, see Heller v. Daily (Ind. App. 1902), 63 N. E. Rep. 490.

4 Choworth v. Phillipps, Moore, 876; Roach v. Wadham, 6 East, 289; Taylor's Land. & Ten., § 429, p. 6.

5 Ante, idem; Jeherwood v. Oldknow, 3 M. & W. 382. See as to rebuttal of presumption arising from possession, Shee v. Gray, 15 Ir. C. L. 296; also see Carver v. Palmer, 33 Mich. 342. An executed contract for assignment of a mining lease, will supersede an earlier contract between lessor and another, not executed. Dermott v. Priddy (Mo. App. 1903),

71 S. W. Rep. 1088.

6 Taylor's Land & Ten., § 436.

7 Ante, idem.

8 Gordon v. George, 12 Ind. 408.

assignee, in case he should be made to pay for a breach of covenant by his assignee.1 The assignee is bound by the covenants which run with the land, and is liable to the original lessor, for royalty or rent accruing after assignment, even before he comes into possession of the premises; 2 he takes the assignor's interest in the estate subject to the equities between the original parties, and is liable on the covenants annexed to the estate, while he is in possession; 3 but his liability ceases with his possession and he is not liable on collateral covenants, nor for breaches committed by those who preceded him in the enjoyment of the premises.5

acts of the

The date of

§ 133. Duration of tenancy.- The duration of a tenancy depends both upon the lease and the parties after the contract has gone into effect. the commencement of an estate for years must be fixed and certain, and although the tenancy need not commence immediately on the execution of the lease, it must be capable of being made certain by a reference to some event or

1 See Rensseller v. Hayes, 19 N. Y. 68.

2 Carter v. Hammett, 18 Barb. 608; Mariner v. Crocker, 18 Wis. 251. But an assignee is not liable on prior agreements of assignor with a third party to take out certain quantity of ore. Preston v. McCall, 7 Grat. (Va.) 121. But see Fisher v. Milliken, 8 Pa. St. 111; s. c. Mor. Min. Rep., Vol. 8, p. 395.

3 Fisher v. Milliken, supra.

Turner v. Reynolds, 23 Pa. St. 199; Preston v. McCall, supra.

5 Nor would he be entitled to take advantage of a breach occurring on the part of the lessor before he came into possession. Shelby v. Hearne, 6 Yerg. 512; Taylor's Land. & Ten., § 445. But an assignee under a mere agreement to take possession, is not liable, even though he enters into possession. Cox v. Bishop, 8 DeG. M. & G. 815; Walters v. Northern C. M. Co., 5 DeG. M. & G. 629.

6 Patterson v. Hubbard, 30 Ill. 201. But this is not so in a life tenancy or estate. Taylor Land. & Ten., p. 81, § 70.