Non-performance of a condition which was possible at the time of its making, but which has since become impossible, is ex- cused if the impossibility is caused by act of God; Poll. Contr. 387; 10 Pick. 507; or by act of law, if it was lawful at its crea- tion; 16 Wall. 366; 1 Pa. 495; or by the act of the party; as, when the one impов- ing the obligation accepts another thing in satisfaction or renders the performance impossible by his own default; 21 Pick. 389; 1 Paine 652; 6 Pet. 745; 1 Cow. 339. If performance of one part becomes impos sible by act of God, the whole will, in gen- eral, be excused; 1 B. & P. 242; Cro. Eliz. 280; 5 Co. 21; 1 Ld. Raym. 279. The effect of conditions may be to suspend the obligation; as, if I bind myself to con- vey an estate to you on condition that you first pay one thousand dollars, in which case no obligation exists until the condi- tion is performed: or may be to rescind the obligation; as, if you agree to buy my house on condition that it is standing un- impaired on the tenth of May, or I convey to you my farm on condition that the con- veyance shall be void if I pay you one thousand dollars, in such cases the obliga- tion is rescinded by the non-performance of the condition: or it may modify the previous obligation; as if I bind myself to convey my farm to you on the payment of four thousand dollars if you pay in bank stock, or of five thousand if you pay in money: or, in case of gift or bequest, may qualify the gift or bequest as to amount of persons. The effect of a condition precedent is, when performed, to vest an estate, give rise to an obligation, or enlarge an estate already vested: 12 Barb. 440. Unless a condition precedent be performed, no estate will vest; and this even where the perform- mance is prevented by the act of God or of the law; Co. Litt. 42; 2 Bla. Com. 157; 4 Kent 125; 4 Jones, N. C. 249; 109 N. C. 461. Not so if prevented by the party imposing it; 13 B. Monr. 163; 2 Vt. 469. If a condition subsequent was void at its creation, or becomes impossible, unlawful, or in any way void, the estate or obligation remains intact and absolute; 2 Bla. Com. 157; 15 Ga. 103. Where the condition upon which an estate is to be divested and go to a third party is founded on a contin- gency that can never happen, the grantee will take a fee simple; 97 N. C. 206. In case of a condition broken, if the grantor is in possession, the estate revests at once; 5 Mass. 321; 5 S. & R. 375; 32 Me. 394; 63 Vt. 266; 129 Ind. 244; 1 Tex. Civ. App. 245. But see 2 N. H. 120. But if the grantor is out of possession, he must enter; 8 Blackf. 138; 12 Ired. 194; 18 Conn. 535; 8 Ν. Η. 477; 34 Me. 322; 8 Exch. 67; and is then in, as of his previous estate; Co. Litt. Butler's note, 94. Only the grant- or, his heirs or devisees, can take advan- tage of the failure to perform a condition subsequent, contained in a deed; 129 III. 466; 50 Ark. 141. It is usually said in the older books that a condition is not assignable, and that no one but the grantor and his heirs can take advantage of a breach; Gilbert, Ten. 26. Statutory have equal rights in this respect with common-law heirs; 18 Conn. 635; 25 Me. 625; and in some of the United States the common-law rule has been broken in upon, and the devisee may enter; 16 Pa. 150; 5 Pick. 528; contra, 20 Barb. 455; while in others even an assignment of the grantor's interest is held valid, if made after breach; 4 Harr. Del. 140; and of a particular estate; 19 N. Y. 100. In equity, a condition with a limitation over to a third person will be regarded as a trust, and, though the legal rights of the grantor and his heirs may not be destroyed, equity will follow him and compel a performance of the trust; Co. Litt. 236 a; 6 Pick. 306; 9 Watts 60; 2 Conn. 201. Consult Blackstone; Kent, Commentar ies; Crabb; Washburn; Real Prop.; Leake, Pollock, Contracts. As to effect of condi tions in deeds, see 9 Lawy. Rep. Ann. 165. Negative Condition. A condition which consists in not doing a thing; as, provided that the lessee shall not alien, etc.