This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
If, from its nature, performance is or may be instantaneous on each side, as in the case of a sale of realty which is to be conveyed by one deed, and for which the purchaser is to make a single payment,1 or in the case of the sale of goods which are to be delivered at the same time and for which the purchaser is to make a single payment,2 the covenants on each side are presumed to be concurrent3 if they go to the entire consideration on each side 4 and if there is nothing in the contract which shows an intention that either party shall give credit to the other.5 A different question arises in cases in which performance on the one side is not an instantaneous act, either by reason of the agreement of the parties or from the nature of the performance. In cases of this sort performance on one side must be precedent to performance by the other, either in whole or in part; 6 but in such cases the performance of the last instalment, or of the whole of the continuous act, is generally regarded as concurrent with the duty of the adversary party to perform on his side.7 In such case the party who is to perforin in instalments can not require the adversary party to divide performance on his part into corresponding instalments, if the contract has not made such provision.8 Under a contract for the sale of goods, which makes no provision for payment in instalments, the seller can not require the buyer to pay for the instalments as they are delivered.9 Whether delay in performing the instalments, which are precedent covenants, until performance of the last instalment, which is concurrent with performance by the adversary party, converts the precedent covenants into concurrent covenants, is a question upon which there is a conflict of authority - some jurisdictions taking the position that under such circumstances all the covenants on one side, whether precedent or concurrent, become concurrent with the covenant on the other side, which originally was concurrent with the covenant for performance of the last instalment;10 while in other jurisdictions it is held that such delay in performance does not affect the relation of the covenants, and that the covenants which were originally precedent remain precedent.11 This question frequently arises in contracts by which the purchaser is to pay for land in instalments and the vendor is to convey upon payment of the last instalment, or at least upon payment of some instalment after the first, and the purchaser has delayed his payments until the time which is fixed by the contract for paying the instalment which is concurrent with the duty of the vendor to convey the realty. In some jurisdictions it is held that under the circumstances the duty of the purchaser to pay all the instalments is concurrent with the duty of the vendor to convey the realty, and that the vendor can not recover any of the instalments unless he is ready and willing to convey and calls upon the purchaser to perform;12 while in other jurisdictions it is held that the covenants which originally were precedent remain precedent.13
6 Loud v. Pomona Land & Water Co., 153 U. 6. 564, 38 L. ed. 822; Hill v. Fisher, 34 Me. 143; Kirtz v. Peck, 113 N. Y. 222; 21 N. E. 130; Gale v. Best, 20 Wis. 44.
7 Hill v. Grigsby, 35 Cal. 656.
8 Glenn v. Rochester, 156 N. Y. 161, 50 N. E. 785.
9 Bohall v. Diller, 41 Cal. 532.
10 Hill v. Grigsby, 35 Cal. 656.
11 Ink v. Rohrig, 23 S. D. 548, 122 N. W. 504.
1 See Sec. 2964.
2 See Sec. 2065. 3 See Sec. 2062.
4 See Sec. 2062 and 2074. 5 See Sec. 2951 et seq. 6 See Sec. 2051 et seq.
7 United States. In re Hellams, 223 Fed. 460.
California. Hill v. Grigsby, 35 Cal. 656.
Indiana. Irwin v. Lee, 34 Ind. 310.
Kansas. Soper v. Gabe, 55 Kan. 646, 41 Pac. 960.
Michigan. Pearce v. Alward, 163 Mich. 313, 128 N. W. 210.
Hew Jersey. Kelly Construction Co. v. Hackensack Brick Co., 91 N. J. L. 585, 2 A. L. R. 685, 103 Atl. 417.
New York. Beecher v. Conradt, 13 N. Y. 108; Eddy v. Davis, 116 N. Y. 247.
8 In re Hellams, 223 Fed. 460; Kelly Construction Co. v. Hackensack Brick Co., 01 N. J. L. 585, 2 A. L. R. 685, 103 Atl. 417.
9 In re Hellams, 223 Fed. 460; Kelly Construction Co. v. Hackensack Brick Co., 91 N. J. L. 585, 2 A. L. R. 685, 103 Atl. 417.
10 Hill v. Grigsby, 35 CaL 656; Irwin v. Lee, 34 Ind. 310; Soper v. Gabe, 55 Kan. 646, 41 Pac. 969; Beecher v. Conradt, 13 N. Y. 108; Eddy v. Davis, 116 N. Y. 247.
11 Sheeren v. Moses, 84 Ill. 448; Bowen v. Bailey, 42 Miss 405.
If performance is to be continuous on both sides, it may be so far concurrent that breach by either party may operate as a discharge of the adversary party.14 Under a contract for the sale of land, which requires the vendor to replace trees or vines within a certain period of time, such covenant is concurrent with the duty of the adversary party to perform; and a breach of such covenant on the part of the vendor may be treated by the purchaser as a discharge of the contract.15 Under a contract by which A is to take possession of B's mine and operate it and deposit the proceeds in a given bank to B's credit, A's duty to perform is concurrent with B's duty to allow A to remain in possession of B's mine; and A's act in depositing such proceeds in another bank to his own credit operates as a discharge of B's covenant.16 Under a marriage separation contract, the wrongful act of the wife in committing adultery discharges the husband from his duty to make further payments.17