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.
The relation of the covenants depends in part on the question whether performance on the one side or the other requires only the doing of some continuous act, as for example the payment of money, or whether it requires the performance of a series of acts, such as a covenant for work and labor for a certain period of time. If performance on A's part must by its nature extend over a considerable period of time, while performance on B's part is instantaneous, such covenants can not be concurrent; and if they are dependent, one must be precedent either in whole or in part, and the other must be subsequent either in whole or in part.1 If A agrees to teach for a certain period of time and B agrees to pay therefor, the covenants can not be concurrent; and in the absence of some provision to the contrary, A's covenant will be precedent to B's.2 If A's covenant requires performance which extends over a period of time, and if B's covenant requires performance which extends over a period of time, the covenants may be dependent or independent, as the parties intend. If A's covenant is one which can be performed by doing an instantaneous act, and B's covenant is one which can be performed by doing an instantaneous act, the covenants may be independent or dependent, as the parties intend; and if dependent they may be precedent and subsequent on the one hand, or concurrent on the other, as the parties may intend.3
4 Leigh 21; Ayres v. Robins, 30 Gratt. 105; see note to Todd v. Summers (title 'Dependent Covenants'), Va. R. Anno. 322." Allemong v. Augusta National Bank, 103 Va. 243, 48 S. E. 807.
15 Rawson v. Johnson, 1 East 203; Ritchie v. Atkinson, 10 East 205; Morton v. Lamb, 7 T. R. 125; Measures Brothers, Ltd. v. Measures , 2 Ch. 248; Leonard v. Dyer, 26 Conn. 172; Statesville Flour Mills Co. v. Wayne Distributing Co., 171 N. Car. 708, 88 S. E. 771; Pacific Mill Co. v. Inman, 46 Or. 352, 114 Am. St. Rep. 873, 80 Pac. 424.
"Covenants are to be construed as dependent or independent according to the intention of the parties and the good sense of the case." Measures
Brothers, Ltd. v. Measuress , 2 Ch. 248.
"Whether covenants be or be not independent of each other must depend on the good sense of the case, and on the order in which the several things are to be done." Morton v. Lamb, 7 T. R. 125.
16 Gardiner v. Corson, 15 Mass. 500; Cunningham v. Morrell, 10 Johns. (N. Y.) 203, 6 Am. Dec. 332.
17 See Sec. 2037 and 2051.
18 Ink v. Rohrig, 23 S. D. 548, 122 N. W. 504.
19 Dermott v. Jones, 64 U. S. (23 How.) 220, 16 L. ed. 442.
20 Dermott v. Jones, 64 U. S. (23 How.) 220, 16 L. ed. 442.
1 Campbell v. Jones, 6 T. R. 570.