Unless otherwise agreed all goods called for by a contract for sale must be tendered in a single delivery, and payment is due only on such tender; but where the circumstances give either party the right to make or demand delivery in lots, the price, if it can be apportioned, may be demanded for each lot.
Source: L. 65: p. 1308, � 1. C.R.S. 1963: � 155-2-307.