Columbus, in his letters to the sovereigns, enters into an account of the pecuniary advantage that will arise from these slave-dealing transactions, and from the sale of logwood.
He estimates, that "in the name of the sacred Trinity" there may be sent as many slaves as sale could be found for in Spain, and that the value of the slaves, for whom there would be a demand to the number of four thousand, as he calculated from certain information, and of the logwood, would amount to forty cuentos (i.e.forty million maravedis).

The number of slaves who were sent in these five ships was six hundred, of which two hundred were given to the masters of the vessels in payment of freight.

In the course of these letters, throughout which Columbus speaks after the fashion of a practised slave-dealer, he alludes to the intended adoption, on behalf of private individuals, of a system of exchange of slaves for goods wanted from the mother country.

The proposed arrangement was as follows:--The masters of vessels were to receive slaves from the colonists, were to carry them to Spain, and to pay for their maintenance during the voyage; they were then to allow the colonists so much money, payable at Seville, in proportion to the number of slaves brought over.
This money they would expend according to the orders of the colonists, who would thus be able to obtain such goods as they might stand in need of.

It was upon the same occasion of writing home to Spain that the admiral strongly urged upon the Catholic Sovereigns that the Spanish colonists should be allowed to make use of the services of the Indians for a year or two until the colony should be in a settled state, a proposal which he did not wait for their highnesses' authority to carry out, and which led to a new form of the repartimiento.