Yet these facts have little direct bearing upon the extent of the plantations themselves. The system of granting land, as we have seen, was not based upon the individual needs of the planters, but upon the number of headrights presented to the Government. Obviously it was the question of the most economical method of transporting immigrants which would determine the average size of the grant. If it proved best to bring in servants in small groups, distributed among vessels devoted chiefly to merchandise, the patents would be small; if they came in on immigrant vessels, in numbers ranging from 50 to 200, the patents would be large. Apparently both methods were in vogue. There are grants recorded varying in size from 50 acres to 10,000 acres.[3-22] Beyond doubt many merchants, finding that their vessels on the western voyage were not fully laden, from time to time took on a few indentured servants. If they furnished accommodation for from ten to twenty immigrants, they could demand, in addition to the sale of the indentures, 500 to 1,000 acres of land. It was a frequent practice, also, for planters in Virginia to send orders to their agents in England to procure and ship one or more servants as need for them arose.[3-23] "Your brother George hath moved you in his letters to send him over some servants the next year," wrote Richard Kemp to Robert Read in 1639.[3-24] Undoubtedly in cases of this kind the servants usually sailed in small parties upon the regular merchant vessels. On the other hand it would appear that large numbers of persons arrived on strictly immigrant vessels, in which they made the chief if not the only cargo. Some of the best known men in the colony were dealers in servants and reaped from the business very large profits. Of these perhaps the best known in the earlier period was William Claiborne, celebrated for his dispute with the Maryland proprietors over the possession of Kent Island. Peter Ashton was another extensive dealer in servants, at one time receiving 2,550 acres for his headrights, at another 2,000. Isaac Allerton, Lewis Burwell, Giles Brent, Joseph Bridger and many others of like prominence are upon the patent rolls for large grants. The most inveterate dealer in servants, however, was Robert Beverley. This well known planter, so famous for his part in Bacon's Rebellion and in the political contests which grew out of it, is credited with patents aggregating 25,000 or 30,000 acres.[3-25]