Rhode Island Stampless Covers & Letters
Reverse of 1771 Nicholas Brown and Company Cover
Showing the Franklin Mark and Philadelphia Straight Line Cancel
Return to 1771 Cover and Background History

See below links for further information: 
The History of Brown and Ives with Brown family Genealogy 
1789 Brown and Benson Letter from Champion and Dickason - London 
1834 Brown & Ives Letter from Amsterdam Factor 
1852 Brown & Ives Letter from Baring Brothers - London, England 

Sources:
Off Soundings - Aspects of the Maritime History of Rhode Island by Alexander Boyd Hawes
Rhode Island Genealogy and History Project 
The Providence Plantations for 250 Years - by Welcome Arnold Greene - 1886
American Stampless Cover Catalog, Volume I