Below are a small number of websites dealing with historical aspects of Boston -- life, architecture, culture etc. Though most of these websites are not specifically concerned with the 19th century history of Boston, it is worthwhile browsing through them for potentially useful material. Many other relevant websites may be located by appropriate web searching.
"View of the Water Celebration, on Boston Common, October 25th 1848." Lithograph by P. Hyman and David Bigelow.