1892 Map of Charles River showing principal sources of pollution by the Boston Engineering Dept, from the Digital Commonwealth - commonwealth 3f4635739. (<a rel="nofollow" class="external free" href="https://www.digitalcommonwealth.org/search/commonwealth:3f4635739">https://www.digitalcommonwealth.org/search/commonwealth:3f4635739</a>)
Boston Engineering Dept
Digital Commonwealth