1871 Map showing the telegraph lines in operation, under contract, and contemplated, to complete the circuit of the globe, by J. H. Colton &amp; Co, G. W. &amp; C. B. Colton &amp; Co, from the Digital Commonwealth - commonwealth 7h149w171. (<a rel="nofollow" class="external free" href="https://www.digitalcommonwealth.org/search/commonwealth:7h149w171">https://www.digitalcommonwealth.org/search/commonwealth:7h149w171</a>)
J. H. Colton &amp; Co, G. W. &amp; C. B. Colton &amp; Co
Digital Commonwealth