The 1887 and later Hopkins atlases are offline currently (they are not available through Library of Congress–which has the Baist atlases)–as per:

There is new Dig DC! All the collections you know and love will be available soon; please bear with us as we migrate them. In the meantime, if you’re looking for a photograph, oral history, map, or newspaper that isn’t here yet, please email us at wash.dcpl@dc.gov.

There is an alternative for the 1887 (and 1894 v.3) Hopkins atlas–DCRA’s Surdocs system:

 

https://dcra.dc.gov/page/surveyor-documents-surdocs

Navigate in. Log in (credentials are posted on the screen).

• Then choose: Search by book and page
• The choose: Miscellaneous books
• Then choose: Hopkins_1887 (or Hopkins_No_3_1894)
• Click: Select page
• Choose the appropriate page or the index
• Click: View image

It is not especially easy to navigate but there are lots of helpful documents on the website.

UPDATE; 1887 Hopkins online once again