Company Names, addresses, dates¹:
  Anton Danhakl, 124 N street NW (1904-1910)
  John Danhakl, Ky Ave c C Street SE (1894)
  John Danhakl, 1370 C street SE (1895-1907)
  John Danhakl, 1368 C street SE (1908-1913)
  John Danhakl, 1368 C street SE (1908-1913)
  Margarita Danhakl, 1368 C street SE (1913-1914)
  Joseph Danhakl, 2nd corner H NW (1890)
  Joseph Danhakl, 742 2nd street NW (1891-1896)
  Joseph Danhakl, 52 L street NW (1897-1914)

Notes:
A Descendent of the Danhakl family tells me there were 4 Danhakl brothers:

• Anton Danhakl (b. 1877 in Germany) came to America in 1885 according to the census. His name may have been Antone with an "e" at the end. He's listed in American Breweries II, and shows up in DC Directories as a brewer.
• John Danhakl (b. 1857 in Germany) came to America in 1885 according to the census. He is listed in DC directories as a Saloon keeper. Maybe Anton supplied him with beer? Margarita (Maggie) Danhakl was John's wife, and appears to have taken over his saloon in 1913. There is a bottle with her name (M Danhakl) on it².
• Joseph Danhakl (b. 1860 in Germany) is also listed as a saloon keeper in the directories.
  
• Sebastian Danhakl (b. 1859 in Germany) does not seem to have his name on any bottles.

(enlarge)	This is an 8.2" aqua blob top marked: front: A. DANHAKL / PHILA WEISS BEER / WASHINGTON, D.C. back: THIS BOTTLE / IS NEVER / SOLD
(enlarge)	This is an 7" aqua blob top marked: front: A. DANHAKL / PHILA WEISS BEER / WASHINGTON, D.C.
(enlarge)	This is an 8.7" clear blob top w/ stopper, marked: front: JOHN DANHAKL / 1368 C ST / SOUTHEAST / WASHINGTON, D.C. back: THIS BOTTLE / NOT TO BE SOLD