Company Names, addresses, dates¹:
  Roberts Manufacturing Co, 408 Princess, Alexandria (1924-1930)
  Roberts Manufacturing Co, 109 King, Alexandria (1932-1938+)

Notes:
The Roberts Manufacturing Co was at 408 Princess street, the same address as the former Rammel Mfg Co. I'm not sure if the Roberts and Rammel companies were somehow connected.
Roberts Mfg Co was listed in the 1928 "Business, Manufacturers Merchants and Tradesman Financial condition for Alexandria VA" as having an estimated Pecuniary Rating of $3000-$5000.

Bottles:

(enlarge)	This is an 8" clear crown top bottle marked: front: Roberts Mfg. Co. / 7 FLUID OZS back: Alexandria, Va. / 25 B6 bottom: R
(enlarge)	This is a 9" clear crown top bottle marked: front: ROYAL TREAT / TRADE MARK / ROBERTS MFG CO back: ROYAL TREAT / REGISTERED / ALEXANDRIA, VA. bottom: CONTENTS 7 FLU OZS