Company Names, addresses, dates¹:
  Roberts Manufacturing Co, 408 Princess, Alexandria (1924-1930)
  Roberts Manufacturing Co, 109 King, Alexandria (1932-1956)

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.
A 1947 phone book has 2 entries for Roberts Manufacturing Co, the 2nd one saying "Dixie Cola / Roberts Manufacturing Co.
The Frostie Bottling Company was at the same address (109 King Street) starting in 1958.

Bottles:

	book # 584 This is an 8" clear crown top bottle embossed: front: Roberts Mfg. Co. / 7 FLUID OZS back: Alexandria, Va. / 25 B6 base: R
	book # 618 This is a 9" clear crown top bottle embossed: front: ROYAL TREAT / TRADE MARK / ROBERTS MFG CO back: ROYAL TREAT / REGISTERED / ALEXANDRIA, VA. base: CONTENTS 7 FLU OZS
	book # (unlisted) This is an 11.5" green crown top bottle embossed: front shoulder in fancy border: ROYAL TREAT front heel: ROBERTS MFG. COMPANY rear shoulder: FULL QUART 30 OZ. rear heel: ALEXANDRIA, VA. base: N 43 3

	This is a bottle red, white & silver bottle cap. It says: front: ROBERTS / STRAWBERRY / ARTIFICIAL FLAVOR & COLOR edges: ROBERTS MF'G CO. ALEXANDRIA, VA. CCSI
	This is a 6"x12"x18.5" wooden crate that holds 24 bottles. It is marked: ends, in black: ("MADE BY ACME BOX CO BALTO MD" in circle) / 4 46 / ROBERTS / MANUFACTURING CO. / ALEXANDRIA VIRGINIA sides, in red: ROYAL TREAT / BEVERAGES / ROBERTS MANUFACTURING CO. I suspect the '46' indicates it was from 1946.
	This is a modern photo (taken July 2010) of 109 King Street, which used to house the Roberts Manufacturing Company. 109 King is on the left side, where the POPS ICE CREAM sign is.