M inside a circle: Maryland Glass Corporation

Maryland Glass Corporation

Baltimore, Maryland   


“M inside a circle” marking 

This mark was first used in 1921, according to trademark information reported in Arthur G. Peterson’s  400 Trademarks on Glass  (1968).  However, Julian Toulouse, in Bottle Makers and their Marks (1971, page 341) writes that the “M in a circle” first appeared on bottles in 1916.

Maryland Glass Corporation was organized in 1907 as a vehicle for making large quantities of Bromo-Seltzer bottles for parent Emerson Drug Company, of Baltimore.   Emerson Drug Company (founder and president, Issac E. Emerson) had been incorporated in 1891, and because of increasing sales needed a reliable source of supply for the large quantities of glass bottles needed.

This company was soon specializing in producing all kinds of cobalt blue bottles and jars.  Many of the containers made for Phillips Milk of Magnesia, Bromo-Seltzer,  Bromo-Caffeine,  Vicks Vapo-Rub,  Noxema, and others were produced here.   Maryland also produced clear glass as well as cobalt.

The “M in a circle” mark is seen on tremendous numbers of glass containers from the 1920s through the 1960s, and cobalt blue jars and bottles from trash dumps of this time period are often found that bear this mark.  Many of these containers have no identification or brand markings other than the “M in a circle” on the base.

Maryland produced the most commonly-seen type of figural “violin bottle” or “fiddle bottle”  in various shades of blue (and probably other colors) although these bottles were not usually marked.  They may bear a mold number on the bottom.

3 Maryland Glass Corporation bottles in cobalt

Maryland Glass Corporation bottles: (Left to right) marked “Phillips Milk of Magnesia Tablets” with an “M”; Bromo-Seltzer Emerson Drug Co. bottle with “M in a circle / 24″ on base; plain blue medicine/chemical bottle with “M in a circle / 7″ on base.

Maryland Glass was acquired by the Dorsey Corporation in 1968, and I believe that the “M” mark was used for a time thereafter, but eventually discontinued sometime in the early 1970s.  Anyone with more concrete info,  please contact me on how late this mark was actually used, and I will be happy to add the data to this page, with credit to the contributor!

M in a circle bottle base

“M in a circle / 7″ Base of plain bottle pictured on right in group photo.

Bromo Seltzer bottle base

Bromo Seltzer bottle base

Phillips Milk of Magnesia Tablets bottle base

Phillips Milk of Magnesia Tablets bottle base


Maryland also used the “plain M” on some bottles, and rarely, an “M inside a G”, which are listed on the Glass Bottle Marks pages, page 4.

NOTE: The “M in a circle” is also seen on the base of tableware, novelty glass shoes, upscale reproduction pattern glass, various colored glass toothpick holders, etc, and in those cases it is the mark of the Mosser Glass Company, of Cambridge, Ohio.  (Maryland Glass made, for the most part, utilitarian and commercial containers.) 


Click here to go to the Glass Bottle Marks pages (page 4).

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3 Responses to M inside a circle: Maryland Glass Corporation

  1. jim Coyle says:

    Among the specialty bottles they made was a very unique cigarette holder; it was a blue jar, similar in size to a Noxema jar, with a fish, crab and lobster embedded in the glass. It also had a divider with a silver top to hold the cigarettes. If anyone has seen such an item, I would be pleased to know.

    • Ken Huffman says:

      My grandpa worked at Maryland Glass for 50 years, also his sons and daughters were lifelong employees. When I was a child, I helped Pappy build machines in the extra bedroom which he gave to to company and significantly increased quality and production. My grandfathers name was Charles Henry Knickmen. TY. Ken Huffman 540-718-8111

      • David says:

        Hi Ken, and thank you for the information! I’m posting this on the page, so perhaps others with a family history relating to Maryland Glass could contact you. ~David