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 blue glass containers made for Phillips Milk of Magnesia, Bromo-Seltzer,  Bromo-Caffeine,  Vicks Vapo-Rub,  Noxzema, and other products 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, with “M” for Maryland Glass.


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

NOTE: An “M in a circle” logo 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 an unrelated firm, 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 (page 4).

Click here to go to my Home Page.

32 Responses to M inside a circle: Maryland Glass Corporation

  1. Jim Coyle says:

    Thanks for clarification.

  2. Jim coyle says:

    Looks like David has given you what you needed. There was a period in the early 1900’s when the MD Blue Glass did not have the “M” on them. So it makes it difficult to clearly identify every cobalt blue glass item as MD Glass. I have been researching to see if someone wrote a catalogue on all the MD Glas products; unfortunately I have not found this.

    My father worked there from 1929 to 1969; his entire career.


  3. Joseph Haley says:

    My son just gifted me a cobalt blue MG Co. bottle. I understand the circle M mark, but I have questions about the other marks. Over the ‘M’ the letter ‘L’. Under the ‘M’ is ‘Design PA’ (the D looks more like an ‘O’,but that doesn’t seem to fit, and I can not find a Design PA on the map so far. Under this mark are the numbers ‘97178’, and under that the number ‘5’. I assume the 5 is a mold mark.
    Joseph Haley
    Tallahassee FL

    • David says:

      Hi Joseph,
      Not sure about the “L”. but the other markings mean “DESIGN PATENTED” (by the United States Patent and Trademark Office) and the patent number of that particular bottle design which is D97178. I searched the “Google Patents” site and found this: (The bottle design was patented in 1935). https://patents.google.com/patent/USD97178S/en. Hope this helps!

  4. Glen Mullins says:

    I have pictures of some products,I have of Md.Glass, cobalt blue,if anyone is interested I can be reached at. glenfromberlin1934@hotmail.com

    • Jim coyle says:

      Thanks for your note. Glad you have an interest in the Md. Glass Corp materials. I have collected most of the various bottles they made; my focus is on the specialty items they made which were given as gifts to customers and friends.

      Jim coyle

  5. Diane says:

    does anyone know of a site i can go on that I can look up pieces? I have a set of ruby footed cut glasses and I’m trying to find out the name of them. I took a book out of the library titled “GLASS OF CUMBERLAND MARYLAND AREA” by Dale Murschell. They were in there, thats how I know they are by Maryland Glass, but there wasn’t any style name. Please email me at Dianevgi@aol.com if you know where I can find these. I usually don’t go on the internet so much, so I probably won’t go on this site again, so an email would be great. Thank you for any help you can give me.

    • David says:

      Hi Diane, I am posting your query here. Perhaps a reader will contact you with more information. I tried to find Dale L. Murschell’s current contact information online without success. There is someone by that name who lives in West Virginia but it may not be the same person.
      I am sure the ruby footed glasses you refer to were not made by Maryland Glass Corporation. I do not have a copy of Murschell’s book; however, from my understanding, his book concentrates on glass factories located in the Cumberland, Maryland area (Allegany County). Maryland Glass Corporation (subject of this webpage) was located in Baltimore (Baltimore County). The Maryland Glass Company of Cumberland, Maryland was unrelated to Maryland Glass Corporation of Baltimore. Maryland Glass Corporation made primarily (not exclusively) container glass. Maryland Glass COMPANY of Cumberland apparently made tableware, not bottles.
      Best regards,

      • Diane says:

        David…thank you….I guess I will have to go back to the library and check other books for these glasses 🙂

        • David says:

          Hi Diane, just to make sure I’m making myself clear………….if those exact glasses ARE illustrated in Dale Murschell’s book on the glass of Cumberland, Maryland, then I would suggest you just need to contact Mr. Murschell and see if he has any more info about the pattern name, values, etc. (As far as I know he is still alive, but I don’t know that for sure.) I strongly doubt you will find the glasses shown in any other books. Would you be able to email me a pic of the glasses? Please send to my email address which is listed at the bottom right-hand corner of any page on this website.
          Best regards, David

  6. Jim Coyle says:

    Thanks for the technical info about 1921. That helps with identifying pieces after that.

  7. Jim coyle says:

    My father got a chemistry degree from Loyola College in 1929. He went to work at MD. Glass as a chemist. A fellow Loyola classmate was the son of the Corp. President, Phil Heisler. he worked there til his death in 1969, rising to the position of Superintendent of Glassmaking.

    the M on the products came about around 1930. But not all products had the symbol on them. many of their gift items were unique and not produced in large quantities. I think there most famous gift was the blue glass violin bud vase. I have been attempting to collect these gift items over the years. at the Bottle Club exhibition this past Spring, I found an item I was not aware of made in the early 1930’s. It is a blue glass ashtray with the Md Glass name and M on the bottom and identified as a Christmas gift. It looks like a flat tea bag holder with a Ladle handle. It was dated 1934.

    I have been searching for the blue glass piggy banks that they produced in the late 1940’s into the 50’s. Since they did not have an escape hatch, they likely were broken to retrieve the coins.

    I wish that someone had catalogued all of their products from the beginning of the seltzer bottles.


    • David says:

      Jim, the cobalt blue glass piggy banks sound beautiful and adorable, and I would guess that occasionally one of them shows up on ebay! I’m sure a few people kept them as keepsakes, or for decoration and didn’t store coins in them, and so never felt the need to break them! At least I certainly hope so!!! Also, I’m not trying to pick an argument with you, but according to Arthur G. Peterson’s reference book “400 Trademarks on Glass” (1968) the “M inside a circle” was used beginning in 1921. His information came from researching the actual United States Patent & Trademark Office records, so I assume it is correct (or at least, that is assumedly the information that was supplied to the government office by Maryland Glass Company when applying to have their trademark officially registered).
      Best regards,

  8. Jack Burkert says:

    Hello to all you “posters” – I sent this to Jim initially, but realized many of you may have stories to tell or things to share. I work for the Baltimore Museum of Industry. I am unofficial in asking, but could you relate the “story” of Maryland Glass for me sometime? I would love to take notes. Do you have an “artifacts”? Many thanks, Jack Burkert – burkert.jack@gmail.com

  9. Jim Coyle says:

    That is great! Maybe someone could start a MD. Glass Corp. Alumni group. It could be a subset of the Baltimore Bottle Club.

    I am surprised by how little has been researched and written about the MD. Glass Corp since it was a major company in Baltimore for 70 years. For example, I can’t find a written catalog of all the products and gifts they made all those years. My knowledge is from my memory as a son of a 40 year employee.


    • Jack Burkert says:

      Jim, I work for the Baltimore Museum of Industry. I am unofficial in asking, but could you relate the “story” of Maryland Glass for me sometime? I would love to take notes. Do you have an “artifacts”? Many thanks, Jack Burkert – burkert.jack@gmail.com

  10. Wanda Knickman Barthel says:

    My Pappy, Charles Knickman, his sons, my father Maynard Knickman, and my uncle Sonny Knickman worked at Maryland Glass all their lives. I still have some pieces my Dad brought home. A colbalt blue top hat, a ringed vase and a violin. At my childhood home in Elkridge we had one of the machines Pappy made. I don’t know what happened to it. I do have a copy of the blue prints. I believe Pappy was a glassblower in his early years.

  11. Jim coyle says:

    My father, Thomas Coyle, worked there for over 40 years, ending as Superintendent of glassmaking. Do you know where any others of the cigarette jars may be available for purchase? secondly, did anyone ever catalogue all the various bottles and jars that the company made over the years?
    I wish there were a more documented history of the MD Glass Co.


  12. Glen Mullins says:

    I worked for me. Glass corp for22 yrs.i had the cigarette holder you speak of,in addition to the fish and crabs it also has Maryland my Maryland on it. On the bottom it has Christmas 1932. I was a mold maker there, my son now has the cigarette, humidor,. My name is Glen Mullins

  13. Randall hughes says:

    I am inquiring to see if anyone knows what the #s under the M trademark stumble stand for?

    • David says:

      Randall, usually, the single or double-digit numbers along with the “M in a circle” trademark are mold numbers— identifying the mold which was used to make the item.

  14. 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

    • Glen Mullins says:

      Jim my name is Glen Mullins. I was a mold maker at md.glass corp. for 22 yrs,I had the cigarette humidor you speak of.my son has it now.i could probably send you a picture of it.

      • David says:

        Please let me chime in as well………..if you see any info here on my site that you believe is in error, please feel free to contact me. I would like to have my webpage on Maryland Glass (as well as my pages on other glass companies and topics) as accurate as possible. I realize there is ALOT that is not known, or at least is not published, about glass and glass companies, so bottle researchers just go by the best info available. Take care and thanks for your input.

      • Jim Coyle says:

        That would be great for my records. Thanks.