Vintage cobalt blue 14 oz bottle
The M inside a circle is the maker's mark for the Maryland Glass Company.The number 13 is a mold number.The bottle was likely machine-made between 1921 and later.Maryland Glass Company produced bottles for various products, including Bromo-Seltzer and Phillips' Milk of Magnesia.The bottle is cobalt blue in color.The size is approximately 7 1/2 inches tall.The bottle likely held 14oz.