Anne,

I believe the letters embossed on the base of your bottle are actually "NYQ&CWLTD" and are the abbreviation for the New York Quinine and Chemical Works, Ltd.  The company manufactured chemicals, and was a leading manufacturer of quinine and also was a source (legal) for morphine, cocaine, codeine, strychnine, acetanilide, etc.  This New York City firm was a subsidiary of a larger pharmaceutical manufacturer, McKessin and Robbins.  I don't know when the company began operations, but I have a copy of a 1913 advertisement & I know they were still operating in 1953.  The Lloyd Library in Cincinnati has a file of the company's price lists & could probably provide dating information (Box 63, Folders 1-23).  The relatively wide mouth in a pharmaceutical bottle is consistent with a solid rather than a liquid product. Hope this is helpful.

Allen