With permission from the LABAC group's originator, Rob Smith, here is the advertisement showing Roy's sweet pea vase/compote, shown on page INT-10 of LABAC's Cut Glass Advertisements, book 2. In this case only a maker and country of origin can be ascertained, but without this one advertisement that important information would not be known. I've been a LABAC member about a year-and-a-half and I've lost track of the number of times this has happened.
About LABAC: LABAC is an informal nonprofit research group that pools resources to find and acquire significant Brilliant Period cut glass catalogs, booklets, photographs, scrapbooks, advertising and other materials. LABAC distributes copies of developed and found materials to members, for their personal study and research use. There are presently about nine dozen participants, and everyone is invited to join in this important research effort. Google "cut glass about LABAC" to learn more.