The following is pieced from internet research:  “1847” and “IS” Marking on Rogers Brother Silver & Background
1847 Rogers Brothers Silver; this is the founding date of Rogers Brothers that they include in the hallmark of all their silverware and not the date of manufacture.  The “IS” stands for International Silver who has owned Rogers since 1898. The brand was first used in 1922, the Jubilee year for Rogers development of the process for electroplating silver onto base metal flatware and hollow ware in 1847.  For all American made silverware after 1890, if it’s not marked Sterling then it is silver plate.   Also, I have some of the original "Jewel Store" receipt cards that were given out when a customer purchased one of these rings. The sales tax is indicated as $0.05. I did a search of sales tax rates here in California and in Illinois (origin of Jewel stores) and a 5% tax rate appears to have been in the 80's.