I do believe this is the most beautiful advertising trade card I have ever seen-- combining perhaps the best company logo ever with the perfect graphic design (that lettering!) and beautiful production (that gold!). I have only found one other like this, held in the San Diego State University Library Special Collections; it's a rare one. And dates to the late 19th century, as soon after Arm and Hammer changed the name from Salerutus to the perhaps catchier Baking Soda!
5 1/8" x 3 7/8" and in very good condition, with a little wear around the edges and some old glue marks on the reverse side, which sings the praises of the product, and Dr. Austin Church of Church & Co. (with an office on Pearl Street in Manhattan an d factory in Greenpoint, Brooklyn) who created it.