family portraits etched on glass

My client has colonial pictures of his ancestors etched on glass. They are in a leather bond frame about the size 2 by 4 frame and some are oval shaped. Also some small albums and the pictures are about one inch by 2 unches high. Never seen anything like thes before. He is 92 and it is pictures of his mothers parents. I would send pics of them but he had a hot water heater to burst and had to send them out to be cleaned. Was wondering if anyone has ever seen any of these

Sami