RARE Jelly-quick ANTIQUE advertising saucer plate Gelatin Dresden semi-porcelain

These aren't perfect!! Small, 5" across. EIGHT in all--- 3 have chips, 2 have some stains, they may have age crazing--one more then others(shown). Please see pictures.  I can't find anything else like them--I assume the "Jelly-quick" is a type of gelatin for making jelly or jello?  They may even date back to Victorian, according to mark, but not sure of exact time frame. 

I have lots of antiques!