What does "rochelle" mean?

Rochelle: A seaport town in France. Rochelle powders. Same as Seidlitz powders. -- Rochelle salt (Chem.), the double tartrate of sodium and potassium, a white crystalline substance. It has a cooling, saline, slightly bitter taste and is employed as a mild purgative. It was discovered by Seignette, an apothecary of Rochelle, and is called also Seignete's salt.