How to change number of items per page, in a category?

There is likely a simple answer to this question.
How do I modify the number of items viewed in a given category?
I have a couple of categories that show a long list of items that are in that category while other categories only show 1 item per page. I have not been able to find the setting that would control this function. :S
google translation to french J'ai quelques catégories qui montrent une longue liste d'articles qui sont dans cette catégorie, tandis que d'autres catégories montrent seulement 1 point par page . Je ne suis pas en mesure de trouver le réglage qui permettrait de contrôler cette fonction .
I am using the most recent version of FC and Joomla
Thanks for the appropriate directions.

Hi,
category settings - item lists - Limit / suppress items
Leading items can be set in category settings - Layout - Layout parameters
Please check, if your muni item settings override this!
Rooney

knew it was something simple - just couldn't see it...