What armour protected the Pearl class?

What armour protection did the Pearl-class cruisers carry?

The drawing may show a sloped protective deck, about two inches on the slopes and one inch on top, although the material could be ordinary steel rather than armour.

This specification question receives a cautious answer because no clear armour reference for the Pearl class had been found. The drawing may show a protective deck over the machinery with about two inches on the slopes and one inch across the top. The material might also be ordinary fixed steel rather than armour, so the figures remain provisional.