Which preposition to use with hardiness

of Occurrences 5%

Trials for the special purpose of testing the hardiness of the more tender kinds have been instituted and carried out in several favoured parts of England and Ireland.

in Occurrences 1%

There are, however, three respects in which his education seems especially worthy of notice;I mean the diligence, the gratitude, and the hardiness in which he was encouraged by others, and which he practised with all the ardour of generous conviction.

Which preposition to use with  hardiness