Definition of "indagation"

Part hereof hath been discovered by himself, and some by humane indagation: which though magnified as fresh inventions unto us, are stale unto his cognition.

1646, Thomas Browne, chapter I, in Pseudodoxia Epidemica: […], London: […] T[homas] H[arper] for Edward Dod, […], 1st book, page 10

[T]his brief Inventory I have here given as preparatory to vvhat follovvs, and to pre-poſſeſs the Reader, 1. That a natural Indagation according to the light of natural Reaſon touching the Origination of ſuch a Creature as this, is no contemptible or unvvorthy enquiry.

a. 1677 (date written), Matthew Hale, “Touching the Excellency of the Humane Nature in General”, in The Primitive Origination of Mankind, Considered and Examined According to the Light of Nature, London: […] William Godbid, for William Shrowsbery, […], published 1677, section I, page 69