108. Wild Spirit?

Jan Baptista van Helmont, an early modern period Belgian chemist, is remembered today largely for his ideas on spontaneous generation, his 5-year tree experiment, and his introduction of the word "_______" into the vocabulary of scientists.
In one of his texts he writes:

"Suppose thou, that 62 pounds of Oaken coal, one pound of ashes is composed: Therefore the 61 remaining pounds are the "wild spirit" which, also being fired, cannot depart, the Vessel being shut. I call this spirit, unknown hitherto, the new name of '______,' which can neither be retained in Vessels nor reduced to a visible form, unless the seed is first extinguished."

The word was perhaps a Dutch pronunciation re-spelling of "chaos".

What word did Helmont coin?