’So deep,’ replied his young friend, ’that even I can’t fathom it.
Tantalised and excited, beyond all bearing, and unable to fathom the mystery without neglecting his duty, he confided the whole secret to Newman Noggs, imploring him to be on the watch next night; to follow the girl home; to set on foot such inquiries relative to the name, condition, and history of her mistress, as he could, without exciting suspicion; and to report the result to him with the least possible delay.
There are no more uses of "fathom" in the book.
Show samples from other sources
When I look at the shift my life has made in the past eight months, I can’t fathom what my life will be eight months from now.
Colleen Hoover -- Slammed
He couldn’t fathom why WICKED felt it was so important to keep their minds clean of memory.