Granted he was ten.

“Passages from the Life of a Philosopher by Charles Babbage”, on Project Gutenberg is a collection of stories from Charles Babbage’s life that he says falls short of an autobiography. It’s really a fascinating book that’s much more readable then the title would suggest.

He talks about his childhood and how he tried summoning the devil:

[…] I resolved to attempt to raise the devil. Naughty people, I was told, had made written compacts with the devil, and had signed them with their names written in their own blood. These had become very rich and great men during their life, a fact which might be well known. But, after death, they were described as having suffered and continuing to suffer physical torments throughout eternity, another fact which, to my uninstructed mind, it seemed difficult to prove.

As I only desired an interview with the gentleman in black simply to convince my senses of his existence, I declined adopting the legal forms of a bond, and preferred one more resembling that of leaving a visiting card, when, if not at home, I might expect the sat­is­fac­tion of a return of the visit by the devil in person.

〈TRIES TO RAISE THE DEVIL.〉
Accordingly, having selected a promising locality, I went one evening towards dusk up into a deserted garret. Having closed the door, and I believe opened the window, I proceeded to cut my finger and draw a circle on the floor with the blood which flowed from the incision.

I then placed myself in the centre of the circle, and either said or read the Lord’s Prayer backwards. This I accomplished at first with some trepidation and in great fear towards the close of the scene. I then stood still in the centre of that magic and superstitious circle, looking with intense anxiety in all directions, especially at the window and at the chimney. Fortunately for myself, and for the reader also, if he is interested in this narrative, no owl or black cat or unlucky raven came into the room.

Young Charlie then tries to ascertain whether

all-merciful God could punish me, a poor little boy, with eternal torments because I had anxiously taken the only means I knew of to verify the truth or falsehood of the religion I had been taught

by conducting an experiment. Later, he makes a pact with a friend in which whoever dies first shall appear to the other to satisfy their curiosity.

You can read all about that on Project Gutenberg.