From the Wikipedia article on Great Illustrated Classics:
The Great Illustrated Classics series of books offers easy-to-read adaptations of well known classics, featuring large print and illustrations on every other page. The series is targeted at children, but the writing style is suitable for adult readers as well. Currently there are 66 titles.
Now I understand that they have to omit parts of the stories in order to fit them into this type of book. However, I don't see any reason why there would be a need to change things that are kept in the abridged versions. Yet in fact there are changes made in the abridged versions.
Here are three examples from The Count of Monte Cristo:
In the regular version it was Abbé Faria who directly showed Edmond that it was Danglars, Fernand, and Villefort that had caused his imprisonment. Yet in the Great Illustrated Classics version it is described as follows:
One day as Edmond and Faria rested from the hard work of tunneling, Edmond said, "Father, I have been thinking about my enemies. Your lessons on history have taught me how the minds of some men work in evil ways. I believe I was accused by two men — Danglars and Fernand.
In the next paragraph we have the following:
"Very good thinking," said Faria with a smile. "When you told me everything about yourself, I, too, suspected Danglars and Fernand. But I wanted you to puzzle it out."
This seems to be a complete invention.
In the original version the value of Spada's treasure is specified as 13 or 14 million Francs. In the Great Illustrated Classics version the value is given as 70 million Francs.
In the original version the cannon signifying an escaped prisoner goes off well after Edmond boards the smugglers' boat. In the Great Illustrated Classics version, however, the cannon is shot before he even sees their boat.
Here are two examples from A Journey to the Center of the Earth:
At the end of the book when they get shot out of a volcano and wonder where they are, Hans says that they are not in Iceland. In the original version, the narrator says that Hans is wrong:
"Hans must be mistaken," I said, raising myself up.
In the Great Illustrated Classics version it is the narrator's uncle who asserts that Hans is wrong:
"You must be wrong," my uncle cried.
The date that they leave Stromboli is off by a month. In the original version we have:
After waiting forty-eight hours, on the 31st of August, a small craft took us to Messina, where a few days' rest completely removed the effect of our fatigues.
In the Great Literary Classics version we have:
And forty-eight hours later, on the 30th of September, a boat took us to the city of Messina on Sicily.
There are many more examples, but I don't think it is necessary to list them.
Is there a purpose to these changes? Do they somehow simplify the story for children? Or did the adapters just read the originals and then entirely rewrite the books as simply stories based on the original?
I am primarily interested in a general principle (or set of principles) that addresses the series as a whole. However, if the answer is that each individual change has its own reason, I am okay with that but would ideally like to see one or two example explanations of some of the individual cases (not necessarily limited to the ones I mentioned).