Translations for invincible in French

Here are paragraphs from public domain books translated:

It was at such a moment that I learned the stuff of which my three comrades were composed. They were grave, it is true, and thoughtful, but of an invincible serenity. For the moment we could only sit among the bushes in patience and wait the coming of Zambo. Presently his honest black face topped the rocks and his Herculean figure emerged upon the top of the pinnacle.	C’est dans un moment pareil que je jugeai vraiment de quelle étoffe étaient faits mes trois camarades. Graves, sans doute, et pensifs, ils gardaient une sérénité invincible. Nous ne pouvions faire mieux qu’attendre patiemment, assis dans la broussaille, l’arrivée de Zambo à la pointe de l’aiguille. Enfin, son honnête figure d’hercule noir émergea d’entre les rocs
The Lost World, by Arthur Conan Doyle	Le Monde perdu, de Arthur Conan Doyle

It was at such a moment that I learned the stuff of which my three comrades were composed. They were grave, it is true, and thoughtful, but of an invincible serenity. For the moment we could only sit among the bushes in patience and wait the coming of Zambo. Presently his honest black face topped the rocks and his Herculean figure emerged upon the top of the pinnacle.	C’est dans un moment pareil que je jugeai vraiment de quelle étoffe étaient faits mes trois camarades. Graves, sans doute, et pensifs, ils gardaient une sérénité invincible. Nous ne pouvions faire mieux qu’attendre patiemment, assis dans la broussaille, l’arrivée de Zambo à la pointe de l’aiguille. Enfin, son honnête figure d’hercule noir émergea d’entre les rocs
The Lost World, by Arthur Conan Doyle	Le Monde perdu, de Arthur Conan Doyle