"Your Highness, that copper tube you're holding—why is one end big and the other small, and so bright and clear...?"
"Oh! Black Wolf, this is the Institute of Divine Inspiration's latest masterpiece, the 'Divine Eye Telescope'! It can magnify distant scenery several times over, as if it were right before your eyes!"
On the little hill by the sea, Xolotl smiled as he handed the copper tube in his hands, a full meter long, to Black Wolf Toltec.
"Come! You take a look too!"
"Ah! Divine Eye Telescope? A new... divine instrument from the Institute of Divine Inspiration?"
Toltec drew in a deep breath and carefully took the long tube. He cautiously reached out, touching the two convex, transparent crystals at either end of the tube—one large, one small—as if he were touching some wondrous object that possessed mysterious power.
"Oh! Black Wolf, these two transparent convex lenses were both carefully polished from natural, clear crystal by the jade artisans of the Institute of Divine Inspiration! The larger one is the 'objective lens,' facing the object outside. The smaller one is the 'eyepiece,' facing the eye..."
"And the magnification is the focal length of the objective lens divided by the focal length of the eyepiece. As for the specific principles behind it, including convex lenses, concave lenses, focal length, light rays, and real and virtual images... I wrote a new little book called Introduction to Divine Optics. If you're interested, you can go learn a thing or two..."
Xolotl explained carefully for a while, then looked at Black Wolf's bewildered eyes and his arm, which had suddenly started trembling. He could not help laughing and shaking his head, then patted his beloved general on the shoulder.
"Haaha! Forget it. You don't need to study the specific optics... Mm! Black Wolf,