Before trolling through a 1910 edition of the Encyclopedia Britannica, I would not have been able to tell you what this scientific instrument was called. Now, I know that this is an armillary sphere drawing.
Armillary spheres are used in astronomy. The depict a model of objects in the sky. There are two kinds – Ptolemaic , earth-centered and Copernican, or sun-centered. Our armillary sphere drawing is an Earth-centered model.
Armillarys originated in China. Ptolemy describes using a similar device. This armillary sphere drawing is identified as being an instrument from 1636.
There’s a whole lot of science involved in how to use them. But, for our uses, it’s just a cool piece of scientific equipment.
This image is copyright free and in the public domain anywhere that extends copyrights 70 years after death or at least 120 years after publication when the original illustrator is unknown.
