Christiani Hugenii Zelemii, dum viveret, toparchae opuscula postuma, quae continent dioptricam. Commentarios de vitris figurandis. Dissertationem de corona & parheliis. Tractatum de motu. De vi centrifuga. Descriptionem automati planetarii

which we shall teach in its proper place. We have, however, taken care to include those words, even though they were deleted by the Author, since our author attached so much importance to that amount of aberration of the machine from the Heavens within 20 years that he wished for them to be engraved upon the machine itself.

Secondly, it should be noted that the constitution of the Earth with the Moon is described differently than it actually exists in the Automaton, as was revealed by an internal inspection of it. For in the Automaton itself, the ring AB has 137 teeth, not on the interior circumference as described, but on the exterior; nor is the Earth's orbit annual but rather smaller, and it is not fixed between the orbits of Mars and Earth, but between those of the Earth and Venus. Around this ring rotates the orbit of the Earth CD, to which three small axles are attached perpendicularly, held by a retainer, which we chose not to depict so that the axles might appear more clearly. The first axle has two cogwheels attached to either end See Table 3, Fig. 6., E and F, of which the lower one has twelve teeth engaged with the teeth of the ring AB, and the upper one has thirteen. The teeth of the upper one are engaged with the twelve teeth of the wheel H, and the teeth of this one with the twelve teeth of the wheel G, which has a cavity in its axle opening toward the front part of the planetary board, in which cavity is fixed a small stylus connected to the body of the Earth and the small lunar ring. This is how the matter stands in the Automaton itself; from this description it is manifest that, when the terrestrial ring is revolved according to the order of the signs, the first axle, equipped with the two wheels E and F, rotates in the same directions, but the wheel H rotates in the opposite direction, and this one in turn causes the wheel G, together with the lunar ring, to rotate in the same directions as the order of the signs. The Author does not seem to have described this constitution of the Earth and Moon, even though this is how it is in the Automaton, because he preferred the one he did describe, which, in all likelihood, only occurred to him after the machine was completed; and also because there is more space.