A very elaborate road, winding round and round the mountain at such an incline as to be easily ascended by the electric carriages, was built.

But this was intended only as a subsidiary means of ascent.

Eight into the bowels of the mountain a vast tunnel fifty feet in height was driven.

At its inner extremity was excavated a chamber whose dimensions are imperfectly recorded in my notes, but which was certainly much larger than the central cavern from which radiate the principal galleries of the Mammoth Cave.

Around this were pierced a dozen shafts, emerging at different heights, but all near the summit, and all so far outside the central plateau as to leave the solid foundation on which the Observatory was to rest, down to the very centre of the planet, wholly undisturbed.