The Altar measured thirty-two amot (about 50 feet) by thirty-two amot at its base. It was constructed by bringing a wooden base of that size, one amah high, and filling it with the mixture of lime, molten lead, and tar. After the mixture hardened and the wooden frame was removed, the remaining structure formed "the base" of the Altar.
The second form was thirty by thirty amot, and it was five amot (about 8 feet) high. It was filled with the same mixture.
The third tier was twenty-eight by twenty-eight amot, and had the height of three amot. On it corners there were protrusions, called “horns,” and the outside of it formed a shelf, known as “the ledge,” which could be used for walking. A ramp led up the Altar from its south side. It was as long as Altar itself, and its width was half that.
Both the stones of the Altar and of the ramp were quarried from the valley of Bait Kerem. They would dig beneath virgin soil and bring from there whole stones that were never touched by iron. Since iron renders the stones, and consequently the whole Altar, unfit by simply touching them, they went to great length to find stones that were unlikely to have been touched by iron. The Altar was protected by a layer coat of lime, and it was only wiped by web cloth.
Art: Gottlieb Daniel Paul Weber - Boulder Crossing, Pennsylvania