Analysis of information sources in references of the Wikipedia article "Saint Isaac's Cathedral" in English language version.
Twelve great gilt angels, taking the part of the caryatides, support consoles on which stand the bases of the pilasters which form the interior row of the dome and separate the windows. They are twenty-one feet high, and were made by the galvanoplastic process in four pieces, whose welding together is invisible. They could in this manner be made so light that, in spite of their dimensions, they would not be too heavy for the cupola. This crown of gilt angels, poised amid a flood of light, and shining with rich reflections, produces an extremely rich effect.
