Of what this incomparable mountain really is, with all these lines of projections converging towards it and with all these prominent points of relief protruding within its crater, photography has, so far, been able to give us only a very unsatisfactory idea. The reason too is very simple: it is only at Full Moon that Tycho reveals himself in all his splendor. The shadows therefore vanishing, the perspective foreshortenings disappear and the views become little better than a dead blank. This is the more to be regretted as this wonderful region is well worthy of being represented with the greatest possible photographic accuracy. It is a vast agglomeration of holes, craters, ring formations, a complicated intersection of crests--in short, a distracting volcanic network flung over the blistere