The diversity of width which I have indicated as a desirable feature in a meridional gallery, is a marked feature of the actual gallery. "In the casting and ranging of the marbles" (limestone), "in both the side walls, there is one piece of architecture," says Greaves, "in my judgment very graceful, and that is that all the courses or stones, which are but seven (so great are these stones), do set and flag over one another about three inches; the bottom of the uppermost course overlapping the top of the next, and so in order, the rest as they descend." The faces of these stones are exactly vertical, and as the width of the gallery diminishes upwards by about six inches for each successive course, it follows that the width at the top is about 3-1/2 feet less than the width, 6 feet 10-1/5 inches, at the bottom, or agrees in fact with the width of the space between the benches or ramps. Thus the shadow of the vertical edges of the gallery at solar noon just reached to the edges of the ramps, the shadow of the next lower vertical edges falling three inches from the edges higher up the ramps, those of the next vertical edges six inches from these edges, still higher up, and so forth. The true hour of the sun's southing could thus be most accurately determined by seven sets of observers placed in different parts of the gallery, and near mid-summer, when the range of the shadows would be so far shortened, that a smaller number of observers only could follow the shadows' motions; but in some respects, the observations in this part of the year could be more readily and exactly made than in winter, when the shadows' spaces of various width would range along the entire length of the gallery. Similar remarks would apply to observations of the moon, which could also be directly observed. The planets and stars of course could only be observed directly. The grand gallery could be used for the observation of any celestial body southing higher than 26° 18' above the horizon; but not very effectively for objects passing near the zenith. The Pleiades could be well observed. They southed about 63-2/3° above the horizon in the year 2140 B.C. or thereabouts when they were on the equinoctial colure.[46] But if I am right in taking the year 3300 B.C. when Alpha Centauri shone down the smaller ascending passage in southing, the Pleiades were about 58° only above the horizon when southing, and therefore even more favourably observable from the great meridional gallery. In passing I may note that at this time, about 3300 years before our era, the equinoctial point (that is, the point where the sun passes north of the equator, and the year begins according to the old manner of reckoning) was midway between the horns of the Bull. So that then, and then alone, a poet might truly speak of spring as the time "Candidus auratis aperit quum cornibus annum Taurus."