GREEK TEMPLES AND THE DATES OP THEIR FOUNDATION. 
45 
the elements of an orientation, the conditions require that the sun must have been 
depressed to the extent of at least 11°. This view of the matter agrees very well 
with such actual observation as I have l^een able to make. In 1892 I saw Ptigel 
setting after sunset at 2° 40' altitude, the sun being 9° 48' below the horizon. In 
March last I saw Mars easily at his rising before sunrise, altitude 13° o', the sun 
being 8° 45' depressed. The star magnitude of Mars at that time was about 1‘3 
Tn 1892 I liad seen Antai’es in the morning, at an altitude of about 1G°, when the 
sun was not more than 7° 40' below the horizon. On an evening of the same year, 
I saw y Andromedm, second magnitude, at an altitude of 9°, when the sun had sunk 
to 12°. The conclusion I have come to is that (l) a first magnitude star in fail- 
average weather in Greece or Italy could be seen, when rising heliacally, at an altitude 
of 3°, the sun being 10° below the horizon ; (2) that a second magnitude star should 
require an altitude of 3° 30' with the sun 11° depressed ; but that for a third magni¬ 
tude star the sun’s depression should not be less than 13°, and consequently I feel 
that in the elements of orientations in my former paper, I had over-estimated the 
heliacal visibility of the Pleiades in treating them as equivalent to a first magnitude 
star. I have, since then, given a good deal of attention to this constellation 
It is true that I have recorded one instance when it was seen with the sun 
depressed 10° 50', but the considerable altitude of the Pleiades, 10°, was then in their 
favour, and I have not had the opportunity of observing them heliacally at a lower 
altitude. But, for the following reasons, I cannot assign to this constellation for the 
purpose of this inquiry, a greater heliacal value than that of a second magnitude star. 
When the twilight is at all luminous, or when in the neighbourhood of the moon, 
7} Tauri seems to be shorn of the glory which surrounds it in a clear sky, when the 
constellation catches the eye as readily as a first magnitude star; and again, if viewed 
with strongly magnifying spectacles, the dispersed light seems very much inferior to 
that given out by Aldebaran. I am, therefore, fully persuaded that a second magni¬ 
tude vahie for orientation purposes is the right value. I have, therefore, recalculated 
the elements of orientation of those temples in the first list, into which the rising of 
the Pleiades has entered, with the followinof results, viz.:— 
Atliens.—The archaic Temple o£ Minerva.B.c. 2020 instead of 1830.* 
The Hecatompedon.,, 1495 ,, 1150. 
The earlier Temple of Bacchus.,, 1180 ,, 1030. 
Epidaurus.—The Asclepieium.,, 1370 ,, 1275.t 
And in the case of a second magnitude star Arietis) 
to be observed heliacally at an altitude of 3° 30' 
instead of 3° :— 
Tegea.—The older temple.. 1660 „ 1580. 
The later „ „ 1140 „ 1080. 
* In the first paper this date is given as 1530. It should have been 1830. 
t As the star’s altitude, owing to the mountain opposite, was considerable, viz., 7°, the sun’s depression 
is taken at 10° 30' instead of 11°. 
