'52 



NA TURE 



[December i6, 1897 



sunrise effect in the sanctuary, preceded by an heliacal 

 star, can be established, it carries an amount of prob- 

 ability of the truth of the theory which it is very hard 

 to gainsay. 



To us the practical use of such theory is, that it gives 

 the means of determining very approximately the date 

 of the foundation of any temple, namely the time when 

 the sunrise and the heliacal star were so connected. • 



As seen from a given point at its rising or setting, the 

 amplitude of a star (that is, its bearing from true east or 

 west) is subject, as time goes on, to a slow alteration 

 resulting from the displacement of the star, in conse- 

 quence of the celestial movement called the precession 

 of the equinoxes, and this can be calculated with great 

 precision so as to show the date at which it would have 

 been visible as the forerunner of the sun from the 

 sanctuary of a temple. There is architectural evidence 

 in Egypt that attempts had been made to retain the use 

 of such stars, and in two ways : one by a structural 

 alteration in the eastern opening, so as still to allow of 

 its being seen ; and the other as evidenced by finding that 

 a temple, architecturally of later date, but of the same 

 cult, had been built alongside of an older temple which 

 had lost the star which had at one time served as its 

 morning clock. 



Sir Norman Lockyer having been satisfied that the 

 principles of temple buildmg, as above mentioned, had 

 prevailed in Egypt, and being led by a cursory examina- 

 tion of Greek examples to suspect that the same would 

 be found to prevail in that country also, invited me to 

 take up this inquiry with respect to Greek temples, which 

 led to my making a preliminary communication to the 

 Society of Antiquaries in 1891, and a more detailed 

 report to the Royal Society in 1893, of which an abstract 

 appeared in Nature, May 1 1, of that year. The paper 

 itself was published in the Transactions of the Royal 

 Society (vol. 184, pp. 805 et sqq.) to which the supple- 

 ment, already referred to, was published in vol. 190, pp. 

 43 et sqq. The first series contains more than thirty 

 examples, the second nearly as many, and both collections 

 entirely confirm the view of the matter already made 

 highly probable from Egyptian sources. Indeed the 

 second series, chiefly drawn from colonial Greece, is in 

 one respect more satisfactory than the previous one. 



The architectural remains of the greater number of 

 the temples in Greece proper, comprised in the first list, 

 do not accord with the early dates derived by calculation 

 from their orientations ; and it is necessary to assume 

 that in the majority of cases a temple, of which we find 

 the ruins, was built parallel to the lines of an earlier 

 structure which had conformed to the orientation postu- 

 late, and the date arrived at is that of the first foundation 

 on the site. Traces of such earlier foundation can, how- 

 ever, be actually found or inferred in a sufficiently large 

 proportion of the whole to justify the assumption ; but in 

 more than half the cases they have either disappeared or 

 not yet been found. In the colonial examples of the last 

 series, however, quite two-thirds of the orientation dates 

 are consistent with the architectural remains now stand- 

 ing, without need of any hypothesis respecting foundations 

 as yet undiscovered. 



All the temples I have met with in Magna Grecia or 

 Sicily are what may be named solar temples ; namely, 

 those which admit of being lighted through an eastern 

 door by the sun when rising in the line of the axis. 

 Three of them, indeed, lie on the solstitial limits ; of this 

 I did not find any examples in Greece. The nature of 

 the inquiry in a solar temple is of this kind, viz. : given 

 the angle of orientation, and the apparent height of the 

 eastern horizon, we calculate the declination which the 

 sun would have required to illuminate the sanctuary at 

 its rising (allowance being made for the variation of the 

 obliquity of the ecliptic many years ago, an allowance 

 which may require a small correction when an approxi- 



NO. 1468, VOL. 57] 



mate date has been arrived at). From this the sun's 

 right ascension is computed, giving generally two values 

 — one vernal, the other autumnal. The next search is made 

 for a suitable star. It must be remembered that in the 

 case of a rising star the declination cannot differ much 

 from that of the sun, or else it could not be seen through 

 the same narrow opening, and to be serviceable as a 

 warning star, it must precede in right ascension by a 

 suitable interval ; if too short the star could not be seen, 

 if too long its warning would be inconveniently early. 

 Thus the data for the preliminary search are : for declin- 

 ation, that already ascertained for the sun, and for right 

 ascension, one hour less may be taken. 



It would occupy too much space to enter into the 

 details of the calculation which involves the change due 

 to the movement of the star from precession ; but if the 

 result shows that a conspicuous star or constellation, 

 either in the spring or autumn (and within the limits of 

 possible archaeology), occupied approximately the position 

 required by the hypothesis, the discovery will justify 

 a more exact computation. Should it, however, fail for a 

 rising star, there still remains the search for a setting 

 star which would fulfil the proper conditions. The 

 search is conducted on analogous principles, but with 

 difference in detail. 



In more than fifty cases which I have tried by the four 

 lines of investigation indicated above, I have succeeded 

 in finding in each one solution, and one only. In two I 

 have obtained an alternative possible star ; the choice 

 between the two requiring to be settled archccologically. 

 In not one case of which I had full particulars have I 

 failed to find an answer. 



An objection has been made that, as there are so many 

 stars in the heavens, some solution of the problem is 

 inevitable, without there having originally been any 

 intentional correspondence. The answer is not difficult. 

 Firstly, there are very few available stars. They must 

 be of sufficient brightness ; a third magnitude star is 

 the very minimum, and could only be resorted to (unless 

 in a close constellation like the Pleiades or Aquarius) if 

 situated very much by itself, so as not to be mistaken for 

 any other. They must also be near enough to the ecliptic 

 to be seen through the narrow eastern opening. A list 

 of fourteen single stars and two star groups exhausts the 

 whole possible number. Moreover, they must be so placed 

 in the firmament as to satisfy the condition required for 

 warning stars. Again, in the two hundred trials made for 

 the fifty temples, as mentioned above, would there (in the 

 case of the assumed multitude of stars) have been one 

 hundred and fifty misses to the fifty hits which were 

 wanted ; and if there had been no arrangement, and the 

 orientations had been fortuitous, would the most ancient 

 sites have always secured the oldest orientation dates, 

 and those of which the recent foundation is historically 

 known have taken their proper rank ? 



It is true that the sequence might have been accept- 

 able, but not so the exactness of the dates. These must 

 depend upon the correctness of certain assumptions with 

 regard to the elements of the problem, especially as to 

 the altitude of the star and the depression of the sun at 

 the heliacal phase, if it may be so called. 



From a good d*al of attention which I paid to the 

 visibility of stars in twilight I derived the following rules, 

 from which all the calculations have been made, except 

 in a very few cases where local circumstances required 

 some modification. The rules are made for the case 

 of rising stars. When setting in the morning twilight 

 they may be seen nearer to actual sunrise ; but it is 

 probable that the same rule would have been applied, 

 as the same time would have been required for warning, 

 whether a rising or setting star was used. It may be 

 observed that rising stars seem to have been the 

 favourites, in proportion of about three to two. 



In ordinary fair weather in Greece or in South Italy I 



