June 4, 1891] 



NATURE 



109 



vernal equinox. Or if we take that part of the ecliptic 

 which is nearest to the north pole and therefore the 

 declination of which is greatest, viz. 23.^° N., we have 

 there the position of the sun at the summer solstice, and 

 23^° S. will give us the position of the sun at the winter 

 solstice. So by means of such a globe as this it is quite 

 possible to determine the position of the equator among 

 the stars, and note those four important points in the 

 solar year, the two equinoxes and the two solstices. I 

 have taken a period of 8ooo years, but I might just as 

 easily have taken a greater or a smaller number. By means 

 of this arrangement, therefore, we can determine within 

 a very small degree of error without any laborious calcula- 

 tions, the distance of any body north or south of the 

 equator, i.e. its declination. 



The positions thus found, say, for intervals of 1000 

 years, may be plotted on a curve, so that we can, with a 

 considerable amount of accuracy, obtain the star's place 

 for any year. Thus the globe may be made to tell us 

 that in the year 1000 A.D. the declination of Fomalhaut 

 was 35° S., in 1000 B.C. it was 42°, in 2000 it was about 

 44°, in 4000 it was a little over 42° again, but in 6000 B.C. 

 it had got up to about 33"^, and in 8000 B.C. to about 22". 



The curve of Capella falls from 41° N. at o A.D., to 10° 

 at 6000 B.C., so we have in these 6000 years in the case of 

 this star run through a large part of that variation to 

 which I drew your attention. 



Here is the curve of Sirius. This star, in o A.D., had 

 a declination of 24" S. ; but 5000 years B.C. it had a 

 declination of something like 3ii°. In Sirius we have 

 the curve plotted from the computations of Mr. Hind, 

 who has kindly placed them at my disposal. From 

 other computations supplied by him, I have ascertained 

 9 that the globe is a very good guide indeed within some- 

 ■ thing like 1° of declination, always assuming that the star 

 f has no great proper motion. Considering the difficulty 

 of the determination of amplitudes in the case of build- 

 ings, it is clear that the globe may be utilized with 

 advantage, at all events in the first instance. 



Now that we are familiar with the effect of the preces- 

 sion of the equinoxes in changing the amplitudes of the 

 rising and setting places of stars, we can return to the 

 consideration of the temples. So far, we have considered 

 those built in relation to the sun, in the case of which 

 body there is, of course, no precessional movement, so 

 that a temple once oriented to the sun would remain so 

 for a long time. After some thousands of years, however, 

 the change in the obliquity of the ecliptic would produce 

 a small change in the amplitude of a solstice. 



Suppose we take, as before, that region of the earth's 

 surface in the Nile valley with a latitude of about 26° N. 

 The temples there built to observe the sun will have 

 an east and west aspect true if they have anything to 

 do with the sun at the equinoxes, and will have an 

 amplitude of about 26° N. or S. if they have anything to 

 do with the sun at the solstices. 



The archaeologists who have endeavoured to investigate 

 the orientations of these buildings have found that they 

 practically face in all directions ; the statement is that 

 their arrangement is principally characterized by the 

 want of it ; they have been put down higgledy-piggledy ; 

 there has been a symmetrophobia, mitigated by a general 

 desire that the temple should face the Nile. This view 

 may be the true one, if stars were not observed as well 

 as the sun ; for at Thebes, if any temple have an ampli- 

 tude more than 26^ N. or S. of E. or W., it cannot by 

 any possibility have been used, as we have seen the 

 temples at Karnak might have been used, for observa- 

 tions of the sun ; for since the maximum declination of 

 the sun is almost 24^° (it is at present only 23^"^), repre- 

 sented by an amplitude of 27°, no temple oriented in a 

 direction more northerly or more southerly could get the 

 light of the sun along its axis. 



NO. I 127, VOL. 44] 



Let us see, then, if the builders of them had any idea 

 in their minds connected with astronomy. If they had, 

 we may conclude that there was some purpose of utility 

 to be served, as the solar temples were used undoubtedly, 

 among other things, for determining the exact length of 

 the solar year. When we come to examine these non- 

 solar temples, the first question is. Do they resemble in 

 construction the solar ones 1 Are the horizontal telescope 

 conditions retained ? The evidence on this point is over- 

 whelming. Take the temple of Denderah. It points 

 very far away from the sun ; the sun's light could never 

 have enfiladed it. In many others pointing well to the 

 north or south, the axis extends from the exterior pylon 

 to the Sanctuary or Naos which is found always at the 

 closed end of the temple. We have the same number of 

 pylons, gradually getting narrower and narrower as we 

 get to the Naos, and in some there is a gradual rise 

 from the first exterior pylon to the part which represents 

 the section of the Naos, so that a beam of horizontal 

 light coming through the central door might enter it 

 over the heads of the people flocking into the temple, 

 and pass uninterruptedly into the Sanctuary. 



In these, as at Karnak, you see we have this collimating 

 axis. We have the other end of the temple blocked ; 

 we have these various diaphragms or pylons, so that, 

 practically, there is absolutely no question of principle of 

 construction involved in this temple that was not involved 

 in the great solar temple at Karnak itself. 



We made out that in the case of the temples devoted 

 to sun-worship, and to the determination of the length of 

 the year, there was very good reason why all these at- 

 tempts should be made to cut off the light, by all these dia- 

 phragms and stone ceilings, because, among other things, 

 one wanted to find the precise point occupied by the 

 sunbeam on the two or three days near the winter and 

 summer solstices in order to determine the exact moment 

 of the solstice. 



But if a temple is not intended to observe the sun, 

 why these diaphragms? Why keep the astronomer, or 

 the priest, so much in the dark ? There is a very 

 good reason indeed ; because the truer the orientation 

 of the temple to the star, and the greater the darkness 

 he was kept in, the sooner would he catch the rising 

 star. In the first place, the diaphragms would indicate 

 the true line that he had to watch ; he would not have to 

 search for the star which he expected ; and obviously the 

 more he was kept in the dark the sooner could he see the 

 star. 



The next point that I have to make is that in the case 

 of some of these temples which are not directed to the 

 sun we get exactly the same amplitudes in different 

 localities. To show this clearly it will be convenient to 

 bring together the chief temples near Karnak and those 

 having the same amplitudes elsewhere. 



We can do this by laying down along a circle the different 

 amplitudes to which these various temples point. To 

 begin with, I will draw your attention to those temples 

 which we have already discussed with an amplitude of 27° 

 or 26°, at Abydos, Thebes, and Karnak. Next we have 

 non-solar amplitudes at Karnak and Thebes, associated 

 with temples having the same amplitude at Denderah, 

 Abydos, and other places. We have the majority of 

 the non-solar temples removed just as far as they 

 can be in amplitude from the solar ones, for the 

 reason that they are as nearly as possible at right angles 

 to them. We have temples with the same ampHtudes 

 high north and high south, in different places— temples, 

 therefore, which could not have been built with reference 

 to the sun ; just as we have at different places temples 

 with the same amplitudes which cotild have been used 

 for solar purposes. 



In connection with the possible astronomical uses of 

 these temples, I find that when one of these temples has 

 been built, the horizon has always been very carefully left 



