352 



NATURE 



[Feb. 22, 1877 



Aries, or more probably to the time of Hipparchus, when 

 the equinox was exactly at the star /3 Arietis. It occurs 

 to us that the worship of the Bull and Golden Calf was 

 in vcgue during the time that the equinox happened in 

 the constellation of Taurus, that the Ram and Lamb 

 were held in estimation at a later date when the equinox 

 happened in the constellation of Aries. 



The most prominent group of stars in the heavens — the 

 Pleiades — has always been an object of attention, and 

 we are glad to find an interesting chapter on this subject 

 based on the careful work of Mr. HaUburton. The 

 Pleiades, we learn, were observed for the purpose of 

 dividing the year into two parts — one " the Pleiades 

 above," and the other " the Pleiades below." During one 

 half-year, while they were east of the sun, they would be 

 visible at sunset and the reverse during the other half. 

 The culmination of the Pleiades at midnight appears to 

 have been with many nations the starting-point of the 

 year, and here again the precession of the equinoxes 

 has an interesting effect, since the tropical year is 

 shorter than the sidereal. Thus the dates of the latter 

 keep advancing on those of the former, and so long 

 as dates were regulated by the stars all the countries 

 would agree in the time of their festivals ; but, as the 

 author puts it, " as soon as a solar calendar was arranged, 

 and it was found that at that time this position coincided 

 with a certain day, say the Pleiades culminating at mid- 

 night on November 17, then some would keep on the 

 date November 17 as the important day, even when the 

 Pleiades no longer culminated at midnight then, and 

 others would keep reckoning by the stars, and so have a 

 different date.' 



The instance given of the 17th November seems to be 

 somewhat strange, for, on referring to our star maps, it 

 appears that the Pleiades culminate now at midnight on 

 or about the 14th November, and years ago the midnight 

 culmination took place of course earlier in the year. It 

 is, however, possible that judgment of the date of mid- 

 night culmination was in error. 



Mr. Blake then goes on to point out that a new year's 

 festival determined by the Pleiades is the most universal 

 of customs. The Australians hold their new year's corro- 

 borree in November at the midnight culmination, and in 

 India the year was determined by the Pleiades, and on the 

 17th day of November is celebrated the Hindoo Durga, 

 the festival of the dead, and new year's commemoration. 

 So also the Egyptians regulated their solar calendar that 

 the day might be unchanged, and the commemoration of 

 the dead took place on the 17 th of their month Athyr, 

 the same date at which the Mosaic account of the deluge 

 makes the same commence. This, we agree with the 

 author, is no chance coincidence. 



We cannot think, however, that the explanation of the 

 origin of November 17 is clear, for although some 4,000 

 years ago the equinoctial point was close to the Pleiades, 

 there appears no particular reason that the day on which 

 the equinox happened when near that group would be 

 called November 1 7,and if it was so called how comes it that 

 the midnight culmination happens now within three days 

 of the same date, while our calendar has continually been 

 changing with reference to sidereal events ? If we assume 

 that the commemorations of India and other places are 

 kept on the day of midnight culmination of this group, 



without reference to the calendar, then the events would 

 happen now without much error on November 17, and will 

 happen on December 17 some 2,200 years hence, and if we 

 reckon back according to our calendar to a time — to some 

 4,000 years ago — the culmination and festivals would have 

 happened on the autumnal (spring of the southern hemi- 

 sphere) equinox — September 21. We do not see from the 

 text how the Egyptian and Mosaic dates of November 17, 

 although perhaps connected together, can have any con- 

 nection with the festivals of other nations kept on that 

 date in modern times. The calendar might have been 

 arranged to suit the sidereal year up to a comparatively 

 late date, but our calendar has been fitted to the tropical 

 year much too long to allow, at its commencement, the 

 midnight culmination of the Pleiades to have happened 

 anywhere near November 17. 



In other words, the festivals depending on the mid- 

 night culmination of the Pleiades will necessarily be kept 

 on or about the same day, and that day happens to be 

 February 14, or, say November 17; now unless the calendar 

 be a sidereal one, which it is not, this festival must have, 

 in bygone years, happened earlier than November 17. It 

 would seem, therefore, that some other event than the 

 culmination of the Pleiades happened, by which the 

 Mosaic and Egyptian date of November 17 was fixed. 



The further account of the Pleiades and the relation to 

 the passage in the Pyramid of Gizeh, as investigated by 

 Piazzi Smyth, is extremely interesting. 



In the chapter on astronomical systems there is much 

 worth reading, and the diagrams show the gradual ad- 

 vance of observation and order over imagination, and it 

 seems curious to us at the present time that the ancients 

 should have gone so far out of their way to describe the 

 earth as a flat surface floating, with roots, on pillars, on 

 the backs of elephants standing on a tortoise, as a portion 

 of a cylinder, as cubical, or as having various other forms. 

 The geography and cosmography are no less interesting, 

 and a large number of diagrams of maps are given, many 

 of which appear to have been made to suit the super- 

 stitious ideas of the fathers of the various churches rather 

 than the results of observation. 



The chapters on Eclipses and Comets, with the anecdotes 

 of the consternation and awe produced by their appear- 

 ance, give us a very correct idea of the all-supreme super- 

 stition of the middle and earlier ages ; but even now 

 among civilised nations there appears to be a large 

 amount of superstition to be eradicated. 



OUR BOOK SHELF 



Acoustics, Light, and Heat. By William Lees, M.A,, 

 &c. Glasgow: Collins, S^ns, andCo., 1877. (Collins's 

 Advanced Science Series.) 



This is a good specimen of a series of text-books, among 

 which Dr. Guthrie's capital compendium of Magnetism 

 and Electricity, and several other valuable works have 

 appeared. It is stated, in a brief preface, to be founded 

 on notes of the late Dr. W. S. Davis of Derby, who 

 was to have undertaken its preparation, and to whom the 

 first chapter, as well as the Appendix on the Doctrine of 

 Energy, are due. 



Text-books are far from easy to write in a satisfactory 

 manner ; by their very definition and nature they coft- 

 tain no novelty, except such as can be secured by clear 

 treatment and lucid exposition of subjects already familiar. 



