490 



NA TURE 



Oct. 7, 1875 



began with Aries and the year with Nisan, neither the 

 Zodiac nor the Calendar of the Accadians could be 

 earlier than 2540 B.C. This is also indicated by the fact 

 that even as late as the composition of the " Observa- 

 tions of Bel," time is calculated in the case of echpses, 

 not by the casbu, or " double hour "—a word which is 

 Accadian, and not Semitic— but by the older division into 

 three watches. These consisted of four hours each, 

 beginning at 6 P.M. and ending at 6 A.M,, and they were 

 called respectively the " evening," " middle," and " morn- 

 ing " watches. Something like an accurate measurement 

 of time was attained by the invention of the clepsydra. 



Eclipses of the moon were observed from a very early 

 epoch ; but numerous as are the records of them in the 

 great astronomical work of Sargon's Library, the vague 

 and unscientific way in which they are recorded renders 

 them of little value. The usual formula is : " In the 

 month so and so, on the 14th day, an eclipse takes 'place, 

 beginning on the east and ending on the west : it begins 

 in the middle watch [10 P.M. to 2 A.M.], and ends in 

 the morning watch, the shadow being eastward from the 

 commencement to the cessation of the eclipse." In sub- 

 sequent times, however, the language of the observatory 

 reports becomes more precise and the gradual progress of 

 an eclipse is carefully described. Long before the reign 

 of Sargon of Agan^, the discovery had been made that 

 lunar eclipses recur after a cycle of 223 lunations, and 

 records of them incorporated into the " Observations of 

 Bel " generally begin with the words " According to cal- 

 culation," or (it may be) " Contrary to calculation, the 

 moon was eclipsed." One of the most curious tablets 

 now in the British Museum is one of lunar longitudes, 

 which seems to have formed part of the great Babylonian 

 work on Astronomy, but, since it is written ;in Accadian, 

 must be older than 2000 B.C. As a translation of it has 

 not been made before, it is here given in full : — 



The 1st day (the moon) advances 5 deg. 



The 2nd day ,, ,, 10 deg. 



The 3rd day „ ,, 20 deg. 



The 4th day ,, ,, 40 deg. 



The 5th day ,, „ 80 deg. 



The 6th day ,, „ 96 deg. 



The 7th day „ ,, 112 deg. 



The 8th day ,, „ 128 deg. 



The 9th day ,, ,, 144 deg. 



The loth day ,, ,, 160 deg. 



The nth day ,, „ 176 deg. 



The 1 2th day ,, ,, 192 deg. 



The 13th day ,, ,, 208 deg. 



The 14th day „ ,, 224 deg. 



The 15th day ,, „ ... ... 240 deg. 



The i6th day for 224 deg. of advance it retrogrades* 16 deg. 



The 17th day for 208 deg. ,, ,, 32 deg. 



The i8th day for 192 deg. ,, ,, 48 deg. 



The 19th day for 176 deg. ,, ,, 64 deg. 



The 20th day for 160 deg. ,, „ 80 deg. 



The 2ist day for 144 deg. „ ,, 96 deg. 



The 22nd day for 128 deg. ,, ,, 112 deg. 



The 23rd day for 112 deg. ,, ,, 128 deg. 



The 24th day for 96 deg. ,, ,, 144 deg. 



80 deg. ,, „ 30 deg. 



32 deg. „ ,, 56 deg. 



23 deg. ,, ,, 12 deg. 



15 deg. „ . „ 26 deg. 



S^Vdeg. „ „ 4tdeg. 



The 25th day for 



The 26th day for 



The 27th day for 



The 28th day for 



The 29th day for _ 



The 30th day the moon is the god Ami. 



The fractions at the end of the tablet are hard to 



* Literally, " becomes obscure. "J 



explain, and it is unfortunate that the month is not named 

 during which the observations were made, and that we 

 have no other tablet of a similar kind to compare with it. 

 It will be noticed that here, as everywhere else in Baby- 

 lonian mathematics, the soss or 60 was the unit, and also 

 that the path of the moon was divided into 240 (60 X 4) 

 degrees. This corresponds with an analogous division of 

 the equator into 240°, t] Piscium being 60°, y Piscium 

 (or rather a Pegasi) 80°, and so on. An inner circle 

 was drawn within the equatorial and divided into 120 

 (60 X 2) degrees, a line passing through r\ Piscium being 

 30°, and 10° being marked for every 20° of the equator. 

 The ecliptic, " the yoke of the sky " as it was picturesquely 

 called, was divided into 360°, 30° for each sign.* It is 

 curious that no trace is to be found of the 28 nakshatras 

 or lunar mansions of Hindu and Chinese astronomy 

 which have been so confidently assigned to a Babylonian 

 origin. Should M. Biot, however, be right in holding 

 that there were primarily but 24 of these, the four addi- 

 tional ones being added by the Chinese sage, Chcu-kung 

 (B.C. 1 100), it is possible that they might be connected 

 with'the 24 zodiacal 'stars which, according to Diodorus, 

 were called "judges" by the Babylonians, 12 being north 

 and 12 south. 



The problem of calculating solar eclipses by tracing 

 the shadow as projected on a sphere had also presented 

 itself at an early period. Like echpses of the moon, 

 eclipses of the sun are spoken of as occurring either 

 " according to calculation " or " contrary to calculation." 

 In a report sent in to one of the later kings of Assyria 

 by the State Astronomer, Abil-Istar states that a watch 

 had been kept on the ,28th, 29th, and 30th of Sivan, or 

 May, for an eclipse of the sun, which did not, however, 

 take place after all. The shadow, it is clear, must have 

 fallen outside the field of observation. Besides the more 

 ordinary kind of solar eclipses, mention is made of 

 annular eclipses, which, strangely, enough, are never 

 alluded to by classical writers. It is interesting to find 

 that observations were made as early as the time of 

 Sargon of Agand on the varying colour of the sun, espe- 

 cially at the beginning of the year on the ist of Nisan. 

 Thus in one place we^are told that the sun on that day 

 was " bright yellow," in another place that it was " dis- 

 coloured " (or rather " spotted "). 



Of the planets, only Mercury, Venus, Mars, Jupiter, 

 and Saturn were known, besides the earth. These, how- 

 ever, excited great attention, and their phenomena were 

 carefully studied. The movements of Venus and Mars 

 especially attracted notice. Among the names given to 

 Mars was that of "the vanishing star," in allusion to its 

 recession from the earth, just' as Jupiter was frequently 

 called " the planet of the ecliptic," from its neighbour- 

 hood to the latter. The title of Mars just alluded to, 

 however, raises the very interesting question whether the 

 Babylonians had observed the phases as well as the 

 movements of Venus and Mars. Now a report, taken 

 from the " Observations of Bel," distinctly states that 

 Venus "rises, and in its orbit duly grows in size," 

 and this, fn combination with the name of Mars 

 as " the vanishing star," shows plainly that the phases 

 of the two planets must have been noticed. Such a 

 fact necessitates the existence of some kind of telescope, 



* The Babylonian symbol for a degree was the star *). 



