Hijibry of Aftronomy for the Year i8o2. 215 



C. Leveque has publidied, in the fourth volume of the 

 Memoirs of the Inftitute, a learned paper on the longitude, 

 and particular! V on Maignon's charts tor reducing the moon's 

 diftances obferved at fea. 



C. Richer has made a new trigonometric compafs, or com- 

 pafs for reducing the moon's diftances from the ftars. It has 

 ingenious inventions for dividing into unequal parts the rules 

 containing the diftance, the fum, and the diflFerence of the 

 heights, \\\ my (liort Treatifc of Navigation I have given 

 a delcription of the inftrument which gained the prize in 

 1 791 ; and in the Conno'ijfance des Temps for the year 4, the 

 demonftration of the formula of M. de la Grange, which 

 ferves as a foundation for this inftrument; which, howe^'er, 

 has been much improved : the only inconvenience is, that 

 it will coft 60 D francs. 



Mr. Troughton has finifhed the model of Menoza's circle, 

 which gives the double of the multiple of Borda's circle, even 

 retaining the fmalleft fixed mirror. 



A curious detail refpefting the calendar of the Indians has 

 been publifhed in the letters of the abbe Sevin. 



C. Girard read in the Inftitute a long memoir on the Egyp- 

 tian milometer, the value of which he determined in the 

 ifland Elephantine, on the very fpot, 19 feet ^-6 lines; 

 which fhows that the antient mcafuremenl of the earth by 

 Eratofthones was very corre6t. 



The abbe Tefta has publiftied at Rome a differtation on 

 the zodiac found at Dendara (in Greek, Tenthyris) in Egvpt. 

 He undertakes to prove that it is not older tnan 300 years 

 before the vulgar aera. The Hiftory of Herodotus, tranflated 

 by Larcher, edition of 1803, contains a fally againft the un- 

 believers, who carry back the period of one of the zodiacs 

 of Tentyra, at prefent Dendera, and of EIne, or Henne, to 

 6000 years ; and the author's only reafon is, that it would 

 be 217 years before the creation. 



He adds a notice by Vifconti, who fays that the firft fign 

 of the great zodiac is Leo; that Libra, the fynibol of the 

 equinox, is in its place ; and that the refemblance of the 

 greater parts of the figns to the Grecian proves that this 

 zodiac was conftruitcd at a time not fo remote as the earliefl; 

 periods of the Greek aftronomy : he is almoft convinced that 

 this work belongs to the firft century of the vulgar asra. 



The exterior cornice exhibits a large Greek infcription, 

 which may decide the queftion; but another Greek inlcrip- 

 tion contains Roman names, and announces a Casfar, who 

 could be only Auguftus or Tiberius. In a word, M. Vifconti 

 fays that the architecture of the temple of Tentyra, though ia 

 I' 4 the 



