42 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



received only 74 times. At Locle the signal was missed 128 

 times, and at Chaux-de-fonds it was missed 92 times in the 

 course of the year. These imperfections are attributed di- 

 rectly to the want of proper telegraphic facilities ; and the 

 experience of fifteen years has shown the force of the recom- 

 mendation of the director of the observatory, who urges that 

 lie should have under his control a special telegraphic wire 

 for the use of the observatory, at least during certain hours 

 of the day. The testing of chronometers is undertaken by 

 the observatory at Neuchatel on a very large scale for the 

 benefit of the chronometer-makers of Switzerland. The to- 

 tal number tested being 239 during the year. The mean 

 average daily variation of the marine chronometers has been 

 0.02 of a second of time. First-class pocket chronometers, 

 0.44 of a second; second-class pocket chronometers 0.55 of 

 a second ; and, in general, only five per cent, of the chronom- 

 eters show a mean variation exceeding half a second. It is 

 reported that the anchor escapement steadily acquires favor 

 both among manufacturers and the public. The chronome- 

 ters having a Breguet flat spiral hair-spring show a superi- 

 ority over all the others, except those having Phillips's flat 

 spiral, or double curvature. Although the number of marine 

 chronometers is very small, yet they have shown a remark- 

 able excellence, especially the one presented for testing by 

 Henry Grandjean, of Locle, which stands at the head of the 

 list for the perfection of its temperature compensation. 

 Bulletin Soc. des Sciences Natuvelles^ Neuchatel^ 1875, X. 



EGYPTIAN CHBONOLOGY. 



South communicates to the Academy of Sciences at Mu- 

 nich an exhaustive memoir on the Sothis or Sirius period of 

 the old Egyptians. He intends his memoir on Egyptian chro- 

 nology as complementary to that on Egyptian history which 

 he published some five years ago. From his complete re- 

 view of the subject we note that he concludes that the fifty- 

 second year of Sesostris coincides with the Phoenix epoch, or 

 1525 years B.C.; and the eighth year of Barneses HI. coin- 

 cides with the Sothis epoch, or 1325 B.C. And he therefore 

 finds no reason for changing materially the traditional exo- 

 dus of the Hebrews, usually put at 1490 B.C., in which he 

 diflers somewhat from Lepsius, who places the exodus under 



