2 | ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Prom this it follows that we have to do with a real inequal- 

 ity theoretically deduced by Xeison. The agreement be- 

 tween the theoretical and Xewcomb's empirical term is a 

 satisfactory one. The two independent results confirm each 

 other and dispose of the doubts expressed as to the reality 

 of this term. 



The numerical lunar theory of Sir G. B. Airy is in a for- 

 ward state, and one section of it is to be printed as an Ap- 

 pendix to the forthcoming volume of Greenwich observa- 

 tions. 



Dr. George W. Hill, of the American Ephemeris, has re- 

 cently printed (privately) an exhaustive treatise on that part 

 of the motion of the lunar perigee wdiich is a function of the 

 mean motions of the sun and moon. From this work we 

 learn that its author is also engaged in other researches in 

 the lunar theory, which are shortly to be published. This 

 work of Dr. Hill has met with a most cordial appreciation 

 abroad from Professors Cayley and Adams. The latter con- 

 firms its principal conclusions from unpublished researches 

 of his own. 



In a recently published pamphlet on astronomy in Rome 

 during the pontificate of Pius IX., Secchi gives an account 

 of his unpublished observations on the lunar surface. 



Professor Alexander, of Princeton, has brought forward a 

 variety of evidence tending to indicate some envelope, like 

 an atmosphere, for the moon. This evidence was principally 

 drawn from observations during eclipses. 



The work of Professor JXewcomb on the Lunar Theory, 

 after Buffering an interruption of some years, was recom- 

 menced in 1876. That part of it which consists of a new 

 reduction and examination of all recorded eclipses and occul- 

 tations of value before 1750 is substantially complete, most 

 of it being in the hands of the printer. The ancient obser- 

 vations which have been considered most reliable indicate 

 a correction of more than half an hour to the times of an- 

 cient eclipses as hitherto calculated from the tables. This 

 correction so changes the computed paths of the moon's 

 shadow during total eclipses that the chronological ques- 

 tions involved in them will no doubt have to be re-examined. 

 The most remarkable result of the research is that the mo- 

 ti"n <>t* the moon during the past 250 years may be very 



