December 25, 1903.] 



SCIENCE. 



fSUo 



inch reflectoi's and the twelve- and forty- 

 inch refractors. Pleasures were also made 

 upon the Pleiades group of stars to deter- 

 mine the coustaut of the equalizing wedge 

 photometer. Measurements were also made 

 of comparison stars for faint variables. 



Much progress was also made in the 

 measurement and discussion of photo- 

 graphs of the sun, taken with the spectro- 

 heliograph at the Kenwood Observatory in 

 the years 1892-6, and in other minor hi- 

 vestigations connected with the work in 

 hand. 



SiMox Xewcojib, Washington, D. C. For 

 delennining the dements of the moon's 

 motion and testing the law of (jravily. 

 $3,000. 



Much of the material for this investiga- 

 tion, consisting of computations of places 

 of the moon from Hansen's tables and their 

 comparison with ob.servations, was pre- 

 served in the archives of the Nautical 

 Almanac Office, awaiting an opportunity 

 for their working up. By permission of 

 the Secretary of the Navy, Hon. William 

 II. Jloody, these papers were entrusted to 

 the Carnegie Institution and by the Insti- 

 tution to Professor Newcomb. 



Abstract of h'eport. — The importance of 

 this work grows out of the fact that new 

 tables of the moon are urgently required 

 for the purposes of astronomy and of navi- 

 gation. For a long period the problem of 

 constructing and perfecting such tables has 

 been delayed by an unexplained discord- 

 ance between the observed motion of the 

 moon and the motion which should result 

 from the action of all known bodies upon 

 it. The exact cause of this discordance 

 can not be recorded, because the observa- 

 tions from 1750 to 1850 have never been 

 worked up and compared with the tables. 

 The problem of determining the exact 

 nature of the deviation of the moon from 

 its predicted place is twofold. The obser- 

 vations since 1750 must be worked up. and 



in order to compute the comparison the 

 action of the planets on the moon must be 

 recomputed with a view to determining 

 whether any correction to the past compu- 

 tations is necessary. 



By aid of a grant from the Carnegie 

 Institution an important term of long 

 I>eriod, produced by the action of Venus. 

 has been recomputed. 



Professor Newcomb has taken up the 

 work on the adopted plan of the occulta- 

 tions of stars by the moon, a work that he 

 had begun in connection with the Nautical 

 Ahnanac. This, in connection with the 

 incorporation of other important observa- 

 tions, can probably be completed in two 

 years more. 



E. C. Pickering, Harvard University, 

 Cambridge. IMass. For study of the 

 astronomiced photographs in the collec- 

 tion of Harvard University. $2,500. 

 Abstract of h'eport.— The grant made to 

 Professor Pickering was applied to a great 

 variety of uses. These included sums paid 

 to nineteen different assistaut.s and com- 

 puters, and for other a.ssistance in connec- 

 tion with the Harvard Observatory. 



Each of the numerous investigations is 

 of importance in carrying forward the 

 work going on in the observatory, but they 

 do not appear to be upon sufficiently 

 definite and specific problems, as given in 

 his report, to permit of a distinct state- 

 ment, in most cases, of the progress of the 

 work under the Carnegie Institution grant. 

 Professor Pickering reports that in form- 

 ing a corps of observers to study the photo- 

 graphs, time and money being limited, it 

 was difficult to decide what subjects to. 

 select from this vast amount of material. 

 A number of problems have accordingly 

 been studied which serve to illustrate the 

 various investigations which might be un- 

 dertaken. Abridged results of a portion 

 of these were promptly pul)lished in the 

 TInrv;ir<1 Obscrvatorv Circulars nns. 69 and 



