X OBITUARY NOTICES OF MEMBERS DECEASED. 



both day and night whenever the weather permitted observation. 

 Much was expected in the way of results, superior perhaps to any- 

 thing before attained, but these anticipations were not fully realized. 

 The instrument itself was not what had been expected and the 

 mounting proved unstable, so that the results, instead of the 

 superiority which had been looked for, proved inferior to those 

 reached at the European observatories. 



When a large telescope was installed at Washington toward the 

 end of 1875, Professor Newcomb was placed in charge of the 

 instrument, which at his request was turned over to Professor Hall 

 two years later. This closed Professor Newcomb's activities in the 

 way of systematic observation. 



In 1869 he made application to be transferred to the office of the 

 " Nautical Almanac," with the understanding that his time should 

 be devoted to an investigation of the moon's motion, a problem in 

 which he had become greatly interested. Doubtless there is room 

 for honest difference of opinion as to the relative importance of the 

 two branches of astronomical work, but if the lunar problem was to 

 have been taken hold of at this time, there is no question as to whom 

 it should have been entrusted. Men could be found in plenty who 

 were capable of reaching valuable results in the field of observation, 

 but those who were capable of attacking with success the most intri- 

 cate of all astronomical problems, the lunar theory, have always been 

 extremely few. The transfer to the " Nautical Almanac " was not 

 made, but the arrangement which resulted was probably even more 

 satisfactory. A few years before Newcomb began his work on the 

 moon, the lunar tables of Hansen had been published. They were 

 based on a part only of the Greenwich observations from 1750 to 

 1850, and represented with practical accuracy the moon's motions for 

 this period of a full century. But, in the course of a very few years, 

 the actual position was found to deviate very appreciably from those 

 given by the tables, the deviations increasing from year to year. 

 What the state of things previous to 1750 had been was a very 

 interesting question, but one not easy of solution, as very little 

 material accurate enough for such an investigation was known to 

 exist. 



