Astronomy 577 



LUNAR PHOTOGRAPHY 



THE Report for 1893 contains the following paragraph on 

 this subject, written by Doctor Langley, explaining the plans 

 of the Institution : 



" I have been interested for a considerable time in the 

 possibility of preparing a chart of the moon by photography 

 which would enable geologists and selenographers to study 

 its surface in their cabinets with all the details before them 

 which astronomers have at command in the use of the most 

 powerful telescopes. Such a plan would have seemed chimer- 

 ical a few years ago, and it is still surrounded with difficulties ; 

 but it is probable that within a few years it may be success- 

 fully carried out. 



" No definite scale has been adopted, but it is desirable that 

 the disk thus presented should approximate in size one two- 

 millionth of the lunar diameter ; but while photographs have 

 been made on this scale, I do not think any of them show 

 detail which may not be given on a smaller one. I have 

 been favored with the cooperation and interest in this work 

 of the director of the Harvard College Observatory, of the 

 Lick Observatory, and others, who, in response to a letter 

 addressed to them on February 10, 1893, have obliged me 

 with many valuable suggestions. This important work is 

 still under advisement." 



In aid of experiments in lunar photography at the Lick 

 Observatory, several small and timely grants of money have 

 been made. 



The present state of the research at Mount Hamilton is 

 that its focal negatives (about five and one quarter inches in 

 diameter) are being enlarged by photography to a scale of ten 

 feet to the diameter by Professor L. Weineck, Director of the 

 Observatory in Prague, and it is expected that a complete 



