34 [March 20, 



11. Somewhat earlier than these trials of mine were the first 

 efforts of Mr. De la Rue, of which I was not aware. These efforts 

 have from year to year been rewarded with still increasing success, 

 till we have had from his skilful hands maps of the full moon of posi- 

 tive value, and stereographic pictures of admirable beauty. These 

 researches are still in progress, with every prospect of reaching a point 

 from which eye-draughts may be started on a fresh basis for a systema- 

 tic scrutiny of all parts of the moon, and the construction of maps on 

 the scale of -$th of an inch to a mile on the middle part of the moon's 

 face (or as the moon would appear under a power of 1000). 



1 2. Experiments rewarded by considerable success were completed 

 by the Liverpool Photographic Society in 1854 ; and several of their 

 valuable drawings of the moon, magnified to a large scale, were exhi- 

 bited at the Meeting of the British Association in Liverpool, along 

 with one of mine similarly handled. 



II. PROPOSAL OF A METHOD FOR FURTHER PROGRESS. 



13. By the labours, for the most part uncombined, of the last ten 

 years, we have not achieved much beyond laying the foundation for 

 further progress. We have acquired, by means of photography, a 

 general view of the whole moon as to its proportions of light and shade, 

 the degrees of light of different parts of its surface, the direction of the 

 light-streaks, and other phenomena, better than eye- draughts and 

 micrometry could furnish. 



By eye-draughts and micrometry alone many of the " mountains " 

 and " seas" of the moon have been sketched in beautiful landscapes by 

 Nasmyth and Smyth ; and two " ring mountains " have been sur- 

 veyed and drawn in detail by Secchi (Copernicus) and Phillips 

 (Gassendi). 



The next ten years may, doubtless, be justly expected to give an 

 equal rate of progress ; photographic foundation will be made more 

 effective for the whole moon and for different phases of the moon ; 

 and we may add, by individual and sporadic efforts, a few more ring 

 mountains to our meagre catalogue of objects examined. It appears 

 to me, however, that more than this can be attained, and ought to be 

 attempted, on a plan of continuous work, by means of one instrument 

 devoted to a survey of selected parts of the moon, and I proceed to 

 explain my views. 



