1910] Lowell Ohservatory Photographs of tlte Planets. 815 



WEEKLY EVENING MEETING, 



Friday, April 8, 1910. 



His Grace The Duke of Northu3Iberland, K.G. P.O. D.C.L. 

 LL.D. F.E.S., President, in the Chair. 



Professor Percival Lowell, A.B. LL.D., 



Author of "Mars and its Canals," "Mars as the Abode of Life," 

 " The Evolution of Worlds," etc. ; Director of the Observatory 

 at Flagstaff, Arizona ; Honorary Professor of Astronomy at the 

 Massachusetts Institute of .Technology. 



Lowell Observatory Photographs of the Planets. 



The pictures which I have the honour of showing you to-night 

 represent the results of the new planetary photographv originated 

 at Flagstaff in 190o-1005, and now beginning to be successfully 

 copied elsewhere, notably this last summer by M. le Comte de la 

 Baume-Pluvinel and M. Baldet in France, who from the summit of 

 the Pic du Midi de Bigorre succeeded themselves in getting imprints 

 of the canals of Mars. Although the method was originally designed 

 to exhibit the markings of what is practically our nearest neighbour 

 in space, it has since been applied to the other planets with an 

 outcome as surprising as it is satisfactory. Little details which one 

 would not have supposed could sit still long enough for their pictures 

 to be taken stand out unmistakably on the plates ; the faint equa- 

 torial wisps of Jupiter offering a good example of such tractability, 

 though by no means the most remarkable. 



That the canals of Mars should be made to write their own 

 signatures on a photographic plate was the occasion of the invention 

 of the process, which, after long and patient study by my assistant, 

 Mr. Lampland, they were finally induced to do. To his marvellous 

 feat the best tribute was that of Schiaparelli, who, after recognising the 

 canals on the print sent him, wrote me in wonder that photography 

 could be made to do such work, " I would never have beHeved it 

 possible." Since then further improvement has been reached to 

 which almost every member of the staff has contributed. The 

 process is based upon what our visual study of the planets has 

 taught us to be the crux in the matter : the all-importance of 

 definition. For this reason the older celestial photography which 

 furnishes such beautiful pictures of the stars and nebulae was here 

 impotent. This will be realised when one considers that the whole 



Vol. XIX. (No. 104) 3 h 



