D. Todd — Amherst Eclipse Expedition. 557 



So the instrument was dismounted at the Museum three days 

 before the eclipse ; and although Smala was nearer the frontier 

 where battles were imminent, it seemed best to take it there 

 and so increase the chances of getting the corona, especially as 

 Professor Sleusarefsky had been able to replace the Dallmeyer 

 lens at the Museum with a Voigtlander objective of nearly 

 equal power. 



At Smala I was farther fortunate in the enthusiastic interest 

 and assistance of Prince Troubetskoy ; and with the help of a 

 local carpenter and photographer we got the instrument into 

 perfect adjustment in ample time the day before the eclipse. 

 It was rigidly mounted on the south balcony of Count Bobrin- 

 sky's residence, and the necessary practice drill was perfected. 

 The plates on which we got the best pictures were made in 

 Moscow ; and greatly to our regret the thin clouds drifting 

 over the sun during the entire time of total eclipse were suffi- 

 cient to obscure the outer corona completely, although two of 

 the plates give the inner corona very satisfactorily. 



Clear night-time skies after the eclipse also enabled me to 

 carry out successfully a plan for fixing on the photographic 

 plate, alongside the corona, a sharply defined line to mark the 

 zero of reference in measuring up the prominences and filaments. 

 This was done in the following manner: leaving the camera 

 in position till night came on, the coronal plate was returned to 

 the camera, and exposed to the trail of oc Ophiuchi, for two 

 minutes on the preceding side of the sun and three minutes fol- 

 lowing. Developing the star-trail and corona together, the 

 trail provides the direction of the " parallel " as an exact zero 

 of position. In the next total eclipse, on the 3d of February, 

 1916, Sirius will be similarly located, and most helpful in exact 

 adjustment of eclipse instruments, as well as star-trails after- 

 ward. 



Every courtesy of the officials of the Russian Government 

 and the Imperial Academy of Science was accorded the Expe- 

 dition ; also of Dr. Backlund, director of the Observatory at 

 Pulkowa, who kindly permits our instruments to be stored at 

 Pulkowa till after hostilities. 



Returning homeward by the roundabout route through Fin- 

 land and Sweden, I met at Stockholm Dr. E. Nordenmark, 

 who had got the eclipse with a cinematograph at Solleftea, 

 Sweden, in a perfectly clear sky. This film contains many 

 hundred impressions of the corona, at a speed of six to the 

 second ; and shows also a fine coronal ring on all exposures 

 just before and after totality. This first complete success of 

 the cinematograph is of great interest as indicating the availa- 

 bility of automatic photography for the portrayal of the swift 

 development of a total eclipse. 



Amherst College Observatory, Nov. 6, 1914. 



