SPECTROSCOPIC OBSERVATIONS. 69 



instantaneous transformation of the lines from dark to bright 

 the moment the continuous spectrum broke up. 



I did not wait for any further developments but immediately 

 uncovered the prismatic camera and the large spectrograph, 

 giving each instrument an exposure of several seconds before 

 replacing the caps. A few seconds after second contact I made 

 an instantaneous exposure with the prismatic camera, and then 

 started a long exposure, at the same time opening the slit 

 spectrograph. Then I left the seat and went to the camera of 

 the large spectrograph, closing the slide, reversing, and opening 

 again ; then the R.A. handle was turned four revolutions, to 

 bring the whole instrument again into position for the flash 

 .spectrum, which at the end of totality would occur on the 

 western limb. 



Returning to the seat, I closed the prismatic camera long 

 exposure, and started another. During this exposure I took a 

 hurried look at the corona with a pair of fieldglasses. I saw the 

 planet Venus, and noted the shape of the great S.W. streamer, 

 but had no time to look for the prominences or other details : 

 20 seconds only, according to the time-caller, remained before 

 the sun would reappear. It was therefore necessary to prepare 

 for the second " flash." I exposed the prismatic camera once 

 more the last in totality and then, at the moment when I 

 was conscious of returning light, again made a simultaneous 

 exposure with the prismatic camera and large spectrograph. 



After that two snap-shots with the prismatic camera out of 

 totality, following as rapidly as possible, completed the pro- 

 gramme. 



The whole performance seemed to have gone off without any 

 hitch ; but too late I discovered the slit spectroscope still exposed, 

 with the crescent sun right across the slit ! I had forgotten to 

 close the shutter in the hurry of the last moments of totality. 



It will naturally be inferred from this account that I 

 attempted too much and had too many instruments for one 

 person to attend to. It would have been far better, no doubt, 

 to have had one assistant for each instrument, and one besides 

 to record the times of exposures. Unfortunately the assistants 

 were not forthcoming. I am confident, however, that with a 

 day or two devoted to drilling there would have been no difficulty 

 whatever in going through the operations I have described 

 without any mistake. As it was, owing to the unavoidable 

 delay in getting into camp, the work of erection and adjust- 

 ment occupied the whole time even up to the hour of the eclipse, 

 and what little drilling I obtained had to be done in a few spare 

 moments. What I most regret is, that I was unable to obtain 

 a really satisfactory view of the eclipse itself. 



The number of photographs secured altogether was thirteen : 

 one with the slit spectrograph, two with the slitless spectrograph, 



