Report on the Solar Eclipse Expedition to Viziadrug. 35 



The Coronagraph. 



All the more important instruments available for' the expedition 

 being employed in the spectroscopic work I could only use a small 

 one for taking photographs of the corona, which were essential for 

 me in order to make comparisons with the chromosphere and coronal 

 rings we hoped to get in the prismatic cameras. The instrument 

 employed, of 4f-inch aperture, was entrusted to Staff-Engineer A 

 Kerr, R.N., who was assisted by three volunteers. 



Five photographs were taken. These on development were found 

 to be exceedingly good, the long exposed plate showing a great 

 amount of detail both in the polar rifts and in the streamers. 



There being still a small amount of available surface of the ccelo- 

 stat for other purposes, this was utilised for the 10 x 8 landscape 

 camera which was operated by Mr. Turner. Two exposures were 

 made during totality, with very successful results. The longest 

 exposure shows very well the general form of the corona and the 

 relative lengths of the extensions, the longest streamer being nearly 

 three lunar diameters. 



Discs. 



The discs, six in number, were put into position by Lieutenant Gr. 

 C. Quayle, R.N., and Lieutenant C. E. B. Colbeck, R.K, being 

 ranged along the southern wall of the fort, close to the Eclipse Camp. 

 The great altitude (53) of the sun rendered the operation of setting 

 them up somewhat difficult. Their sizes varied from six to two 

 inches, and they were so placed that they cut off 3, 5, and 7 minutes 

 of arc round the dark moon. 



Each disc occupied the time of three men, so that in all eighteen 

 volunteers were employed. Of each party of three, one volunteer 

 kept the eye end in adj ustment up to the time of totality, another 

 who was blindfolded ten minutes before totality acted as observer, 

 and the third wrote down the remarks of the observer. 



A preliminary examination of the drawings shows that no equa- 

 torial extension was observed. 



The 3%-inch Equatorial Telescope. 



This telescope was used by me to observe the exact time of second 

 and third contacts to give the signals " go " and " over" to the time- 

 keepers. For the first fifty seconds of totality I employed this 

 instrument myself to minutely observe the structure of the rifts and 

 streamers. In my absence it was used by Assistant Engineer H. H. 

 Willmore for the examination of the structure of the corona. 



D 2 



