THE CORONAVISER 261 



over a period of more than 2 hours. All these show this feature, and 

 its position on each plate is plotted against the time of exposure on 

 Fig. 9. The slope of the line is the correct rate for the turning of the 

 celestial field in the neighborhood of the sun at that time. It was not 

 brighter on the plates that were taken with the red filter than on those 

 taken with white light, and it is concluded, therefore, that it was 

 white in color. 



There was no prominence at its position on the limb of the sun, but 

 the next day the observatory at Huancayo reported that an eruptive 

 prominence blew off from the limb at this position (28° N. Lat.). It 

 seems quite probable that the unusually bright jet in the corona was 

 lying over and probably associated with this active region. 



A number of other plates have shown details which appear to have 

 their origin in the corona, but generally they have been partly obscured 

 by other patterns of instrumental or other origin. 



The major objectives of this phase of the work which were the de- 

 velopment of an adequate instrument and the proving in of the method 

 have been achieved. The next phase of the investigation should be 

 carried out under the most favorable conditions possible and this 

 means a location on a mountain top with a telescope preferably point- 

 ing directly at the sun. 



I wish to acknowledge the helpful cooperation of Dr. Cook and his 

 associates at the Cook Observatory and of many of my colleagues in 

 the Bell Telephone Laboratories. In particular, Dr. J. B. Johnson 

 has greatly contributed to the investigation by his counsel and aid. 



