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Page:Popular Science Monthly Volume 57.djvu/319

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moon was allowed to radiate upon the bolometer, and the still larger negative deflection of 18 mm. was observed.

The important result was that the corona gave a positive indication of heat as compared with the moon.

This heat, though certain, was, however, too slight to be sub-divided by the dispersion of the prism with the means at hand.

The negatives taken to depict the outer corona show from three to four solar diameters extension for the longest streamers. The equatorial 'wings,' as they recede from the sun, are finally lost in an illuminated sky, without any indication of having actually come to an end.

No attempt to carefully examine the plates taken for intra-mercurial

PSM V57 D319 Dark room and tubes of 135 and 38 foot telescopes.png
Fig. 4. Dark Room and Tubes of 135 foot and 38 foot Telescopes. 5 inch Equatorial in Foreground, Prof. Langley Observing.

planets has yet been possible. It is, however, as has been remarked, doubtful if the very faintest objects will be found, in consideration of the considerable sky illumination during totality. However, Pleione in the Pleiades (a star of the 6.3 magnitude), is plainly seen on one of the plates, and some smaller ones are discernible.

On the whole, the expedition may be considered as promising to be very satisfactory in its results, and that it was so is largely owing not only to the efficient care of Mr. Abbot, but to the many gentlemen who have assisted me with the loan of valuable apparatus, with counsel, with voluntary service and with painstaking observation, to one and all of whom I desire to express my obligations.