William Harkness

“ As just stated, I failed to discern any with the double image prism; but that is not a very delicate test, although, owing to the small size of the nucleus, it is almost the only one practicable. Under the magnifying power used the coma filled the field of view with bright light, and yet exhibited not a trace of polarization when tried by that most delicate of all tests, the Savart polariscope: thus apparently confirming the testimony of the spectroscope that the coma is self-luminous. ”

“ Recourse was then had to a three-inch telescope armed with an eye-piece magnifying 34·5 diameters, and the image of the comet given by it was examined, first with the double image prism, and subsequently with a Savart polariscope, but neither of these instruments showed any polarization. Mr. Huggins thinks he has detected the Fraunhofer lines in the continuous spectrum of the nucleus, and if this really is the case its light must be at least partly derived from the sun. ”