Solar Spectroscope Observations

Abstract

IN NATURE of the 17th inst. there appear letters from Col. Tennant and Mr. Capron, who seem to doubt that the solar prominences can be seen in England with the facility described by Capt. Herschel in India. I might almost apply Capt. Herschel's words to my own experience last month. With a seven-prism direct-vision spectroscope of Browning (open slit) attached to a 21/4; inch glass mounted on a drawing-room stand, not only the bright lines, but the forms of the prominences, could be plainly seen and were sketched. Of course there were many cloudy days which prevented observations, and there would be many more such in England than in India; but it does not require exceptionally fine weather, only a great deal of practice. Experience only will tell the exact distance at which the slit must be from the sun's limit, and the slightest movement will either put the prominence out of the field or swamp it with a flood of light.