Spectroscopic observations of the solar prominences, being extracts from a letter addressed to Sir J. F. W. Herschel, Bart., F. R. S., by Captain Herschel, R. E., dated ‘Bangalore, June 12th and 15th, 1869.'" Communicated by Sir J. Herschel

I have too little time to devote to lengthy descriptions, and so I send you asketch of what I saw this morning (fig. 1). I have seen many such views during the last month, but none so distinct in outline as to-day—more by token I have been waiting many days for sunshine since I brought my apparatus to its present state. I can only devote a single morning hour to it (before breakfast), but I make a little advance every day. The dark band across is a slit-image corresponding to C (aperture about 1'). Through the slit, as through a screen, is seen themonochromatic image of the “chromosphere,” a continuous envelope, which may be seen of nearly the same width everywhere. I estimate it at 20" to 30". Through the slit comes also a segment of the true limb, whose light is scattered up and down. It is wanting in C-light, and therefore within the C-image of the slit is seen adark segment of the sun’s limb, an inversion which nothing but "luminology” can enable one to understand. There are two classes of solar cloud represented here; viz. the fleecy and the well defined: in both cases I have taken the liberty of seeing round the corner (so to speak), and giving the whole form as it might be seen by slightly pressing on the tube. With this exception, and a like one due to my having (to avoid confusion) retained a slightly stronger definition inthe central parts than one actually obtains when so much of the limb is seen, there is, I believe, no exaggeration. The whole picture, of course, is to he supposed seen on a background of pretty strong solar spectrum; and the vertical streaky light is to be supposed just short of dazzling—as strong, in fact, as the eye can bear without losing its power of distinguishing relative intensities.