16 



May 16th, 1885. 



J. W. ADDYMAN, on "SUN-SPOTS AND COEON.E." 



J. W. Addyman, B.A. Lond., in the course of his address, gave 

 a brief account of a mode of observing the sun with ordinary telescopes by 

 projecting the image on a paper screen. The general appearance of the 

 surface of the sun was stated to be that of a brilliaat white disc, covered 

 with faculse, which were patches of greater luminous intensity, and gave 

 the surface a flocculent appearance under low powers. Dark spots also 

 appeared on the surface, mainly in two belts lying between 10 deg. and 

 30 deg. north and south respectively of the sun's equator. The appe;irance 

 of these spots, and their histoiy, their periodicity, and their connection 

 with magnetic storms and variations, were described, and the theories of 

 Faye and Secchi alluded to. This part of the subject was ilhisti'ated on 

 the screen by a reproduction of Professor Langley's drawing of a typical 

 sun-spot. The light-giving surface of the sun — that is, the photosphere — 

 the red layer, called the chromosphere, in which the red prominences or 

 flames are observed, and the corona, or halo of pearly light observed 

 during total eclipses, were successively described. The theories as to the 

 corona, the proofs of its solar origin, and of its constituents as ascertained 

 by the spectroscope, were also discussed, and illustrated by lantern 

 pictures of the corona as observed in various eclipses, and of the red 

 prominences. 



The exhibits included an abnormal gi-owth of the common mushroom, 

 consisting of a group of nine of about equal size from the same base, 

 which was found growing on a heap of sawdust. This was brought 

 by "W. Barwell Turner, F.C.S., F.R.M.S. W. E. Collinge brought 

 Clausilia rugosa var. duhia, a white form of Helix virgata, aud living 

 examples of the Zebra Mussel [Dreissena polymorpha). W. J. Fletcher 

 showed living specimens of Paludina vivipara, and examples of Helix 

 pomatia (the edible Snail) and of Planorbis contortus. J. W. Dixon 

 and F. Emsley showed microscopic objects, the former contributing 

 deep-sea organisms, and the latter Uromyces fiearice, the fungus of the 

 pilewort. 



May 22nd, 1885. 

 W. B. TURNER, F.C.S., F.R.M.S., on "DESMIDS." 



These are a family of the algse or waterweeds, microscopic, very minute 

 in size. Their form is very curious; and presents the appearance of rosettes, 

 circles with radiating spikes, lunettes, crosses, and other fantastic and 

 beautiful shapes. The outer coat or membrane of these tiny organisms 

 consists of hardened cellulose, and is in many prettily ornamented with 

 spots, dots, raised bead-like markings, or often scattered over with warts or 

 tiny spines. The membrane contains the "cell -contents" (chlorophyll), of 



