156 On Noises accompa7if/ing the Aurora Borealis. 



sied in attaching its body permanently to the surface of the glass. 

 After they have fixed, they become flat and circular, and the 

 more opaque parts of the ova assume a radiated appearance ; so 

 that they now appear, even to the naked eye, hke so many mi- 

 nute grey coloured stars, having the interstices between the rays 

 filled with a colourless transparent matter, which seems to harden 

 into horn. The grey matter swells in the centre, where the 

 rays meet, and rises perpendicularly upwards, surrounded by the 

 transparent horny matter, so as to form the trunk of the future 

 zoophyte. The rays first formed are obviously the fleshy cen- 

 tral substance of the roots, and the portion of that substance 

 which grows perpendicularly upwards, forms the fleshy central 

 part of the stem. As early as I could observe the stem, it was 

 open at the top ; and, when it bifurcated to form two branches, 

 both were open at their extremities, but the fleshy central mat- 

 ter had nowhere developed itself as yet into the form of a poly- 

 pus. Polypi, therefore, are not the first formed parts of this 

 zoophyte, but are organs which appear long after the formation 

 of the root and stem, as the leaves and flowers of a plant. 



From these observations it appears that the so-named ova of 

 many zoophytes, when newly detached from the parent, have the 

 power of buoying themselves up in the water, by the rapid mo- 

 tions of ciliae placed on their surface, till they are carried by the 

 waves, or by their own spontaneous efforts, to a place favour- 

 able for their growth, where they fix their body in the particu- 

 lar position best suited for the future development of. its parts. 

 How far this law is general with zoophytes, must be determined 

 by future observation. 



On the Noises that sometimes accompany the Aurora Borealis. 



JlIaving, many years ago, both in this country and in the Shet- 

 land Islands, heard very distinctly noises proceeding from the po- 

 lar lights, we have always given full credit to the statements of 

 those observers who have published accounts of this fact. It is 

 true, that late observers, particularly our friends and former pupils 



