590 Scientijic Intelligence. 
much more oblique. Various attempts were made to fix these 
wave-surfaces, but without succes e best results were ob- 
tained by covering the surface of the vibrating mercury wit 
by the ridges of the waves. een these are less luminous 
lines produced by the hollows. Bright points are formed at the 
intersections 0 th. As the movement dies aw the lines 
to the longer; though sometimes components of both are 
urf 
ments Bart y ded the two following laws: Ist, the 
breadth of the undulations is inversely as the number of vibra- 
tions ; and tance between two lines produced by the 
gons, the centers of which are the angles of fainter hexagons, 
having the radii of the first set for sides. As the motion lessens, 
apable of similar vibration.” So also clouds are arranged often in 
bands, being then considered a precursor of fine weather. 
ology, the author thinks certain regular and equidistant 
