415 
of Edinburgh, Session 1876-77. 
accompanied by these rapid upper movements, while polar winds 
move with a greater uniformity in the velocity of their various 
layers, and sometimes even those on the surface move more rapidly 
when copiously supplied from a vertical source. There is thus a 
remarkable diference in their mode of inflow. Equatorial winds, 
as they increase in force, are hence accompanied by “ lilting” and 
a fall of the barometer. Polar winds are not attended by “ lifting,” 
and if their supply is copious and partly from a vertical source, 
their increase in force is accompanied by a rise of the barometer. 
The range of the thermometer is equally great, both above and 
below its mean ; but with the barometer the extent of its range 
above the mean is not more than one-half of that which takes 
place when it is below it. When it is below the mean, equatorial winds 
generally prevail, which are accompanied by lifting and extensive 
range. When above the mean, polar winds prevail, which are not 
attended by lifting or such extensive fluctuations. Hence, as a 
general rule, equatorial winds exhibit fictitious or dynamical 
pressure, while polar wincjs possess more nearly, real or statical 
pressure, being less accompanied by rapid upper currents, and by 
the mechanical oscillations due to the passage of air over a resisting 
surface. 
Observations of a general description and illustrations will pro- 
bably be afterwards introduced to exemplify the above conclusions. 
It is to this diference in the mode of inflow that an attempt has 
been made to explain the causes why depressions move in an 
easterly direction. 
5. Laboratory Notes. By Professor Tait. 
(«) On an Effect of Heat on Electro-Static Action. 
By means of a very delicate galvanometer, transient currents 
were detected when one of two plates of the same, or of different, 
metals, separated by a sheet of mica or glass, was suddenly 
heated. 
( b ) On Dr Blair’s Scientific Aphorisms in connection with the 
Ultra-Mundane Particles of Le Sage. 
Accident has recently called my attention to a work entitled 
Essays on Scientific Subjects , by Kobert Blair, Regius Professor of 
VOL. IX. 3 x 
