THE ANNUAL MEETING. 193 



ELECTION OF OFFICERS. 



The committee on nominations reported, and the election resulted in the 

 selection of officers named in one of the first pages in this volume. 



The hour for intermission having arrived, a recess was taken until 2 o'clock. 



Wednesday Afternoon Session. 



After the usual opening with music, Mrs. Pierce read a very pleasant, brief 

 paper entitled " Reciprocity." It was listened to with interested attention, 

 but is not reproduced here because outside the line of horticulture. 



Prof. Harrington, of the State University, followed with an address, illus- 

 trated by crayon drawings on the blackboard, upon 



THE WINDS OP MICHIGAN. 



The object of my remarks will be to point out the general characters of the 

 different sorts of winds of the region of the upper lakes. While many of 

 the special conclusions reached are the results of a study of the winds of Ann 

 Arbor, they will undoubtedly generally apply to the whole of Michigan and 

 to much of the neighboring States. 



A clearer conception of air-currents can be got by remembering that we are 

 at the bottom of an ocean of air, which differs from the ocean of water, 

 among other things, in its greater mobility, in not having the bounds set to it 

 which banks and coasts set to rivers and oceans, and in growing rapidly rarer 

 as we ascend. All these features are favorable to the development of direct 

 currents or whirlpools, and the same originating cause would produce greater 

 motion in air than in water. 



The conception of the winds is still farther simplified if we imagine them 

 moving in sets or systems, the whole set having an independent progressive 

 motion. A dust-whirlwind is a system of winds. The whole set of winds may 

 remain stationary as a system or may have a progressive motion. If the latter, 

 and we stand in its path, the wind which strikes us may be first north and 

 then south, while the whirlwind as a whole may come from the east. The 

 direction from which the system of winds comes does not necessarily indicate 

 the direction of the currents forming the system. 



There are three different systems of winds known, the parallel, the cen- 

 trifugal and the centripetal. In the parallel system the currents which make 

 it up move parallel to each other, and the whole may be called a river of air. 

 In this case the direction of the current which reaches us indicates the direc- 

 tion from which the system comes. Very few of our winds belong to this 

 class. It is illustrated by the straight zephyrs of summer, and also by the 

 trade and anti-trade winds. When the parallel winds are of little extent they 

 are straight-lined, but when they pass over a considerable part of the distance 

 between equator and poles, the rotation of the earth bends them. Thus the 

 trade wind bends in its course from north to nearly east and the auti-trade 

 from south to nearly west. 



In the centrifugal system, the wind pours out in all directions from a centre, 

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