LABORS OF THE JOINT COMMITTEE. 79 



hot summer day : as these clouds are frequently formed be- 

 tween two currents, their tops will lean in the direction of 

 the upper current, and, indeed, sometimes be blown off and 

 dissipated, in a direction different from the air below. 



We also particularly request, that if you hear of any 

 storms occurring in your neighborhood, you will collect all 

 the information concerning them in your power. 



Particularly inquire the course of the wind at the com- 

 mencement of the storm and at its termination ; the width 

 of the storm ; its direction ; its velocity ; the direction of the 

 wind at its sides; how the wind veers round whether in 

 different directions at its sides or not ; whether, in case of 

 hail, there are two veins or only one ; where there is the 

 greatest fall of rain, near the borders or near the centre of 

 the slorm and whether this fall takes place near the be- 

 ginning, middle or end of the storm ; whether the clouds 

 are seen moving with the wind or against it, and whether 

 differently among themselves ; and every thing else which 

 you think may tend to an explanation of this most inter- 

 esting phenomenon. 



Let the time of beginning and end of all rains be particu- 

 larly noted, any change in the strength and direction of the 

 wind during their progress, and the quantity as near as 

 possible. Mark the time of meteors, or shooting stars, and 

 auroras, and if possible the stars through which they pass. 

 These observations, if made by very many correspondents 

 throughout the United States, will elucidate the main object 

 which the committee has in view in the present circular, 

 and it is hoped greatly assist in giving interest and value 

 to the plan in contemplation. But as many observers may 

 be willing to do more, we will remark that the observations 

 on storms will be much enhanced in value, if accompanied 

 by observations on the " dew point :" for it may be, that 

 hurricanes never occur only when the dew point is high. 



A very simple as well as accurate method of taking the 



