571 



the least impulse, if time be given, but presents great resist- 

 ance to any rapid movement. The two reduce the excursions 

 three-fourths. But he thought it vrould not be desirable to 

 remove them entirely, even if possible, because he has found 

 that this is a distinctive character of some winds, independent 

 of their force. It is always connected with a tempestuous 

 roar, which gives an exaggerated impression of their force ; 

 and some of the heaviest gales he has observed were compa- 

 ratively noiseless. He then showed three of the sets of dia- 

 grams; one, of April 18th, the day of the storm which did 

 such damage in Dublin, had nothing remarkable, except that 

 from 3 to 5 there was a great change of direction to the 

 eastward, and return to the original point, with a sort of un- 

 steadmess that seemed to mark some struggle. The second 

 was a gale on December 15, 1848, in which 516 miles in 

 twelve hours were recorded. In the hour from 2 to 3, 

 gixty-one miles were passed ; and dxuing two minutes and a 

 half of it the velocity was at the rate of 105 i miles per hour. 

 This was a cyclone, or ch'cular storm. But a stiU finer speci- 

 men of that was afforded by the third, in wliich 380 miles in 

 twelve hours was marked, but the direction changed nearly 

 through two entire cu-cumferences. 



He should have detailed the mode of combining the re- 

 sults thus obtained ; but he felt he had already trespassed too 

 long on their patience. He thanked the Academy for their 

 indulgence, but referred it to the interest which they took in 

 whatever tended to advance physical inquiry. He did not 

 fear to be met by any body guided by such a President, much 

 less by the Eoyal Irish Academy, with the utilitarian question, 

 " Of what use is all this ? " " Even on that ground we might 

 encounter an objection. If, as in the case of the tides, we 

 succeed in working out a theory of the winds, it would have 

 a high commercial value. And why not ? We know many 

 of their causes, the temperature, the vapour, tension, the 

 electricity of the atmosphere. We want only the anemome- 



