Mean Direction of the Wind. 241 



here 20 miles in breadth, is distant only ten miles. It is presumed 

 that the temperature liere given for the .Vtlantic Oeean would not 

 diifer greatly from the temperature of Long Island Sound for the 

 corresponding mont hs. 



Near tlie parallel of 40° N. lat. the average wind is from a point 

 a little South of West. We will call this the normal wind, and 

 inquire whether the temperatures shown in Table VI, will enable us 

 to explain the departures from this normal direction shown in the 

 observations at Wallingford. Beginning with the month of January, 

 we iind the temperature of tlie land, even at its maxinnnn, to be 

 many degrees lower than the neighboring water. This cause should 

 then produce a deflection of the normal wind in the direction from 

 the land toward the water ; and this should continue throughout the 

 24 hours, but should be most decided during the colder half of the 

 day, which conclusion corresponds very closely with the ol)served 

 facts. The same remark is applicable to the mouth of P^ebruary, 

 except that during the warmest j)art of the day, the temperature of 

 the land difl:ers from that of tlie ocean less than in January, and the 

 deflecting force should be less ; which conclusion also corresponds 

 very well with the observed facts. The phenomena for January and 

 February are therefore \ ery well explained by the unequal tempera- 

 ture of the land and the neighhoring water, without ascribing any 

 influence to the more distant and warmer water of the Gulf Stream. 



P^or the month of March, the same remark is applicable during the 

 colder half of the day ; but about the hour of maximum heat the 

 temperature of the land and that of the neighboring water is about 

 the same, while observation shows the wind still tending fi-om the 

 northwest. Tins would seem to indicate tliat the heat of the Gulf 

 Stream was the principal deflecting force; but perhaps the facts may 

 be explained from the inertia of the air set in motion from the iKjrth- 

 ward, because the neighboring water is warmer than the land 

 during nearly the entire day, and the slightly higher temperature of 

 the land continuing but for an hour or two, is iiisiitticient to arrest this 

 steady current from the north. The phenomena for March are easily 

 explained by reference to the higher tempei'ature of the Gulf Stream ; 

 and may, perhaps, be explained without ascribing any very important 

 influence to this more remote body of water. 



During the month of April, the mean temperature of the land is 

 higher than that of the neighboring water ; and even at the coldest 

 houi- of the day, the land cannot be much colder than the water. 

 Nevertheless, observations show a strong deflecting force from the 



