802 =O. T. Sherman—Height of Land and Sea Breezes. 
land breeze. The sea breeze blows perpendicular to the coast, 
or about southeast. To obtain the storm wind, I examined 
the 7°35 A. M. maps of the Signal Service, but since the obser- 
vations were taken almost directly under areas o 
pressure, the examination gave no useful results. I therefore 
adopted a method based upon the following considerations. 
Of all those directions and velocities which combined with the 
direction of the sea breeze can produce the resultant, the storm 
breeze is that which remains when the sea breeze vanishes; 
the fact that the sea breeze vanishes is shown by the other 
component remaining undisturbed. For example, on August 
13, the observed wind was S.S.E., velocity 7:5 miles. This 
might be produced either by S. 45, SH.; SSW.4,SE, 
S.W. 3, S.E., etc., but of these, S.W. 8 most nearly satisfies 
the condition that it shall be observed by itself. The surface 
breeze therefore ends at about 650 feet from the surface of the 
sea, while above 700 feet a current from the land evidently de- 
flects the breeze toward the northwest. Proceeding with each 
of the other cases in the same way a mean may be taken. In 
this manner we have drawn up the following table. The values, 
though necessarily approximate, gain much from our inability 
to launch the balloon save on calm days. The sign << implies 
that the given value is probably too high. 
Day. Honk Surface breeze _ Return breeze 
ends, begins. ends. 
1879. h oe 
July 31)10 15 am <175 feet. <400 feet. 
2 46 p.m! <500 feet. About 750 
7 26 P.M.) <875 feet. <400 feet 
August 1; 9 46 a.m 200? feet. <300? feet. 
10. 54 am bove the highest | point reached. 
2; 9 0 aA.M.| <200 feet. <250 feet. 
1 65 P.M! <2200 feet. <600 feet. 
10} 1 19 P.M.| <400 feet. <500 feet. < 900 feet. 
3 10 P.M.| <(500 feet. 500 feet. <1100 feet. 
5 42 PM one. 
Ta oe IO Bet <825 feet. <900 feet. 
12; 10 50 a.m.) <600 feet. <800 feet. 
13} 11 60 a.m) <650 feet. | 700 feet. | 1050 feet? 
14, 1 42 pm| <300 feet, <A00 feet. 
