LAND AND SEA BREEZES. 105 



ing and healtliM by the alternation of winds which come from the 

 sea by day, and from the land by night. About ten in the morn- 

 ing the heat of the sun has played upon the land with sufScient 

 intensity to raise its temperature above that of the water. A por- 

 tion of this heat, being imparted to the superincumbent air, causes 

 it to rise, when the air, first from the beach, then from the sea, to 

 the distance of several miles, begins to flow in with a most de- 

 lightful and invigorating freshness. 



231. When a fire is kindled on the hearth, we may, if we will 

 observe the moats floating in the room, see that those nearest to 

 the chimney are the first to feel the draught and to obey it — they 

 are drawn into the blaze. The circle of inflowing air is gradually 

 enlarged, until it is scarcely perceived in the remote parts of the 

 room. Now the land is the hearth, the rays of the sun the fire, 

 and the sea, with its cool and calm air, the room ; and thus we 

 have at our firesides the sea-breeze in miniature. 



232. When the sun goes down the fire ceases ; then the dry 

 land commences to give off its surplus heat by radiation, so that 

 by nine or ten o'clock it and the air above it are cooled below the 

 sea temperature. The atmosphere on the land thus becomes heav- 

 ier than that on the sea, and, consequently, there is a wind sea- 

 ward which we call the land-breeze. 



233. Jansen thus describes this phenomenon in the East In- 

 dies, where one must live fully to appreciate its benign influences. 



234. Jaxsen's Account.* — "A long residence in the East In- 

 dian Archipelago, and, consequently, in that part of the world where 

 the investigations of the Observatory at Washington have not ex- 

 tended, has given me the opportunity of studying the phenomena 

 which there occur in the atmosphere, and to these phenomena my 

 attention was, in the first place, directed. I was involuntarily led 

 from one research to another, and it is the result of these investi- 

 gations to wliich I would modestly give a place at the conclusion 

 of Maury's Physical Geography of the Sea, with the hope that 

 these first-fruits of the log-books of the ^Netherlands may be 

 speedily followed by more and better. 



*^ Jansen's Appendix to the Physical Geography of the Sea, translated from the 

 Dutch by Mrs. Dr. Breed, Washington. 



