198 Miscellanies. 



letters which were written before the second fusion will be found 

 entire. The experiment may be repeated many times, and the 

 metal may even be shaken while in fusion, and the characters traced 

 upon the metallic surface will always be found again. The phe- 

 nomenon seems to be caused by the circumstance, that this surface 

 is formed of a very thin coating of oxide, like a pellicle, which does 

 not become fluid with the metal. — Bib. Univ. Feb. 1833. 



METEOROLOGY. 



16. Use of the Barometer at sea. — Mr. Clarence Dalrymple, cap- 

 tain of one of the East India Company's ships, in his "Historical Ac- 

 count and Description of British India," (Edinburgh, 1832,) men- 

 tions the use of the marine barometer as one reason of the present 

 short voyages between England and India. A vessel may now make 

 a voyage out and home in eight months, which fifty years ago requir- 

 ed twelve months. Formerly, to avoid injury from squalls at night, 

 the sails were all single and even double reefed, at sunset. 



Now by the use of this instrument, the observer, who follows its 

 motions, may carry as much sail at night as by day, regarding also a 

 principle of navigation, i. e. to brail up the sails in time before a 

 squall, but to be prompt to spread all sail as soon as the chief vio- 

 lence of the storm is past. 



Capt. D., in speaking of the navigation near the Cape of Good 

 Hope, says, "in no part of the world are the indications of this pre- 

 cious instrument more faithful than in the regions of the Cape. 



"A rapid descent of the mercury indicates, with certainty, gales 

 of wind from the north west, and often even in a perfectly still time. 



" Such a warning ought never to be disregarded. In the southern 

 hemisphere, the mercury rises with south winds and falls with north 

 winds. During light breezes from the south east, after a storm, it 

 generally ranges high, and a considerable descent takes place when 

 the wind shifts to the north east, though there should be no gale. 



" This depression is owing to a change of temperature, the north 

 winds being warmer than those from the south, which come from 

 the icy regions of the south pole. If the mercury continue to fall 

 after a southern breeze is established, a more powerful wind may, 

 with certainty, be expected. 



" During the most powerful storm the author ever experienced 

 near the Cape, the barometer descended to 28.98 English inches." — 

 Bib. Univ. Feb. 1833. 



