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Miscellaneous Intelligence. 



and disappearance without long-continued and varied observations. Yet* 

 from the marked contrast in respect to moisture, and other properties be- 3 

 tween our great continental and our oceanic winds, it seems not improba- 

 ble that some such opposite relations to ozone as above indicated may be 

 found actually to obtain. 



3. The Tides at Ponape, or Ascension Island of the Pacific Ocean — 

 lat. 6° 55' N, long. 158° 25' E ; by L. H. Gulick, M.D., (communicated 

 for this Journal.) — This island rests under the opprobrium of seamen 

 for having tides scarcely at all conformed to those of other lands, and 

 governed by no apparent laws. It is easy however to prove that the 

 tides of Ascension Island conform more nearly to the requisitions of the 

 Newtonian theory than those of many other portions of our globe. 



I would first direct attention to the fact that this island is situated far 

 from any body of land, or even of extended reef, which might have de- 

 flecting and perturbing influences on the tidal waves. A glance at the 

 map, shows that the few coral groups, east aud west, could not have as 

 much effect on the tide waves of this part of the ocean as so many posts 

 set up in the channel of the Mississippi would have on the current of that 

 river. True, each post would create its own immediate ripples and slight 

 eddies ; but the pouring flood would not thereby be in the least affected. 

 This " Micronesian" portion of the Pacific, extending from the Mille Isl- 

 ands to Pelew, has to the East of it the most extended open ocean in the 

 whole circumference of the globe, with the exception of a line in the 

 Southern Hemisphere ; so that if the tides ever conform to the attractive 

 powers of the sun and moon, they should here. 



It is interesting also to notice the fact that the natives of this island 

 know well the tidal laws, (though, of course, not their rationale) and by 

 the appearances of the moon can determine before hand all the most 

 important changes it undergoes ; and that they have also many fixed 

 terms for the different times and depths of tide. 



In accordance, therefore, with the usual law, our spring tides come at 

 the syzygies. The tides in general lag about 30° behind the time of the 

 luminaries' reaching their meridians. At the full and change, the tide is 

 invariably highest at about 2 o'clock of morning and evening — which 

 is therefore the " Establishment" for this island. When the moon is in 

 quadrature we familiarly say we have " half tides", with but little varia- 

 tion, though there is always a small lunar tide at about 8 a. m. or p. m., 

 and often there are several slight perturbations in the course of a few 

 hours, that seem anomalous, but can well be referred to the various acci- 

 dental causes from winds and currents that may readily affect the waters 

 while other influences upon them are so nearly neutralizing each other. 

 As usual, every alternate tide is the highest ; — in summer, when the sun 

 is in northern declination, the night tides are the largest, and in winter, 

 the day tides. The height of the highest spring tides is about five feet. 



The presumption is very probable that the tides are equally uniform 

 through the most if not all of the Micronesian Islands. It is much to be 

 desired that reports should be made and published by the intelligent mis- 

 sionary observers now occupying several points in these ranges, so that 

 we may soon have an accurate map of co-tidal lines for Micronesia, if 

 not for Polynesia and all Oceanica. 



