ABOUT THE 20tH OF DECEMBER, 1836. 145 



they were, which produced the oscillation, were now acting with diminished 

 energy. The diminution was about one-half in less than two days. It might 

 naturally be expected that the wave would go on diminishing until, by its in- 

 significance, it should become insensible. What law this diminution would 

 observe we are unable to say. For the sake of an estimate, however, let us 

 take a simple supposition. The loss was one-half in two days. In two days 

 more the last range might be reduced one-half; and again one-half in two days 

 more. That is, in four days from St. Johns, the range would be in latitude 

 32°, 0.11 inch; and in latitude 47°, 0.22 inch, a fluctuation too small to be 

 traced with confidence. At the rate with which the wave travelled from Hali- 

 fax to St. Johns, in four days more it would have passed somewhat beyond the 

 Azores. But it will be observed that the velocity of the wave was sensibly re- 

 duced in travelling eastward. It had even become reduced to about one-half 

 in two days in the latitude of Quebec. We might then expect the wave would 

 become insensible before it reached the middle of the Atlantic. 



But a remarkable storm was experienced over nearly the whole continent of 

 Europe, about the 25th of December, and the opinion has been repeatedly ex- 

 pressed that this storm was identically the same with the one whose pheno- 

 mena I am investigating. With the view of prosecuting this inquiry, I have 

 collected all the European meteorological registers of this period in my power. 

 Observations made at St. Petersburgh and Catherinenburgh were obtained from 

 the library of the American Philosophical Society, by the politeness of Mr. 

 Vaughan, and copied for me by Mr. S. C. Walker. The latter place is in lati- 

 tude 56° 50' N., and longitude 60° 35' E., and is eight hundred and thirteen 

 English feet above the level of the sea. Observations for Brussels and Milan 

 were furnished me by Mr. S. C. Walker, the latter being from the library of 

 the High School Observatory in Philadelphia. The observations for Geneva, 

 Zurich, and St. Bernard, were from the Bibliotheque Universelle, and copied 

 by Mr. E. 0. Herrick: those for London, Chiswick, and Boston, are from the 

 London and Edinburgh Philosophical Magazine: those for Paris, from the 

 Comptes Rendues des Seances de 1' Academic; and those for Cadiz, in Spain, I 

 obtained through our consul, Mr. Burton. The barometric observations I have 

 projected in curves on Plate 2, a difference of an inch in the ordinates of 

 the curves representing an oscillation of the barometer to the same amount. 

 A bare inspection of this chart is sufficient to show that there were, at this pe- 

 VII. — 2 M 



