THE AMERICAN STORM OP DECEMBER 20, 1836. 3 



synopsis of the results was published in 1840, as a part of my first paper above 

 referred to. This examination did not favor tlie supposition of any intimate con- 

 nection between the American storm of December 20th and the European storm 

 of December 25th ; nevertheless, the observations were too few in number to indi- 

 cate all the phenomena of the European storm. During a visit to Europe in 1850 

 and 1857, 1 improved the opportunity to collect additional observations for Decem- 

 ber, 18-36, and succeeded in obtaining barometric observations from twenty-five 

 additional stations, besides a few registers which were deficient in observations of 

 the barometer. Having projected these observations upon a scries of maps in the 

 manner described with reference to the storm of February 4, 1842, 1 perceived that 

 the phenomena of this storm were very remarkable, differing in some respects from 

 any which I had previously seen investigated, and I then resolved to make a further 

 effort to obtain materials for rendering the investigation in all respects complete. 

 I accordingly addressed letters to twenty-five meteorologists in dift'erent countries 

 of Europe, soliciting copies of their journals for the period in question. In answer 

 to these letters I have received observations from twelve additional stations, so tliat 

 now I have barometric observations from forty-seven stations, extending over nearly 

 every country of Europe. I propose to present a summary of these observations, 

 after first examining the American storm. 



AMERICAN STORM OF DECEMBER 20, 183C. 



Observations of the Barometer. 



The following table presents a summary of the observations of the barometer at 

 each of the American stations : column first shows the name of the station ; columns 

 second and third their latitude and longitude; and column fourth the mean height 

 of the barometer at each station. The numbers in this column have been derived 

 in the following manner : For all those stations where there has been made a series 

 of observations extending over several years, the mean of this series, whenever it 

 could be ascertained, has been inserted in column fourth. For the remainuig 

 stations the assumed mean height is that due to the supposed height of the station 

 above the sea, corrected in some cases by comparison of the observations made 

 simultaneously at neighboring stations where the mean heiglit of the barometer 

 was pretty well determined. The fluctuations of the barometer were required for 

 S A. M. and 8 P. U. of each day; and whenever these hours did not correspond to 

 the actual hours of observation at any station, the height for these hours was 

 interpolated by a comparison of the preceding and subsequent observations. 1 he 

 numbers thus obtained were diminished by the mean height of tlie barometer tor 

 that station, and the remainders are inserted in columns five to twelve ; which 

 accordingly show how much the barometer was above or below its mean height for 

 the dates given at the top of the table : — 



