Meteorological Observations. 377 



in naming shells, even when they succeed in establishing their 

 claims, will acquire no lasting reputation, unless they show they 

 have studied the animals too. We mean no offence in our re- 

 marks to any one. Several of the most conspicuous conchologists 

 of this country. Say, Barnes, Lea, and others, have made import- 

 ant remarks on the structure and habits of the mollusca ; but at 

 present the general pursuit appears to be after the shadow, 

 rather than the substance ; and we regret it both for the sake of 

 zoology and for the sake of our conchologists. 



METEOROLOGICAL OBSERVATIONS, 

 Made at Wilmington, Delaware, by Henry Gibbons, M.D. 

 Summary for December, 1881. 



Proportion of clear weather, days 18 



Proportion of cloudy, 13 



Whole days clear, 12 



Days on which rain fell, 1 



Days on which snow fell, 8 



Quantity of rain, in. 2 



Depth of snow, 6.75 



Of water,'*^ 2.10 



Northerly winds prevailed, days 16 



Easterly, 6 



Coldest day, 16th, 6J°. Southerly, (S. to W.) 9 



Auroras, none. The month rather dry : snows frequent, but not deep ; 

 rain fell only once, and then in very small quantity. Temperature uni- 

 formly cold ; much below the usual standard for this month. The thermome- 

 ter was above the freezing point at sun-rise on one day only, and at noon 

 on nine days. (See the review of the year.) Winds occasionally hig-h, and 

 mostly unsteady, flowing- from no one quarter of the compass so long as two 

 successive days, except on two occasions. No electrified clouds. Four easterly 

 storms, three of them with snow, the other dry ; none of them severe. 



Therm. Barom. 



Average at sun-rise, 19°.39 m.29.83 



Average at mid-day, 28°.94 29.76 

 Average at 11 o'clock, 



P. M. 20°.77 29.77 



Monthly average, 24°.16 29.795 



Maximum, 21st, 41°. 30.20 



Minimum, 16th, 0°. 29.23 



Range, 41°. 97 

 Warmest day, 24th, 351°. 



" 6|° 



General Review of the Weather for the year 1831. 



The last month of 1830 was mild, and the weather continued 

 open till the 9th of January, 1831, when winter set in with a 

 storm of sleet and snow, from N. E. This was followed by the 

 memorable snow-storm which commenced on the evening of the 

 14th, and terminated at noon on the 16th, after a duration of 

 42 hours, exceeding in violence any thing that had before oc- 



* Nine inches of light snow are equivalent to one inch of water ; the propor- 

 tion, however, varies with the character of the snow. 

 Vol. L— 48 



