SECRETARY'S REPORT. 221 



" 1. When the mercury is very low, high winds and storms are 

 likely to prevail. 



2. Generally, the rising of the mercury indicates the approach 

 of fair weather ; and its flilling shows the approach of foul weather. 



3. In sultry weather the falling of the mercury indicates thun- 

 der. In winter its rise indicates frost. In frosty weather its fall 

 indicates thaw, and its rise indicates snow. 



4. Whatever change of weather suddenly follows a change in 

 the barometer, may be expected to last but a short time. 



5. When the barometer alters slowly, a long succession of foul 

 weather may be expected, if the column falls, or of foir weather if 

 it rises. 



6. A fluctuating and unsettled state of the barometer, indicates 

 changeable weather. 



In the above rules the index hand of the Aneroid answers to the 

 mercury column of the old barometer." 

 . Mr. Kendall furnishes the following rules : 

 " 1st. There is no point at which the barometer must stand to indi- 

 cate rain or wind. 



2d. The judgment must be governed by the rising or falling of 

 the barometer. 



3d. The falling of the barometer indicates the approach of a storm, 

 the extent of which will be proportionate to the amount and rapid- 

 ity of the fall. 



4th. Showers. The barometer falls previously from four to 

 twelve hundredths of an inch, varying in time, from one to three 

 hours. The greater and more rapid the fall, the more violent will 

 be the shower, accompanied more or less with wind. 



5th. Northeasterly storms. The barometer falls previously from 

 four to eight-tenths of an inch, vaiying in time from one to four 

 hours, and continues falling until the storm arrives at its crisis, 

 when the barometer begins to rise and continues rising until that 

 part of the storm which comes from the N. W. passes off. 



6th. Southerly storms. The barometer falls previously from one 

 to four-tenths of an inch, varying in time from six to twelve hours. 

 These storms generally precede unsettled weather ;*at such times 

 the barometer continues low, and very slight additional depressions 

 are followed by rain. 



A southerly storm is perhaps the most difficult to judge of by 

 appearances, as they change so frequently without any real change 

 in the atmosphere. During this class of storms, the utmost confi- 



