186 



Miscellaneous Intelligence. 



inches above the earth. It was examined every morning at sun- 

 rise: if it contained dew, the liquid was carefully introduced into a 

 phial of known weight, and weighed ; the portion adhering to the 

 moistened surface was estimated, from the results of many ex|,eri- 

 ments, at 30 grains, and added to the weight of that in the bottle. 

 If the drosometer, as the instrument was called, was merely moist- 

 ened so as not to run with fluid, the quantity was estimated at 30 

 gr. ; if it was less, an estimation was made, as nearly as could be 

 done, by judging of the quantity. The weight once ascer- 

 tained, it was compared with a table constructed from the weight 

 of a known column of water, of equal diameter with the instrument, 

 by which means M. Flaugergues thinks it is easy to ascertain the 

 thickness of the coat of dew to the„y'o^ of a line. 



As an instance of the use of this instrument, the quantity of dew 

 and rain which fell in 1823, and the number of days on which it 

 fell, is given as follows : — 



DEW. RAIN. 



2.901 125 442.81 132 



The rain is to the dew as 152 1 to 1. March was the month in 

 which the least dew fell. October the month in which the most 

 was deposited. 



M. Flaugergues puts but little confidence in these experiments 

 and observations as yet, but they seem to give some general ideas 

 on the quantity of dew deposited. He is continuing the experi- 

 ments with drosometers made of various substances ; and many 

 other precautions will be suggested by the knowledge of dew fui^ 

 nished to us by Dr. Wells. — Bib. Univ. xxv. 261. 



3. Rain-Oauge. — M. Flaugergues has two rain-gauges, one 

 placed on the top of an observatory, and the other in a court-yard 

 beneath. During the year 1823, 36 inches 10.81 lines of rain fell 

 into the first, and 39 inches 5.4 lines into the second. This excess 

 in the lowsr rain-gauge has been constantly observed; and the 

 observation of six years gives the ratio of the two quantities as 19 



