[26°], — 
-edaae ‘ohte: aie METROROLOGICAL TABLES ~ 
Ares papreperea from my meteorological journal, kept on the road. Some 
of the columns may require an explanation. : 
The column “ boiling point of water,” refers to my observations with ° 
two thermometers, constructed by my order, b by J. W. Edmonds, of Boston, 
each varying from 85 to 100° Celsius, and every degree divided i in tenths. 
made many experiments with them on the road, to find the relative dif- . 
ference Aa the boiling point of water and the mercurial column of ’ 
my barom From about 50 such observations, made within the range 
of from 23 ss 29 Rictivs of the barometer, I abstracted the general result, 
that 1 inch of my barometer at the temperature of 32° Fahr., was = 
1°.04138° boiling point Therm. Cels., and 1° Th. C. = 0". 96026 of the 
barometer. But, at the same time,'I have come to the conclusion, as — 
others before me, that the determination by the boiling point of water 
can never in correctness equal the barometrical measurement. A differ- 
ence in fuel, in water, in the size of the vessel, in draught of air, &c., is 
apt to produce such a discrepancy in the relative boiling point, that © 
_ ~ this method will answer well enough as a correlative eee a +5 aie 
ter, and for heights, where several hundred feet, m 
matter of consideration, but that it will never be caabts of sippy oe 
place of a barom 
3 w-point, mend by excess of temperature of the dry over the wet 
bulb, is Salculated according to “tables for the determination of the dew- 
point, ” siven in the Encyclopedia Britariica, and republished in the 
“Report to the Navy Department of the United States on American coals, 
by Professor Walter R. Johnson: Washington, 1844.” Observations be- 
yond the reach of these tables, I calculated according to the rule given 
by Professor Espy : “The dew-poiit, when it is not very low, may be 
nearly obtained by multiplying the difference between dry and: wet bulb 
temperature with 103, dividing the result by the wet-bulb temperature, 
and subtracting the quotient from the dry-bulb temperature; the remainder 
will be the dew point.” 
In the colunin “ wind,” the force of the wind is sal gt as recom- 
mended by Professor Espy, by numbers from 0 to 6; 0 being a calm, 1 
avery gentle breeze, 2a gentle breeze, 3a fresh wind, A a Strong wind, | 
5 a storm, and 6 a hurricane. 
clearness of the sky is also marked in numbers from 0 to 10; 0 
Tepresenting entire cloudiness, and 10 entire clearness. 
