PEOGRESS OF METEOROLOGY IN 1880. 266 



transferred to cold regions where it is cooled by condactiou of its beat 

 to the cold surface. 



In comments on this paper Professor Ferrel accepts the fact of the 

 heating- of the air by conduction and by convection as outlined by Mr. 

 Searle, but thinks that this circumstance can not have much effect in 

 modifying terrestrial temperature. "The whole amount of heat con- 

 veyed away froTu the earth's surface in the form of" latent heat, is per- 

 haps one-tenth of that received from the sun and absorbed, and so 

 radiated again into space. If this one-tenth part only has a little less 

 facility for escaping into space than it would have if radiated directly 

 from the earth's surfiice, the protective effect can not be very much." 

 In fact the primary assumption that the earth's mean temperature 

 would be much lower than it is, if it were not protected in some way by 

 the atmosphere, is by no means certain. {Am. Meteor. Journal, vi, p. 173.) 



Decrease of temperature with hek/ht. — Dr. Ilann, in a discussion of the 

 results of observations on the Sonnblick, derives some important form- 

 ulie expressing the decrease of temperature with height. For yearly 

 means he linds that thi^temperature at any elevation is represented by 

 the formula T=S°.0-0^.4:62h'—{)o.ooiSh'\ in which /(/ is the height of the 

 station above Salzburg (450 meters) expressed in hectometers. This 

 equation shows that the true mean temperature of the air column be- 

 tween the snmmit and base is O'^.S higher than the arithmetical mean of 

 the temperature at the summit and base— a result of great importance 

 in practical hypsometry. For the different seasons the formuhe for 

 decrease of temperature are as follows : 



Winter : T^ -2 .1 —0.136//' — O.OUl/*/^ 



Spriug : T= 7.1 — 0.5377(' — 0.0011/i,"^ 



Siinimer: T= 18.0 — 0.(3377<' 



Antumu: T= 9.7 — 0.4337(' — 0.003i;;/2 



{Meteorologische Zeitsckrift, 1889, vi, p. 33.) 

 Mr. S. A. Hill has conducted an extended series of observations of 

 temperature and humidity at different heights above ground at Allaha- 

 bad, and the results are published in Vol. iv. Part vi, Indian Meteoro- 

 logical Memoirs (see Bibliography). From observations at heights of 

 4, 4G, 104, and 160 feet, the daily range of temperature was found to 

 diminish with altitude at a rate represented by the formula 



log. r =1.324 -0.118/j -f 0.023/^2 

 in which /i is given in hundreds of feet. The formula can be extended 

 scarcely 100 feet beyond the observed values. Normol hourly temper- 

 atures for each month of tlie year arc given for each of the four eleva 

 tions, and from these the temperatures for altitudes of every 20 feet up 

 to 200 feet are given for G A. m., 2 p. m., and 10 p. m. for each month and 

 the year. The results of the observations are also graphically repre- 

 sented by contours giving for every 5° the variations of temperature in 

 the diurnal i)eriod at different heights. Thirteen such sets of isother- 

 mal contours give the means for each montli and the year. The obser- 

 vations of vapor pressure show a minimum from 3 to 4 p. m., followed by 



