TABLES OF TEMPERATUEE. 119 



tables is much to be regretted, as this would have led to a toler- 

 ably correct estimate of the decrement of temperature due to 

 elevation in the respective parallels of latitude. As it is, the 

 places being arranged according to their latitudes, the contrast 

 thus afforded between the temperatures of places known to be 

 near the level of the sea, and those at ascertained elevations 

 where such occur on nearly the same parallel, will doubtless 

 prove interesting and useful. 



The following tables have been drawn up from the Tempera- 

 ture Tables of Professor Dove, of Berlin, published in the 

 Report of the British Association for the Advancement of 

 Science, and from other sources. They exhibit the mean tem- 

 perature of the months, the mean temperature of the seasons, and 

 of the whole year, the difference of the hottest and coldest months, 

 and that of summer and winter, the number of years in which 

 the observations have been made, and the hours of observation. 

 The seasons are according to the meteorological divisions of the 

 year : winter including the months of December, January, Feb- 

 ruary ; spring, those of March, April, May ; summer, June, 

 July, August ; and autumn, September, October, November. 

 In the column showing the hours of observation, the letters 

 N.Y. indicate that the observations have been reduced by the 



- , ^-. ^^ a + 2b + 2c + a' . , . , 



lormula JN. 1 . = , in which a is the observation 



o 



at 6 A.M., 6 at 3 p.m., c at one hour after sunset, and a' at 6 a.m. 

 the following day ; that is, the temperature observed at 6 a.m., 

 twice the temperature at 3 p.m., twice that at one hour after 

 sunset, and the temperature at 6 a.m. the following day, are 

 added together and divided by 6 for the mean temperature of 

 the twenty-four hours. In other cases, marked " Red.," the obser- 

 vations at particular hours have been reduced to the mean by 

 Bessel's formula. It would have been very desirable, for the 

 sake of comparison, if all the results had been uniformly reduced 

 to the true mean temperature ; but the best formulae to be ap- 

 plied for different countries have not yet been fully agreed upon. 



K 2 



