100 ANNUAL KECOliD OF SCIENCE AND INDUSTRY. 



twelve generalizations in reference to diurnal temperature 

 changes. Among the conclusions he deduces from these, we 

 note that he deems it entirely premature to elaborate any 

 formula for the connection between the diurnal period and 

 its apparent physical causes, the solar radiation, atmospher- 

 ic diathermancy, soil, winds, clouds, etc. Elaborate tables 

 for the reduction of observations made at various hours to 

 the true daily and annual means conclude this first portion 

 of Wild's important work. The expense of compiling these 

 tables has been borne by the minister in charge of the crown 

 lands. 



Tables of mean annual temperatures for numerous points 

 in Colombia and Ecuador arc published by Reiss and Stiibel 

 in the tables of altitudes determined by them in those coun- 

 tries. 



The twenty-five years of unbroken observations from 1848 

 to 1872, at twenty-nine stations in Germany, have been, by 

 Hellmann (Zeitschrift K. P. StatistiscJien Bureaus, vol. xv., 

 p. 405), made the basis of an inquiry into the Variability of 

 the Temperature in Northern Germany. The highest mean 

 variability occurs in Eastern Prussia; the least variable cli- 

 mate is that of the northern coast of the Baltic. The aver- 

 age variability of the summer months is only half that of 

 the winter months. The most variable month is February; 

 the reason of which is found, by Hellmann and Dove, in the 

 fact that at that time the waters of the Arctic regions are 

 still frozen up. A highly suggestive table gives the number 

 of years necessary to be employed in order to obtain a mean 

 that shall have an accuracy of one tenth of a degree, whence 

 it appears that three hundred years of observations would be 

 needed to obtain this accuracy in the mean for the most va- 

 riable month, or February. 



Hann has communicated to the Academy of Sciences of 

 Vienna a memoir on the Temperature of the Air observed 

 at that place during the last hundred years, in which work 

 he has simply completed a task left unfinished by Jelinek. 

 lie investigates the secular change and the annual changes, 

 and especially the relation between the temperature and the 

 sun-spots, in reference to which latter subject he concludes 

 that the influence of the sun-spots upon the mean tempera- 

 ture is so slight that within any given eleven-year cycle it is 



