N. MISCELLANEOUS. 597 



N. MISCELLANEOUS. 



COMMUNICATIONS TO THE SOCIETY OF PHYSICS AND NATUEAL 



HISTORY OF GENEVA. 



Among first-class institutions devoted to scientific research 

 in Europe, the Society of Physics and Natural History of Ge- 

 neva has always borne an honorable part, its publications 

 containing material in all branches of science of the utmost 

 value. The last volume of the memoirs embraces the usual 

 summary by the president of the papers presented to the so- 

 ciety, in this instance for the year extending from June, 1869, 

 to June, 1870. Among the more important of these are the 

 following : A memoir by Professor De la Harpe upon the the- 

 ory of numbers, in w T hich he shows that cubes have a common 

 measure among themselves. Professor Schaix gives a con- 

 jectural map of the region of Central Africa indicated by Liv- 

 ingstone as containing the source of the Nile. Professor Plan- 

 tamour reports upon the results which had been accomplished 

 by himself and Professor Hirsch in connection with the geo- 

 detic survey of Switzerland. Professor Gautier discusses the 

 observations made by the Moravian missionaries upon the 

 coast of Labrador, where the thermometer ranges from a very 

 low temperature in winter to quite a high point in summer. 

 M. Risler, in the course of experiments upon evaporation from 

 the soil, ascertained that during the years 1867 and 1868 about 

 seventy per cent, of the amount of rain which fell w r as passed 

 off annually by evaporation. M. Forel, in a somewhat similar 

 investigation, discovered that the Rhone furnished a larger 

 amount of water than could be supplied by the rain-fall of 

 the country, and concluded that the excess was derived from 

 the direct condensation of the moisture of the atmosphere 

 upon the glaciers and the snow-fields of the mountains. M. 

 Forel also suggests an ingenious method of obtaining the tem- 

 perature at the bottom of lakes, namely, by drawing up a 

 quantity of mud and testing its temperature immediately, the 

 degree ascertained being sufficiently near that of the water 

 itself at the bottom to answer all purposes. 



Numerous communications were made in reference to the 



