F. GEOGRAPHY. 231 



F. GEOGRAPHY.* 



ANEROIDS AND HYPSOMETRY. 



In a supplement to the Meteorologia lialiana^ Dr. Grassi 

 gives the results of experimental research upon aneroid ba- 

 rometers. His aneroids were compared with standard mer- 

 curial barometers, both during journeys to high mountains 

 and during exposure in the ordinary receivers of air-pumps. 

 Among the results given by him, we note that, in addition 

 to the generally recognized fact that the aneroids are subject 

 to sudden changes when at all roughly handled, each ane- 

 roid has a system of corrections peculiar to itself, and the 

 further fact that sudden jumps peculiar to an aneroid are 

 produced at corresponding or symmetrical points, according 

 as the pressure is diminished or increased. 



In a second paper upon the correlated subject of baromet- 

 ric hypsometry, he calls attention to the important works of 

 St. Robert and Ruhlmann, and shows that the formula de- 

 duced by the former investigator leads to quite as reliable 

 results as that of the latter. In an appendix he gives a con- 

 venient table for calculating altitudes, for the use of Italian 

 meteorologists, based upon the formula of St. Robert. 



NEW HYPSOMETRIC TABLES. 



The tables constructed by Biot, in 1811, for the computa- 

 tion of altitudes by means of barometric observations, were 

 as convenient as could be desired for this purpose, but have 

 recently been published in a much greater fullness by Kiefer, 

 of Tiflis, who has also given them a still more convenient 

 form. He states that he separates the original Biot's formu- 

 la into three portions, depending respectively on, first, the 

 pressure ; second, the pressure and the temperature ; and. 



* The fullness of the systematic account of the progress of geographical 

 science in the Summary enables us to reduce the amount of space usually 

 devoted to this subject in the body of the " Annual Record." Ed. 



