349 



I. 



TABLES 



FOB 



DETERMINING DIFFERENCES OF LEVEL BY MEANS OF 

 BAROMETRICAL OBSERVATIONS, 



COMPUTED FROM THE COMPLETE FORMULA OF LAPLACE, 

 BY M. T. DELCKOS. 



At Station. 



Construction of the Tables. 



If we take % = difference of level of the two barometers, 

 a = earth's mean radius = 6366200 metres, 

 L = mean latitude between the two stations, 

 and further : 



f h = observed height of the barometer, 

 Lower. \ T = temperature of the barometer, 

 C t = temperature of the air, 

 r h' observed height of the barometer, 

 Upper. \ T' = temperature of the barometer, 



C f ==. temperature of the air, 

 and if we make finally H = h -f- h'. (%^-), 

 we shall have, according to Laplace, the following general and complete equation 



(1 H iooo~) 



( 1 + 0.0028371 cos. 2. L) 



((! + ). Log. (A) +i 0.868589) 



after the proper transformations this equation becomes : 



z = 18336 metres X 



z = Log. 



D 



18336 metres X 



( 1 + 0.0028371 cos. 2. L) 



('g- (T) + 0-868589) . .f 



Log. ( jj-) 

 9 



V 



( 



1 + 



