( 245 ) 



A 4"^^^ inequality in the rates wa.s due to the difference between 

 the personal e(|uations of the ol)servers. From direct detei-niinations 

 we have obtained the following cliilerences in the clock corrections : 



B— P 

 1 April 1901 — ()'201 



18 iAIarchl903 —0.275 



15 March 1904 —0.224 



For the time being I have adopted for this difference during the 

 I)eriod Jan. 14, 1903— Jan. 14, 1904: —0^250 and have rechu-ed 

 the clock corrections determined by P. to B.'s system. Besides the 

 corrections for atmospheric pressure, temperature and difference in 

 temperatnre I introduced a correction for the assumed personal equa- 

 tion ; these 4 unknown cpiantities are introduced into the equations 

 and will be derived from the observations. 1 represented them l)y 

 ,r, y, z and u and chose the following units so that these quantities 

 should have about the same values : for atmosplieric pressure {B) 

 tiie unit = V4 "^"*- mercury of 0^ C, for temperature {d) the unit 

 = 7io tlegree Celsius, for difference in tem|)erature ( V) the unit 

 = Yioo degree Celsius, for clock rates per day the unit =r Yiooo 

 second of time; x, y and z represent the influence of each of the 

 three units on the daily rate, expressed in thousandth parts of a 

 second of time, while u is the 10^'' part of the correction for the 

 assumed difference in the personal equations of the obser\'ers during 

 the same unit of time, viz. B — 7-* = — 250 — 10 u. 



§ 6. The observed clock corrections were reduced beforehand to 

 midnight of the data of observation. This was done with clock rates 

 according to a [)reliniijiary formula with due regard to atmospheric 

 pressure, temperature and temperature difference in the period from 

 the instant for which the clock correction was determined to mid- 

 night. This formula is derived from observations durijig the tirst iiaif 

 of 1903, it has been regularly tested by each new determination of 

 the clock error, and has proved very satisfactory fur the [)urpose 

 set here. 



Constans = daily rate— 0.0157 (bar. — 7(50) -f- 0.032 (temp. — 10^ C.) 



s 



— 0.31 (tenq). difference). 



development of Ij. Wanacii of Potsdam on the inlluenco of llie lempenUnro-gradienl 

 on clocks (A. N. Nrs. 3!)ü7 — 68) I think it worlli mentioning tliat in tins way I 

 found that per 1 (;entigiade dillei-once in lompoiaturo l)etween llio tliermomelcrs, 

 lliere was a variation in rale of about U^8(), twice the amoiml d<'iived from the 

 before mentioned observations. 



