NO. 8.] PENDULUM OBSERVATIONS. 9 



watch is given for 24 hrs., the correction, u, is 58 6 units in the 7th decimal 

 place for every second. The correction for the amplitude, a, is 



. 9a 



a ST ,2 O, 



where a is the observed amplitude, and I the distance in millimetres between 

 the coincidence apparatus and the pendulum mirror, while S is the period of 

 the pendulum. Each division on the scale is equal to 3 mm. 



For the thermometers before the journey, we have, according to the 

 above, 



Thermometer 20 t C. = 1-863 (reading 3'41) (in 1892) 



23 t C. = 1-988 (reading 2-66) 



24 t" C. = 1-903 (reading 2-16); 



during and after the expedition, 



Thermometer 20 t C. = 1-863 (reading - 3'41) 0.09 (in 1893 and 



subsequently) 



23 t C. = 1-988 (reading - 2-66) 0.25 



24 r C. = 1-903 (reading 2-16) 0.375. 



