1459 
contact and 3348s after third contact; so, on the average, 33?/, 
minutes were required for the moon to cover the second effective 
half of the solar disk. 
Now, at Burgos the moon’s edge took %7°/, minutes to cross the 
whole solar disk; at Maastricht, in 1912, it took 80*/, minutes. If, 
therefore, the ratio of the radius of the moon’s disk to the 
radius of the sun’s disk had been the same in both cases, then the 
time necessary for covering the second effective half of the solar 
2 ()3 
disk would have been, at Maastricht, 33°/, X 74) = very Tea 
4 
35 minutes. 
But at Maastricht the moon’s radius was practically equal to 
the sun’s radius, whereas at Burgos the radii were in the propor- 
tion 152,8:126,8. This difference between the two cases implies 
that the interval of 35 minutes, calculated for Maastricht, is a little 
too great. Indeed, when drawing circles representing the sun and 
the moon in the right proportion and position, and taking the 
distribution of brightness on the disk into consideration, one easily 
concludes that the interval has to be taken about 25 seconds smaller 
say 34'/, minutes. 
Consequently, the results obtained in 1905 required that in 1912, 
at the epochs 0020s and 1'9™20s (i.e. 34'/, minutes before and 
after centrality), the radiation should have shown half its maximum 
4960 
intensity, or = 2480 scale divisions. This is indicated by the 
points 5. The agreement with the actual observations of 1912 is 
indeed very satisfactory. 
During the middle phase of the Burgos eclipse the conditions were, 
on the contrary, so unfavourable, that the central part of the radiation 
curve, there obtained, claims no confidence. 
It was worth while, therefore, to found on our present eclipse-curve a 
renewed application of the method, formerly devised '), of determining 
the rate of decrease of the radiating power from the centre toward 
the limb of the solar disk. 
Discussion of the thermopile results. 
On a homogeneous piece of paper a circle of 40 centimeters in 
diameter, representing the sun, was drawn, and divided in the man- 
ner shown by the adjoined figure’). There are conceniri¢c zones, 
1) Astrophysical Journal 23, 312, 1906. 
2) The figure is not a copy of the original drawing, as this could not be so 
much reduced on account of the delicacy of the lines, 
