BoEDDicKEE — Oil Lutiar Radiant Heat. 509 



The point of intersection after totality in 1884 fell at 23'' 28 '5™ (or 62 minutes 

 after the middle of the eclipse) with 1-8 % of heat; in 1888 it fell near 8'^ 18-5'°, 

 with 0'6 %• The data of 1888 are constructed hypothetical ones; those of 1884 

 were actually observed. 



5. After the point of intersection the heat-curve (of 1888) keeps almost 

 parallel to the axis of the abscissae for about six minutes ; then it begins to rise 

 again, at first slowly, then with increasing rapidity, keeping all the time at a 

 considerably greater distance from the light-curve than before totality. At the 

 moment of the last contact with the shadow, for instance, this distance amounts to 

 17^ % against 6|- °/ o at the first contact. The same rapid rise was observed in 

 1884. But the curve of 1884 continued practically parallel to the light-cui've till 

 about 15 minutes after the last contact with the shadow, whereas the curve of 

 1888 assumes a peculiar S-shaped bend with the greatest elongation from the 

 light-curve shortly after the last contact with the shadow. I am inclined to 

 consider this bend as the result of some (most probably atmospheric) disturbance, 

 and to believe the more parallel course in 1884 the more plausible one. This 

 would mean that the above-mentioned difference between heat and light-curve 

 ought to be reduced from 17|-7o to about 15 °/^ against 9^ % at the corresponding 

 moment in 1884. 



I need hardly add that such an atmospheric disturbance need not necessarily 

 have occurred at the place of observation, but may have taken place in those 

 regions of our atmosphere which were transversed by the solar rays before they 

 reached the Moon. 



6. About 16 minutes after the last contact with the shadow in 1884, and about 

 17 minutes after the corresponding contact in 1888 the increase of heat begins to 

 become gradually less and less, and in 1888 all but ceases about 7 minutes before 

 the last contact with the penumbra when the total amounts to 80 '6 7o- Up to P 30" 

 after this last contact this quantity increases only to 81 % of Full Moon heat. 

 In 1884 the Moon's heat measured 38" after the last contact with the penumbra was 

 86'8 % of the Full Moon value, so that, generally speaking, a remarkable agreement 

 between the observations has been established. In detail, however, there exists a 

 considerable difference. For whereas in 1888 the heat-curve — as indicated before 

 — remains practically parallel to the light-curve from 7 minutes before the last 

 contact with the penumbra, it continued to rise slowly but unmistakably in 1884 

 till about 14 minutes after the end of the eclipse, and only then showed some 

 approach to parallelism to the light-curve. It would be difficult to say which of 

 the two courses is the more probable one. A glance at Plate LIV. leads, however, 

 to the following consideration in favour of the course of 1884. From this plate it 

 is obvious that at about 8'' 10" some (probably atmospheric) disturbance set in, 



