59° 



NA TURE 



{Oct. 1 6, 1884 



latter by the re-winding of the driving-clock of the tele- 

 scope. Thus I took altogether 211 readings of the gal- 

 vanometer, which were taken together in groups of ten 

 for the formation of reliable mean values. It is these 

 means — without the application of the still necessary re- 

 ductions — which form the ordinates of the preliminary 

 curve inclosed, the abscissa; of which are the times before 

 the beginning and after the end of the total phase. It 

 will be seen that no observations were made during the 

 total phase, as I could not make certain that the moon's 

 image was actually on the condensing mirrors ; besides 

 the readings of the galvanometer on near approach to 

 the total phase became so unsteady and irregular that it 

 was plain that the effect, if any, fell below the sensitive- 



Curve showing the change of the lunar radiant heat as measured by thermo- 



I '■ .I'M .' 1!'. -I'll' '.lining til'.' ti i!.ll < < I'}' •' 1 il ill'.' II mi HI I'll < >i 1"1"T .: 



1884, at Birr Castle Observatory, by Otto Boeddicker. 



ness of the instrument and the unavoidable errors of 

 observation. This is much to be regretted, as the few 

 observations obtained before the total phase began show 

 plainly that the minimum of the radiated heat takes 

 place later than that of the moon's light. Indeed, so 

 slowly did the readings of the galvanometer increase 

 again that about twenty minutes after the total phase was 

 over the almost entire absence of any effect led me to 

 think that the small condensing mirrors must be covered 

 with dew, an apprehension which was happily not veri- 

 fied. I should add that the galvanometer readings here 

 given are not comparable with those published in 1873. 

 Otto Boeddicker 

 The Earl of Rosse's Observatory, Birr Castle, 

 Parsonstown 



THIS eclipse was seen from here (height above sea 

 530 feet) to great advantage in a cloudless sky, with the 

 stars very brilliant and the air calm. 



For some minutes before the actual contact a faint 

 smoky look was visible, and this had the effect of flatten- 

 ing the edge of the moon on the side towards which the 



shadow was approaching. At 8h. 16m. there was a slight 

 but very perceptible shadow, about a fourth of the moon's 

 diameter in advance of the dark shadow, and in four 

 minutes later the eclipse just entered the moon. At 

 8h. 44m. the margin of the dark shadow, which had had all 

 along an edge of a woolly and irregular appearance, had 

 now decided streaks in advance of it. The edge of the 

 moon on the opposite side from the base to within 30° of 

 the apex was marked by a rim of intense bright blue. 

 Ten minutes later the blue margin was less brilliant and 

 narrower, and the woolly appearance before mentioned 

 was more decided, but less streaky. At Sh. 58m. the blue 

 had contracted in length both at the base and apex, and 

 gradually assumed a greenish shade. The cusps of the 

 moon were elongated and more drop-like than continuous. 

 At gh. 1 8m. the shadow had almost covered the moon, 

 which showed a faint glow beneath, though the circular 

 appearance was not visible to the na'ced eye. A minute 

 later, as the last point of light disappeared, a dense black- 

 ness of irregular form appeared on the opposite portion 

 of the moon, extending over nearly a third of the surface. 

 At 9I1. 39m. the moon was scarcely perceptible to the 

 naked eye. Through the telescope a faint luminosity at 

 the apex could be discerned. At 9I1. 47m. to the naked 

 eye the moon seemed like a blurred star, very indistinct 

 and considerably reduced in apparent size, and of no 

 definite form. At ioh. 2m. the faint luminosity at the 

 apex had almost gone, and the outline of the moon was 

 more apparent through the telescope. The blurred, star- 

 like appearance to the naked eye was still unchanged. 

 At ioh. 9m. there was a thin luminosity on both horizon- 

 tal sides of the moon. The apex of the moon was very in- 

 distinct. At ioh. 20m. a broader belt of light appeared 

 on the northern side, but that on the opposite side was 

 indistinct. There was still the same indistinctness to the 

 naked eye, though every now and then a faint crescent- 

 like appearance could be seen. At ioh. 38m. a somewhat 

 broader crescent. At ioh. 43m. a bright light like that of 

 the moon was visible to the naked eye at the apex, and 

 four minutes later the moon reappeared. At ioh. 57m. 

 the tip of a mountain was lit up near the moon's apex. 

 At 1 1 p.m. the upper cusp extended further than the lower 

 one. At 1 ih. 15m. a slight haze formed a burr about the 

 moon, which was somewhat kidney-shaped. At nh. 22m. 

 the burr still visible, but much rounder in form. The 

 eclipse ended at nh. 45m. 



Having previously observed a number of lunar eclipses, 

 I was specially struck with that of to-night ; the density 

 and blackness of the shadow was far greater than any 

 previous one that I had seen, especially throughout the 

 period of totality. In all previous eclipses I have been 

 able to trace the outline ; in the present case this was 

 quite impossible. Usually the outline is more or less 

 plainly been, and not unfrequently there is a strong red- 

 dish light. The last total eclipse of the moon was seen 

 from this place, and it had a copper-coloured appearance, 

 and there was no difficulty in tracing the outline. In the 

 present eclipse the moon's outline was invisible for some 

 time to the unaided eye, and the apparent size so much 

 diminished that it had more the appearance of a large star 

 whose light was just able to pierce through a dense haze. 

 Some of the valleys of the moon were left for a time in 

 great darkness after the light had travelled beyond them. 

 I may mention that all the above appearances were also 

 seen by Major A. E. L. Lowe and Mr. H. L. 1>. Lowe, 

 who were using other telescopes. E. J. LOWE 



Shirenewton Hall, near Chepstow, October 4 



1 r is to be hoped that the unusual phenomena attend- 

 ing the late eclipse of the moon may lead to a discussion 

 which will throw some light upon the great differences 

 observed on different occasions in the visibility of the 

 eclipsed moon — differences which have not hitherto, so 

 far as I know, been adequately explained. 



