184 



SCIENCE. 



[N. S. Vol. XII. No. 292. 



vations showed that a strip of territory in 

 western Georgia and in eastern Alabama, 

 had the best chance of securing observa- 

 tions of the eclipse. But in fact I think we 

 had the poorest weather. A minute after 

 the eclipse was over the sun was thickly 

 clouded over, a large mass of clouds com- 

 ing up from the west. In connection with 

 this I will say that a member of our party 

 made it a part of his business to observe 

 the corona, and he found that he could 

 visually observe the corona 70 seconds after 

 the eclipse was over. We thought it was 

 not worth while to take photographs at 

 that time, but we could probably have fol- 

 lowed the corona longer except for the 

 clouds which came up and covered the sky 

 at that time. With regard to the green 

 ring in 1898, which was shown very much 

 broken up, indicating great coronal activity 

 there, in this eclipse we had the green ma- 

 terial piled up in large masses. 



A Member. I was watching the region 

 of F, to learn how to keep the image in the 

 slit. It was not a gradual nor a sudden 

 change, but a flickering one ; and it went 

 out a number of seconds after the totality in 

 exactly the same manner that it came in, 

 so far as its brightness was concerned. I 

 am sure that if the best arrangements were 

 made to economize the light, a grating of 

 21^ inches focal length could be successfully 

 used. The light from that part of the sun 

 which was upon the slit was not more than 

 l/200thpart of that thrown by the coelostat 

 upon the ruled portion of the grating. If 

 we could in some way economize the slit 

 we might get good results from it. 



Mr. Jewell. Probably the flickering 

 spoken of was due to a slight tremulous- 

 ness of the atmosphere. An interesting 

 thing to observe was the carbon bands, 

 which were exceedingly bright at a dis- 

 tance of 100 or 200 miles above the sun's 

 surface, and which extended out about 400 

 miles. 



OBSERVATIONS OF EKOS AT THE COMING 

 OPPOSITION. 



Simon liewcomb. Some one has divided 

 astronomers into two classes, those who 

 talk about things to be done, and those 

 who go to work and do them. In the 

 present case I am afraid we shall have to 

 enroll ourselves in the first class, because 

 it is not easy to do anything in this matter, 

 the situation in this country not being favor- 

 able to the determination which we have 

 in view. You are doubtless all aware of 

 the great interest attaching to this remark- 

 able asteroid. It may be said to supply us 

 with what we have long been wanting, an 

 object admitting of exact observation, which 

 at proper intervals will come so near the 

 earth that the solar parallax can be deter- 

 mined with greater precision than by any 

 other method. It would hardly be possible 

 to get one more exactly to fill the bill. The 

 minimum distance of Eros from the earth 

 is 0.15 of the distance of the earth from the 

 sun. It follows, therefore, that at certain 

 times it will be about as near to us as ob- 

 servations can advantageously be made. 

 Were it to come very much nearer the ad- 

 ditional advantage would be slight, for the 

 reason that the elements of its orbit could 

 hardly be known with sufficient accuracy 

 to give us greater advantage; 0.15 is all 

 that we can ask for, since that distance 

 will diminish the eifect of errors of observa- 

 tion by six or seven times. We have made 

 very little progress in this direction for fifty 

 years, and may now hope for something 

 more. Yet in Eros, the Fates or whoever 

 rules our destiny, have supplied us with 

 something very tantalizing. It turns out 

 that the nearest approach of Eros to the 

 earth occurs only on rare occasions. A 

 nearest approach occurred in 1894, and an- 

 other approach as near as that will not 

 occur until after the middle of the coming 

 century. But an approach as near as can 

 occur in the next twenty years will take 



