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SCIENCE. 



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



miles from the solar surface. One word 

 with reference to future work : I think it is 

 very desirable to use a concave grating in 

 the ordinary way, but instead of using a 

 dense lens of quartz, to use a very large 

 concave reflector of a focal length of 100 to 

 150 inches, which would give an image of 

 the sun an inch and a half in diameter ; 

 and then we could use a wide open slit so as 

 to be certain to get the limb of the sun in- 

 side of it. At Pinehurst we had to cut 

 down the slit in consequence of the curva- 

 ture, and had an image of the sun only a 

 third of an inch in diameter to work with. 

 In future work much the best plan will be 

 to use two concave mirrors, one of a short 

 focus for the dense lines, and the other of a 

 considerable focal length, the slit being 

 placed between them. In this way we can 

 let the light come through the narrow slit, 

 and then the larger and long focus mirror 

 will act as a condenser, and there will be 

 no disturbance whatever in the focus. A 

 telescope of high power should be used, and 

 focused very carefully ; and the light re- 

 flected from the second mirror would give 

 us parallel light ; and if the adjustments 

 were well made the image would be very 

 sharp. By that method we ought to be 

 able to obtain very satisfactory results. 



"Winslow Upton. I will report briefly 

 the work we did near Norfolk by very 

 ordinary astronomical and photographic 

 processes. We had a four-inch telescope 

 for visual work ; and we had an equatorial 

 stand upon which a camera was carried by 

 clockwork. The camera contained two very 

 long focus lenses. We also had four ordi- 

 nary cameras, which we used for the purpose 

 of obtaining the extension of the corona. 

 We found that the duration of the eclipse 

 was shorter than calculated. By the Eng- 

 lish and the American Ephemeris it was 101 

 seconds, while we made it 99 seconds. In 

 the visual observations we used a magnify- 

 ing power of 50 or 60. At the time I did 



not notice the hooded arrangement of the 

 corona, this gigantic hood overlapping the 

 strata, shown in the photographs of the 

 eclipse of 1878. In our observations to de- 

 termine the place of the moon, and in the 

 search for an intra-Mercurial planet, we 

 carried out the instructions of Professor 

 Pickering, which were to expose for 60 

 seconds. Our cameras covered a range 

 about 25° along the sun's equator, and with 

 8 or 10 gigantic plates we covered that re- 

 gion ; but we got nothing except one or two 

 bright objects, possibly only the planet Mer- 

 cury, and there seemed to be star trails in- 

 stead of images, perhaps from a fourth 

 magnitude star. I think the exposure 

 might have been longer ; for I feel confi- 

 dent that we could have exposed 80 or 90 

 seconds without fogging the plate. For the 

 spectroscopic work we used triple- coated 

 plates, especially made for us by the Seed 

 Co., and also orthochromatic plates. With 

 regard to the development of the plates we 

 decided to vary from the instructions of the 

 Committee. The instructions were that we 

 should use an exceedingly weak developer 

 and develop a long time. Professor Picker- 

 ing on the other hand recommended a strong 

 developer, and a great deal of bromide. As 

 we had duplicate plates we decided to try 

 both plans, and I think on the whole that 

 we obtained better lines with the strong de- 

 veloper and the bromide restrainer. I have 

 here some lantern slides which I will show. 

 Ormond Stone. The University of Vir- 

 ginia took part in the eclipse observations 

 at Waynesborough, N. C. We used a 40- 

 foot camera. I desire here to express my 

 gratitude to Professor Campbell for the ad- 

 vice he gave us at the beginning, and for 

 his kindness in assisting in the preparations, 

 and also in developing our plates for us. 

 Our preparations were begun very early 

 and we went to the camp about a month 

 before the eclipse took place. At the time 

 of the eclipse the sky was perfectly clear, 



