TOTAL ECLIPSE OE THE SUN, APRIL 16, 1893. 
553 
Illustrations. 
( 1 .) Figures inserted in the text. 
PAGE. 
1. Prismatic Camera employed in Africa. 559 
2. Details of prism mounting. 560 
3. Stowing the position of sun’s axis and equator, April 16th, 1893 . 562 
4. Dark Slide used in Airica. 562 
5. Prismatic Camera employed in Brazil. 569 
6. Dark Slide used in Brazil. 571 
7. Appearances of bright arcs in the spectrum of the cusp. 577 
8. Comparison of 1474 K-ring with the lower corona. 579 
9. Prominences photographed in K-ligbt. 581 
10. Composite ring of chromosphere and prominences in K-light, April 16th, 1893 . 582 
11. Possible appearances of bright arcs at cusp in photographs taken out of totality . 587 
12. Illustrating the comparative lengths of arcs and lines photographed with pris¬ 
matic camera and slit-spectroscope respective’y at beginning and end of 
totality. 589 
13. Illustrating different depths of chromospheres photographed with one exposure . 590 
14. Appearance of continuous spectrum photographed on an isochromatic plate with 
a ring slit. 590 
15. General explanation of photographs taken out of totality. 591 
16. Comparison of the spectrum of the base of the chromosphere with Fraunhofer 
lines. 606 
(2.) Plates. 
11. Airican photographs, Nos. 7 and 21. 
12. African photograph, No. 18. Brazilian photographs, Nos. 2 and 12. 
13. African photographs, Nos. 22, 23, 24, and 25. 
14. Enlarged spectra of prominences and base of chromosphere, and comparison of the 
latter with the spectrum of Arcturus. 
PART I.—THE OBSERVATIONS. 
I. Introduction. 
The results obtained by Professor Respighi and myself during the eclipse of 1871 
in India, in which part of the attack consisted in the employment of slitless spectro¬ 
scopes—a method of work at which we had arrived independently—indicated the 
extreme value of such observations. 
For my own observations in 1871 I had arranged a train of five prisms without 
either collimator or observing telescope. “ I saw four rings with projections defining 
the prominences. In brightness, C came first, then F, then G, and last of all 1474k. 
Further, the rings were nearly all the same thickness, certainly not more than 
2' high, and they were all enveloped in a band of continuous spectrum. 
* “ Nature,” vol. 5, p. 218, 1872. 
4 B 
MDCCCXCVT. —A. 
