300 On the Recent and Coming Total Solar Eclipses. [Nov. 23, 



record phenomena observed from ten minutes before totality to actual 

 totality. 



a. Order in which lines appear. 



b. Brightness and length when first visible. 



The spectrum from \ 4800 to \ 5900 should be distributed among at 

 least five observers. 



Repeat observations after totality on point of reappearance. 



(2.) 6-inch photographic lens of four feet focus, perfect clock, same 

 dispersion as above. 



Clamp point of disappearance of sun on centre of tangential slit and 

 record phenomena observed from ten minutes before totality to actual 

 totality. 



a. Order in which lines appear. 



b. Brightness and length when first visible. 



Repeat observations after totality on point of reappearance. Same 

 part of spectrum, same distribution as in (1). 

 (3.) 6-inch photographic lens as in (2). 



Photographic phenomena before and after totality on slowly 

 ascending or descending or rotating plate, taking care to expose only 

 narrow strip of plate. 



(4.) Ditto. Spectroscope of small dispersion, long slit. 



Photograph spectrum of corona during totality on both sides of dark 

 moon. 



(5.) Prismatic camera. 6-inch photo, lens as in (2), but with grating. 



Use first order spectrum on one side and second order on the other. 



Commence two minutes before totality. Continue till two minutes 

 after totality on gradually ascending or descending or rotating plate. 



(6.) 6-inch photo, lens as in (2), mounted on alt-azimuth. Fine slit. 

 One prism of 60°. To observe spectrum of corona. 



(7.) Photographs of corona of short, medium, and very long exposure 

 to determine form and true solar limit of apparent corona due to the 

 illumination of our air, using for the latter purpose the photographic 

 intensity of the image of the moon. 



I am aware that because Solar Physics is a new subject, and one 

 so entirely in the domain of pure science, the above scheme may 

 appear ridiculous to many, for if carried out in its completeness its cost 

 would perhaps amount to the sixtieth part of the sum expended on 

 the Transit of Yenus in 1874. I have, however, felt myself bound to 

 put it forward as an ideal scheme and one which, if several civilised 

 Governments do each a little, concerted action may help us in part to 

 realise. I am informed that the French and Italian Governments are 

 already making preparations for observations, and my desire is that 

 we may be represented on an occasion which, having regard to the 

 duty which is incumbent upon us to secure observations for the use 

 of those who come after us, is one of high importance. 



