198 



NA TURE 



[July 2, 1896 



observers in pairs, and they should not compare notes. 

 If telescopes are used, two inches aperture and a 

 power of twenty should be employed for choice. 



Before Totality. 



(I.) Note how long the corona is visible before totality, 

 along the edge of the dark moon opposite the point at 

 which the sun is about to disappear. 



(II.) Sketch any rays visible before totality; give 

 length, colour, and structure as well as position. 



At Commencement of Totality. 



(III.) Sketch general outline and rays (streamers) and 

 rifts (dark intervals between bright rays.) 



(IV.) Note if there be a blaze of light or glare where 

 the sun has just disappeared, and whether the base of the 

 corona is brightest near or away from prominences. 



Middle of Totality. 



(V.) Sketch general outline rays (streamers) and rifts ; 

 note colour and direction of greatest extension. 



Near End of Totality. 



(VI.) -Sketch general outline, and any rays or streamers 

 or rifts ; note colours. 



(VII.) Note if there Ije a blaze of light or glare where 

 the sun is about to reappear. 



After Totality. 



(VIII.) Sketch any rays that may be visible ; give 

 length, colour, and structure, as well as position. 



(Jitestions to he ans^vered in ivriting immediately Totality 

 is over. 



(a) Has there been any change in the appearance of 

 the corona during the eclipse ? If so, specify what change. 



{6) Have especially the dark rays or rifts changed 

 during the eclipse. 



(c) Describe what has been unchanged throughout, and 

 define its structure. 



(d) State the colours you observed outside the red 

 prominences. 



(<?) Were the colours anywhere arranged in layers 

 round the sun ? 



(/) Were the colours anywhere arranged radially ? 



(^) State colours of rays, and of spaces between them. 



(/i) Did the dark rifts extend down to the moon, or 

 did they stop short above the denser layers of the 

 chromosphere ? 



(/) Were the rays brightest near, or far awaj- from the 

 moon? 



(A) What was the comparative brightness of the rays, 

 the bright ring near the sun, and the outer corona ? 



(4) Colours of Land- and Sea-scape. 



Some time before totality there will be a notable 

 change in the colours of sky, cloud, and land and water 

 surfaces. 



Each of these should be noted separately, and the 

 gradual changes, both as totality is approached and 

 after it is over, should be carefully recorded. 



This apparent change of colour has its origin in the 

 coloured chromosphere and prominences ; those witness- 

 ing the eclipse are thus enveloped in coloured — generally 

 red — light, which bathes the landscape. The sky, 

 ordinarily blue, is seen through a red haze, and therefore 

 puts on a purple tint. 



That the sky appears more purple at some eclipses 

 than at others, is owing to the fact that the quantity of 

 red light is not always the same, but varies with the 

 brightness and magnitude of the prominences visible at 

 the time. 



NO. 1392, VOL. 54] 



The following table will give an idea of the colours, 

 both of the corona and landscape, which have been pre- 

 viously recorded. 



(5) The Visibility of Stars during the Eclipse. 



The light radiated by the solar surroundings varies 

 very much from eclipse to eclipse. Hence sometimes 

 lamps are necessary for certain of the operations, while 

 at others they are superfluous. 



The number of stars visible, therefore, varies consider- 

 ably. The sun this year at the time of the eclipse will 

 be near the chief stars in the constellation Leo, which 

 will be to the left of the sun. 



Note, by means of a star map, what is the magnitude 

 of the faintest stars visible, whether first, second, third, or 

 fourth. 



Suggestions for Timing the Progress of the Eclipse. 



In Sicily, in 1S70, the following method of recording 

 the lapse of time during totality was introduced, and was 

 found to prevent all excitement, and made the 80 seconds 

 seem a long time. 



Determine the number of seconds of totality at the 

 station — say 100. 



Then, at the moment of totality, let a person at- 

 tached to each party of observers, carefully observing 

 the face of a chronometer or watch, say, " Vou have now 

 100 seconds." After 5 seconds, "You have still 95 



