SOME NOTES ON JFPITEE DURING HIS OPPOSITION OP 1876. 93 



opinion as to the tawny yellow of the equatorial zone, as seen in 

 that description of telescope. 



Now I must confess I am at present totally at a loss for a 

 theory to account for these contradictions. The refractor showing, 

 as the best object-glasses do, a fringe of uncorrected purple or 

 violet light round a bright object such as Jupiter, ought according 

 to theory, to give the planet if anything a yellow tint, that being 

 the complementary colour ; but this is exactly what it does not 

 do. The refractor, on the contrary, ought to give a reddish cast, 

 as the reflection from silver is slightly tinged with that hue ; but 

 this is just the colour that it refuses to show. There is some 

 unexplained mystery here, which I cannot now stay to inquire 

 into, but content myself with putting just the bare facts before you. 



The great equatorial belt of Jupiter appears at times to be the 

 seat of sudden and violent disturbances, taking place on a scale 

 of which we can scarcely form any conception. I have seen the 

 whole appearance of this belt alter during the interval of from one 

 night to another, so that though the same portion of the disk was 

 presented to the eye, not a single feature in this part of the planet 

 could be recognized in the drawing of the previous night. One 

 notable example of this occurred on the 24th May. The equa- 

 torial belt had presented a particularly quiescent appearance for 

 some time before, occupying not more than a third or a fourth of 

 Jupiter's diameter. On the evening of the 24th of that month 

 I noticed that it had suddenly spread over fully one-half of the 

 disk, and seemed to be the seat of the wildest commotion, being 

 torn and twisted in the strangest manner. Curious to say, this 

 only applied to one side of the planet, for the opposite side pre- 

 served the calm appearance before referred to, the equatorial zone 

 being exceedingly narrow. This outbreak lasted for some two 

 weeks, and then gradually appeared to calm down. On the 23rd 

 June there was another similar outbreak, accompanied as before 

 by another extension of the equatorial belt, and also — and this is 

 why I particularly mention it in this part of my notes — by an 

 almost total loss of the yellow colour so remarkably predominant 

 before in this part of the planet. This loss of colour seems to 

 arise from the spreading over the yellow belt of the dark-gray or 

 chocolate-coloured bands with which it is usually streaked ; during 

 these out-breaks they appear to extend as it were laterally, and 

 to colour almost completely the yellow, which is only then seen 

 between them in thin streaks. A strange feature noticed by me 

 on the 4th July was that one of these dusky bands was bordered 

 by a narrow edge of crimson lake ; it could not have been more 

 than a second or two of arc in diameter, but was most vivid ; and 

 it gave me almost the impression as if I were looking at a scarlet 

 or crimson flame. > 



The polar portions of Jupiter, to which I will next direct your 



