94 SOME NOTES ON JTJPITER DTJEING HIS OPPOSITION OP 1876. 



attention, do not present the same ever-varyiDg character of the 

 equatorial belt ; the causes which produce such tremendous dis- 

 turbances at the equator do not appear to aftect in anything like 

 the same degree the northern and southern latitudes. You will 

 observe in the large diagram, that I have coloured the north pole 

 a decidedly brownish green, and this is the almost uniform tint 

 that it has presented to me. On evenings of bad definition the 

 green is scarcely visible : but when the air is sufficiently steady 

 it is most conspicuous, and is a very beautiful feature : it requires 

 a certain amount of magnifyiug power and considerable aperture 

 to bring it out well ; it is scarcely apparent with anything under 

 100, and a power of not less than 200 is by far the best, if the air 

 will bear it. The reflector seems to possess a decided ad^^antage 

 over the refractor in showing the green tint ; in the large Obser- 

 vatory achromatic it appears to me more of a smoky brown. The 

 only record I can find of a green tint being observed at the poles 

 is one in the " Transactions of the Royal Astronomical Society," 

 by Miss Hirst, a lady residing in Auckland, who observed Jupiter 

 during his opposition in 1875 with an 8|^-inch reflector. She 

 says — " On February 20th I noticed a small oval patch of a 

 decided sea-green at the south pole, which on the following 

 morning was more elongated and a shade darker in the centre. 

 It remained thus for three days, and has not since been seen." 

 The south pole has on all occasions been tinted with a warm gray. 

 The most remarkable feature on this portion of the planet has 

 been the persistent appearance of a cloudy mottling, which I have 

 attempted to represent in the diagram. This was first noticed on 

 the 3rd May, and it has continued to appear at intervals up to the 

 present date. 



Of the markings generally on the planet there are one or two 

 which I will mention as being particularly characteristic and per- 

 sistent. The strangest-looking of them is the one Mr. E-ussell 

 and myself called the " Fish," on account of its presenting some- 

 thing of that form. It first made its appearance during the great 

 outbreak about the 24th May ; and it existed, though somewhat 

 altered in shape, until the 4th July ; there were always one or 

 two black spots on the southern edge of it. The next peculiar 

 marking was one I called the " Tuning-fork." I have represented 

 it here on the diagram. On the north rim of the equatorial belt 

 there appeared from the beginning of May to the middle of June 

 a succession of remarkable breaks, the dark band on the following 

 side being as it were cut short ofi", and on the preceding side it is 

 thrown suddenly up, and extends right across the disk in a thin 

 streak. 



We have been accustomed to talk of the belts and clouds of 

 Jupiter as if they were in their nature somewhat analogous to the 

 clouds of watery vapour in our own atmosphere, or as perhaps 



