448 Chronicles of Science. [July, 



must be of equal density throughout. Treating the disc by optical 

 methods, Mr. Cooke expects to fulfil these conditions. 



The next paper brought forward was a long mathematical 

 discussion on the " Lunar Theory," by Professor Cayley. This defies 

 condensation. 



Mr. F. Abbott communicated a note on the variable star y\ Argus 

 and the surrounding nebulae. He is satisfied that continued changes 

 are constantly taking place in this nebula, and that it is gradually 

 breaking up into stars. In former notes he described the so-called 

 dark space as resembling in shape a clearly-defined " crooked-billet ;" 

 it now assumes a very different form, and what is singular, Sir J. 

 Herschel describes k Crucis in glowing colours, " like a rich piece of 

 jewellery ;" but he is silent as to the colours of the stars around 

 t) Argus. In former notes the author mentioned many of them as 

 being of a ruddy colour ; but now they are of decided colours — blue, 

 green, and red, the two former predominating. If the telescope is 

 turned from one object to the other, it will be seen that, although Sir 

 J. Herschel has not overdrawn the beauty of % Crucis, the object 

 tj Argus is now much more superb, y standing out sharp and clear, 

 amidst a large field full of richly-coloured gems with only a very 

 small patch of nebulous matter seen under the telescope. In February 

 last, during the period of full moon, the position of y Argus was dis- 

 tinctly seen with the naked eye, by the white light that surrounded 

 it, although the star could not be seen as a point, nor could the 

 position of Nebicula Major, Nebicula Minor, the Via Lactea, or any 

 other nebula be seen at the time. This appears plain proof that the 

 objects composing the nebula around y Argus are now of a larger 

 character, and more refulgent than nebulous matter in general. 



We can make the same remarks with reference to a paper, which 

 was next read, by C. G. Talmage, Esq., " On an Appearance presented 

 by the Spots on the Planet Mars," that we did in respect to the paper 

 by Mr. Joynson on the same planet. 



The concluding papers were devoted to observations on a large 

 comet, which was visible at the commencement of the year in the 

 Southern hemisphere. They are by J. Tebbutt, jun., Esq., Windsor, 

 New South Wales ; E. C. J. Ellery, Esq., Melbourne Observatory ; 

 and F. Abbott, Esq., Hobart Town. 



III. BOTANY AND VEGETABLE PHYSIOLOGY. 



M. Planchon has made some observations on the Flora of Montpellier, 

 from the 15th century up to the present date. The neighbourhood of 

 that city possesses special interest as regards botanical geography. 

 For three centuries celebrated botanists have made excursions in the 

 locality, and have left traces of .their observations in their writings 

 and herbaria. By this means we can observe the introduction and 

 disappearance of certain species, such at least as have well-charac- 



