360 THE EOYAL SOCIETY OF VICTORIA. 



as nearly the truth, and makes the difference of longitude 25m. 33.78s. Assuming' 

 the longitude of Melbourne to be correct, that of Adelaide would be 9h. 14m. 

 21.02s. 



Before leaving the subject of our astronomical labors I would add a word con- 

 ceniing the total eclipse of the sun, which will take place on the 17th of August, 

 this year. 



The eclipse will be a most remarkable one, and unrivalled by any recorded in 

 the annals of mankind in its magnitude and duration. At its commencement 

 the moon will bo unusually near the earth, and at the same time reaches the 

 ascendingnode of her orbit. The sun also reaches nearly the zenith of those places 

 where the eclipse takes place at noon ; the augmentation of the moon's apparent 

 diameter, due to her altitude, is a maximum ; a combination of circumstances 

 resulting in the apparent diameter of the moon exceeding that of the sun by an 

 miusual amount, and in the time during which the sun Avill remain eclipsed, being 

 almost unprecedented. 



The greatest length of totality will occur in longitude 102° 38' E. and 10° 28' 

 N. in the Gulf of Siam, where it lasts 6m. 50s. The path of totality, which 

 commences at sunrise in Abyssinia, passes over the Straits of Babel Mandeb, 

 Aden, Arabia, through India between Goa and Rajaiioor, across the Gulf of 

 Siam, where the greatest phase occurs, then through Borneo, the whole of the 

 south of New Guinea, ending at sunset about the New Hebrides. 



So unusual an eclipse as this is sufficient to put astronomers on the qui vive, 

 for such an one has probably never been seen by man, and none of such magni- 

 tude is likely ever to l>e witnessed by any now living. But there are, however, 

 higher objects than this in view, and great preparations are being made to carry 

 out investigations concerning the sun's atmosphere, which can only be attempted 

 during total eclipses, and for which this f)ne offers so long a period of totality. 

 It has long been supposed that an atmosphere surrounds the sun's exterior to the 

 photosphere. Those remarkable red clouds or prominences and the corona or 

 glory with its projections, generally seen in total eclipses, and especially in that 

 of 1860, all point to this. These luminous clouds were found by Mr. Do la Rue 

 to have great photographic power, and ]\[r. Braylc}' concludes therefrom that 

 they probably consist of" incandescent globules of metal in a licjuid state, or per- 

 haps of solid particles of the metals discovered in the sun by Kirchoff. The 

 optical means of analyzing the light from various sources have been so much 

 improved since the last total eclipse Avitnessed by astronomers in 1860, and our 

 increased knowledge of the physical conditions of the sun, as well as of many other 

 of the heavenly bodies, induces the scientific w'orld to confidently hope that the 

 telescope, spectroscope, and heliograph will reap rich harvests in the hands of 

 the many experienced ol)servers who will be engaged in the path of totality. 



The botanical department, so efficiently conducted liy your fellow-member, 

 Dr. F. Mueller, has not been idle. The " Fragmenta Phytographa Australis," I 

 am informed, will have reached the completion of the sixth volume next month. 

 Dr. Bentham's new work on the Australian flora (to which Dr. Mueller contributes 

 largely) is progressing rapidly ; the fourth volume containing the Candollian 

 division — corollifloraj — is nearly complete ; the fifth volume, which it is expected 

 will be issued next year, will contain the monochlamydese ; and it is intended to 

 follow it up by a sixth volume, containing the monocotyledons and ferns. A 

 supplementary volume will afterwards be probably issued, to comprise the newer 

 discoveries among cotyledonous plants, for which the '' Fragmenta " will aftbrd 

 the principal records. This book will be the most complete descriptive work on 

 the vegetation of Australia, and with which, in its completeness, no similar work 

 on European vegetation can compare. You will be glad to leara that the cinchona 

 (Peruvian l)ark) plants are prospering. Dr. Mueller informs me they have been 

 exposed to extremes of temperature varj-ing from 30° Falir. last winter, to 100° 

 Fahr. during this summer, in an artificial fern gulley in the gardens without injury ; 



