nearly bank-high, while the living cataract travelled onward much slower than I had expected to see it; so slowly, indeed, that more than an hour after its first arrival the sweet music of the head of the flood was distinctly audible, as the murmur of waters and diapason crash of logs travelled slowly through the tortuous windings.... The next morning the river had risen to within six feet of the top of its banks, and poured its turbid waters along in fulness and strength, but no longer with noise. All night that body of water had been in motion downwards, and seemed to me enough to deluge the whole country.” So little has as yet been ascertained respecting the climatology of western, north-western and northern Australia, that it is not known whether they also are subject to these tremendous visitations; but as we have reason to believe that the intertropical parts of the country are favoured with a more constant supply of rain as well as a lower degree of temperature, it is most probable that they do not there occur. Independently of the vast accession of birds attracted by the great supply of food, as mentioned above, there are many species which make regular migrations, visiting the southern parts of the continent and Van Diemen’s Land during the months of summer, for the purpose of breeding and rearing their progeny, and which retire again northwards on the approach of winter, following in fact the same law which governs the migrations of the species inhabiting similar latitudes of the Old World. There are also periods when some species of birds appear to entirely forsake the part of the country in which they have been accustomed to dwell, and to betake themselves to some distant locality, where they remain for five or ten years, or even for a longer period, and whence they as suddenly disappear as they had arrived. Some remarkable instances of this kind came under my own observation. The beautiful little warbling Grass Parrakeet (_Melopsittacus undulatus_), which, prior to 1838, was so rare in the southern parts of Australia that only a single example had been sent to Europe, arrived in that year in such countless multitudes on the Liverpool plains, that I could have procured any number of specimens, and more than once their delicate bodies formed an excellent article of food for myself and party. The _Nymphicus Novæ-Hollandiæ_ forms another case in point, and the Harlequin Bronze-winged Pigeon (_Peristera histrionica_) a third; this latter bird occurred in such numbers on the plains near the Namoi in 1839, that eight fell to a single discharge of my gun; both the settlers and natives assured me that they had suddenly arrived, and that they had never before been seen in that part of the country. The aborigines who were with me, and of whom I must speak in the highest praise, for the readiness with which they rendered me their assistance, affirmed, upon learning the nature of my pursuits, that they had come to meet me. The