BY H. F. WALLMANN. 



Others which have altogether passed into malachite. Not only 

 are their peculiar colour and transparency lost, but the specific 

 form of the crystals themselves is affected. Malachite appears in 

 the form of azurite, one carbonate has the crystalline aspect of 

 the other. Why ? Simply as the result of a loss of carbon and a 

 compensation of that loss by water and copper oxide ; a process 

 which goes on in the mass from without inwards. 



In contrast with this latter action we may lastly notice two 

 other and different effects of pseudomorphic causation. 



In the first a covering of malachite is formed over crystals of 

 cuprite. The encasing may be partial or entire. The cuprite form 

 of crystal is retained and we have malachite in octahedrons, 

 cubes, twins after octahedrons, and other forms of the system — a 

 change of form, which is accompanied by an important loss of 

 specific gravity. The pseudomorphs of this kind from Cloncurry 

 are equal in size and beauty to those of Ohessy, near Lyons, in 

 France. 



The second of this class of pseudomorph indicates the same 

 process. Malachite covers and fills the crystal form of carbonate 

 of iron, siderite. 



These last two kinds of pseudomorph are indeed well known, 

 but a notice of them appeared necessary to render our review of 

 the various modes of pseudomorphism complete. 



I have to thank the Trustees of the museum for permission 

 to exhibit the specimens on which these observations are founded. 



ON THE BOWEN CYCLONE OF 30 JANUARY, 1884. 



By Mr. JAS. THORPE. 



(Plate X.) 



On 30th January last a storm of an unusually severe character 

 passed over the portion of N. E, Australia near 20° S. and 

 148° E. 



This storm was of a well-marked cyclonic character, and as 

 it possessed some features peculiar to itself I have thought it 

 worth while collecting what information was possible from various 

 sources with reference thereto. The results I lay before you, 

 together with chart showing, by the recorded variations of the 



