214 PETEOLOGT. 



TJLRTcn, G. H. F. A Descriptive Catalogue of 577 Specimens of 

 Hocks in the Industrial and Technological Museum, collected from 

 all parts of Victoria. "With Explanatory Notes on their Character, 

 mode of Occurrence, and Geological Eolations. Eeport of the 

 Trustees of the Public Library, Museums, and National Gallery of 

 Yictoria, for the year 1873-74, pp. 36-66. Melbourne. 



A classified catalogue, with geological notes on the specimens. Tables 

 showing the chemical analysis of many of the specimens are given. 



Ylaandeeen", Dr. C. L. Eetbare aarde van de Humbolts-baai, Nieuw- 

 Guinea. Jaarb. Mijn. JSTed. O.-Ind. Jaarg. 3, Deel 1, p. 179. 



A sample of edible earth from Humboldt's Bay, New Guinea, was 

 soluble in hydrochloric acid, with the exception of about 1*5 per cent. 

 The principal constituents of the earth were soluble silica, magnesia, 

 oxides of iron, and water. , P. W. E. 



YoGELSANO, Heemafn. Die KrystaUiten. [Published after the death 

 of the author by Peedinand Ziekel.] Pp. 173, 16 plates. 8vo. 

 Bonn 1875 (1874). 



Treats of the phenomena observed in the separation of crystaUizable 

 substances from viscid media capable of opposing sufficient resistance 

 to the aggregation of the unit particles at the moment of solidification 

 to prevent the formation of definite crystals. The author first treats of 

 the aggregations of globules, linear and radiated aggregates, observed 

 when sulphur dissolved in bisulphide of carbon is prevented from crystal- 

 lizing by the addition of Canada balsam to the solution, and describes the 

 difi'erent results obtained by microscopic observation, according as the 

 crystallizing power of the sulphur or the resistance of the solvent 

 medium prevails. The information so obtained is applied to the study 

 of the imperfectly-crystallized silicates found in vitreous blast-furnace 

 slags, in natural silicated rocks, the structure of the base of porphy- 

 ritic rocks, the flower structure in ice, and the structure of precipitated 

 carbonate of lime. The latter series of investigation is necessarily 

 incomplete, owing to the death of the author. It is noticeable that he 

 inclined to the belief that the so-called eozoonal structure and the 

 coccohths of chalk may be perfectly paralleled in precipitated car- 

 bonate of lime formed by the action of carbonate of ammonia upon 

 chloride of calcium. The illustrations comprise careful drawings of 

 the numerous appearances described; and several are coloured. H. B. 



YoGT, Gael. Sur la structure microscopique des roches volcaniques. 



[Microscopical structure of volcanic rocks.] Compt. Rend. 2 sess. 



Assoc. Franc, pp. 362, 363. 

 The writer combats Stoppani's view that the vitreous mass in lavas 

 is formed only at the surface of lava-currents and by secondary fusion 

 at the expense of a mass composed exclusively of crystals ; the two 

 elements, iie says, exist together in lava. He likewise denies the 

 truth of Vogelsang's interpretation of '' Jluidcd structure," which he 

 says is to be found not only in certain lavas but also in the siliceous 

 deposits of the Icelandic geysers. This structure is due, according to 



