180 



THE GEOLOGIST. 



is to be added salt of phosphorus ; and thus, after continued heating, the siHceous 

 earths may be recognized in the shape of beads or points. The analysis by the 

 moist way may be performed either with acids or water. Water can only dissolve 

 a few natural salts, as, for example, rock-salt, alum, carbonate of soda, sulphate 

 of soda, potass, salts of magnesia, protoxide of iron, oxides of copper and tin and 

 lime ; the solution of each of these has a peculiar taste, and when evaporated in a 

 watch-glass, leaves behind the dissolved salt, which may now be readily analysed 

 by the ordinary chemical process. 



" The acids act on several compounds of silica, especially such as contain water 

 (the hydrous silicates), as, for instance, the zeolites ; they have also a solvent 

 action on calcareous felspar, so that the silica separates like a jelly or slime ; 

 other silicates must first be melted, or mixed with alkalies, if they are to be 

 further examined. On the other hand, the acids dissolve most metallic oxides, 

 with a determined colouring, which is indicated to some extent in the accounts of 

 the individual minerals." 



The relations of the chemical constituents to crystalline forms is admirably 

 set forth in the same easy and definite manner ; and the chapter on this 

 subject contains a valuable table, displaying the Latin and English names, the 

 symbol, electrical relations, the atomic weight, specific gravity, colour and appear- 

 ance, modes of occurrence, &c., of minerals. The minerals noticed are also 

 described in the same terse and explicit way, and for the student this must be 

 regarded as one of the best, if not the very best, elementary treatise. All it 

 teaches is necessary to be known, and to be relied upon, while he has neither to 

 wade through a mass of irrelevant matter, nor to learn under the dread of having 

 to reject, on future reading, anything he has, from this book, acquired. 



On Copper-Smelting. By Hyde Clarke, C.E. London : Mining Journal Office, 

 Fleet Street. 8vo. 1858. 

 This pamphlet, a reprint of a report of a paper read before the Society of Arts, 

 contains much valuable information on copper-smelting, and a considerable 

 amount of statistical details of the copper-trade. 



A New Geological Chart, sTioioing at one view the Order of Succession of the Stratified. 

 Bocks, with their Mineral Characters, Principal Points, Average Thickness, 

 Localities, Uses in the Arts, <L'c. Arranged by John Morris, F.G.S., 

 Professor of Geology in University College. London : James Reynolds, 

 174, Strand. 



In our last number we noticed one of the many admirable tables and sections 

 for the publication of which Mr. Reynolds, of the Strand, is so well known, and 

 it is with much pleasure we notice this tabular chart, which we have received as a 

 new publication since our last issue. 



What the title professes the work fulfils. We have, in the centre, coloured 

 spaces, in which the succession of the beds and their thicknesses are duly 

 registered and supported, on the one hand, by concise descriptions of their uses 

 in^ the arts, and their mineral characters ; on the other, by some half-dozen names 

 of the characteristic points of each division, and the like number of localities in 

 which each division is typically displayed. 



Little is necessary to be said of such works, and we feel ourselves only called 

 upon to recommend them, or point out their defects, for the benefit of oui' nume- 

 rous readers. Of this chart, we would say that it is worthy of a place alike in 

 the library of tlie student or the proficient in geological science, and that we are 

 pleased to find that Professor Morris has modified the nomenclature of the 

 ditlerent divisions of the Crag, in a manner to rectify the objectionable terms 

 hitherto in use, to which we alluded in our notice of his former production. 



