Scientific Intelligence — Geology and Mineralogy. 181 



mark, and have been raising largely ever since, the entire quantity 

 produced within thirteen months may safely be set down at 10,000 

 tons. The prices obtained in the sales of Burra-Burra ores at Swan- 

 sea already shew an average of something more than ^£23, 16s. per 

 ton ; so that even deducting £8, 16s. per ton for carriage, freight, 

 and charges, the mine may be said to have yielded value equal to at 

 least £150,000, estimated upon the ground (or at grass, as miners 

 would say) ; a*ad all this within the short space of thirteen months 

 from the commencement. Nor is this large amount likely to be a 

 maximum, for the malachite, red oxide, and other rich kinds of ore, 

 have become predominant ; and as the mine is undoubtedly equal to 

 the production of 300 tons or more per week of ores likely to yield a 

 much higher average than heretofore, it is not difficult to foresee the 

 immensity of future returns. The great importance of the operations 

 at this mine, as beneficially affecting the trade and commerce of South 

 Australia, may be judged of from the fact, that the sums already dis- 

 tributed in thirteen months by this one concern, amongst our indus- 

 trious settlers, for carriage alone, must have exceeded £10,000 ; 

 those expended in wages, and the various items of disbursements, 

 £20,000 ; and the British or Colonial freights, which cannot be less 

 than £15,000.— (^i/iewffizm, No. 1072, p. 478, 3Iay 13, 1848.) 



6. O'li an Amorphoits Boracite. — When boring for rock-salt at 

 Neusalzwerk, in the neighbourhood of Minden, in Prussia, at the 

 depth of about 1400 feet, a bed of amorphous boi-acite was found, of 

 which specimens were brought out by the boring apparatus. The 

 chemical analysis, which proves that the composition of the amor- 

 phous mineral is exactly the same as that of the well-known crystal- 

 lised body, was made by Dr Karsten in Berlin, particulars of which 

 may be seen in the monthly reports of the Berlin Academy. It 

 seemed to him interesting to examine if that uncrystallised species 

 would shew the pyroelectric quality whic-h, in so high a degree, is 

 to be seen in boracite crystals. Sir D. Brewster has pointed out a 

 way by which the pyroelectric quality of pulverised tourmaline may 

 be shewn. By heating that substance the fine particles cohere to- 

 gether, and shew that a polarisation has taken place in them. The 

 same phenomenon is to be seen in the particles of the amorphous bo- 

 racite by pulverising and heating it on a metallic plate. These bo- 

 racite particles shew, by their pyroelectric properties, that they must 

 be crystallised, although, by microscopic examination, the crystalli- 

 sation cannot be discovered. The conclusion must be, that the dif- 

 ference between the crystallised and the amorphous states cannot be 

 exactly determined, since the microscopic shews, in this case, no 

 crystallisation, where the pyroelcctricity is a proof that we must sup- 

 pose a crystalline structure. 



7. On the Fossil Vegetation of Anthracite Coal. — M. J. E, 

 Teschcmacher, at tlic recent meeting of the American Association of 

 Geologists and Naturalists, read a paper on this subject, confining 



