208 ON THE ASSAYING OF COALS BY THE BLOWPIPE. 



great mass of sedimentary strata permeated by water. As heat from 

 beneath invades these sediments, it produces in them that change 

 which constitutes normal metamorphism. These rocks at a sufficient 

 depth are necessarily in a state of igneo-aqueous fusion, and then in 

 the event of fracture of the overlying strata, may rise among them, 

 taking the form of eruptive rocks. Where the nature of the sedi- 

 ments is such as to generate great amounts of elastic fluids by their 

 fusion, earthquakes and volcanic eruptions may result, and these, 

 other things being equal, will be most likely to occur under the more 

 recent formations. 



ON THE ASSAYING OF COALS BY THE BLOWPIPE. 



BY E. J. CHAPMAN, 



PEOFESSOE OF MINEEAIOGT AND GEOLOGT, TJNIVEEaiTT COLLEGE, TOEONTO. 



Read before the Canadian Institute, IQth January, 1858. 



The blowpipe had been employed with great success for nearly a 

 century in the examination of minerals and chemical products, with a 

 view to distinguish these numerous bodies from one another, and 

 also to ascertain their general composition, when Edward Harkort of 

 Freiberg first applied it to the quantitative investigation of certain sil- 

 ver ores and furnace products. Plattner, who had worked with Harkort, 

 subsequently extended this application to the assaying of various me- 

 tallic substances, and added in no small degree to the utility of the in- 

 strument, by the invention of new methods of research and many new 

 appliances, published collectively in his well-known Probirkunst mit 

 dem Lothrohre.* No one, however, has yet attempted to employ the 

 blowpipe in the practical examination of coals, an application pecu- 

 liarly fitted to it : since, in travelling, and at other times when c>nly 

 the blowpipe-apparatus can be conveniently made use of, determinations 

 of the kind in question are often desirable. Having had some experi- 

 ence in the use of the instrument, I have attempted to supply this 



• This work reached m 1853 its fourth edition. Harkort's earlier publication (1827), of 

 which, however, merely the first part was issued, bore a similar title. For all that concerns 

 the history and general application of the blowpipe, the reader may consult the fourth edi- 

 tion of the standard work by Berzelius, as translated by Whitney. A new edition of this 

 work, incorporating the various tests and discoveries published since the death of its dis- 

 tinguished author, is much required. 



