Dr Colquhoun on the Argillaceous Ore of Iron. 225 



Ecole des Mines, stimulated to research by the discoveries of 

 Descostils, had verified all his views and reduced his opinions 

 to certainty, it still continued to be maintained that the ores 

 on which they made their experiments did not properly repre- 

 sent any strata, or masses of materials sufficiently extensive to 

 be of importance in a national point of view. But in a matter 

 of such moment to their country, the most eminent chemists, 

 and ingenieurs des mines in France were resolved that truth 

 should prevail over prejudice. And it is perhaps to the* ex- 

 istence of this powerful prejudice that at least one good effect 

 is to be traced, since the investigations of her men of science 

 have procured for France, where the art of metallurgy is yet in 

 its infancy, the best account at present extant both of the chemi- 

 cal constitution, and also of the general history of the argilla- 

 ceous ironstone. The fact at least is undoubted, that within 

 a small number of late years, there have been pubhshed in 

 France not fewer than fifty different analyses of various speci- 

 mens of this ore, although there do not appear to have been 

 more than two similar notices printed in any other country, 

 and just one of these in Great Britain. The German che- 

 mist Freyssmuth, (in Schweigger's Journal J'iir Chemie, *) 

 has related a very careful analysis to which he submitted one 

 specimen of a nodular argillaceous carbonate of iron, and has 

 given at the same time an exact account of the nodule, and of 

 the situation (in a coal formation) in which it had been 

 found ; and Mr Richard Phillips, in the Annals of' Philoso^ 

 phy,-f has stated the result of an analysis of a compact variety 

 of the ore from Yorkshire, distinguished by the provincial ap- 

 pellation of " Black Ironstone." 



The labours of the French chemists, however, amply com- 

 pensate this deficiency. Among their works the most dis- 

 tinguished are, the Essais et Analyses d\m grand nombre 

 de Minerals de Fer, provenant des Houilleres de France^ by 

 M. Berthier, in which this ingenious and indefatigable che- 

 mist has given us the chemical composition, and at the same 

 time a summary description of the external characters of 

 all the specimens of this ore, which, previously to the year 

 1819, had been analyzed in the laboratory of the Ecole des 



* Vol. XX. p. 1. t New Series, viii. 92. 



