1822.] Prof. Berzelius on the Blowpipe. 389 



columbium, then recently discovered, and of which he sent him 

 a small specimen, Gahn immediately found that it contained tin, 

 although that metal does not exceed 1-lOOth of the weight of 

 the mineral." To this he adds, that long before the question, 

 was started, whether the ashes of vegetables contain copper, 

 '^ 1 have seen him many times extract, with the blowpipe, from a 

 quarter of a sheet of burnt paper, distinct particles of metallic 

 copper." 



These facts are worthy of particular notice, and they oiFer 

 great encouragement to those who have hitherto neglected the 

 use of the blowpipe, or have rejected it as difficult, to renew their 

 attempts. 



The parts of which the book, or rather the translation, con- 

 sists, are: The translator's dedication to Sir H. Davy; — his 

 preface and a note to the reader, explaining and rectifying some 

 mistakes, induced by Berzelius's hypothetical notions of combi- 

 nation, and his attempt to reconcile the theory of volumes with 

 the atomic or corpuscular theory. We have then a sketch of 

 Berzelius's mineralogical arrangement by the translator. This 

 is followed by the author's introduction, and the remainder, 

 constituting of course the greater part of the work, is arranged 

 under the following heads : Description of the blowpipe, includ- 

 ing the flask, flame, and support ; the reagents, and their use, 

 follow ; and of these a very complete account is given. We have 

 then the pyrognostic characters of the alkalies, earths, and 

 metallic oxides, detailed : these are followed by the characters- 

 of minerals ; and the work concludes with an account of the,- 

 phsenomena developed by urinary calculi before the blowpipe. 



It is to be observed that Mr. Children has introduced a very 

 useful Synoptical Table of the principal characters of the pure 

 earths andmetalHc oxides before the blowpipe. 



It may not, perhaps, be uninteresting to the reader, to have an 

 example of the mode in which mineral bodies are treated in this 

 work : we give at hazard : 



" Phosphate of iron in bluish transparent crystals, from St. Agnes^ 

 in Cornwall. 



^' A/one, in the matrass, gives a great deal of water, intumesces, 

 and becomes sprinkled with grey and red spots. 



" On charcoal J intumesces, reddens by the heat, and then very 

 readily fuses into a steel-coloured globule, with a metallic lustre.. 



" With borax and salt of phosphor us, heh2ive& like oxide of iron. 



*' With soda, on charcoal, in the reducing flame gives grains of^ 

 iron, which are attractable by the magnet. On platina foil, there 

 is no indication of manganese. 



" With horacic acid dissolves readily, and by the addition of 

 metalHc iron, in the manner detailed at p. 129, gives a fused 

 regulus of phosphuretofiron. 



" All the varieties of phosphate of iron that I have had aa 

 opportunity of examining, behave in the same manner " 



