42 EIGHTH REPORT 1838. 



or Lowmoor iron is about 7 per cent, and Welsh iron 6 per cent, lighter 

 than the best Danneniora iron. 



" To analyze Dannemora iron I dissolved 100 grains of it in muriatic 

 acid, evaporated the solution to dryness in a gentle heat, and redis- 

 solved the residue in water slightly acidulated witli muriatic acid. 

 There remained undissolved a gray-coloured matter, which was tho- 

 roughly washed, and dried at a temperature of 300°. It weighed 0*32. 

 gr. or very nearly one-third of a grain. Being ignited in a platinum cru- 

 cible, the weight was reduced to 0"06 gr. of a gray matter, which, 

 examined before the blow-pipe, proved to be silica very slightly tinged 

 with iron. The 0'26 gr. lost by ignition was probably carbon ; for a 

 temperature of 300° was doubtless sufficient to drive off all the water 

 which might at first have been present. 



" The muriatic acid solution Avas mixed with nitric acid and boiled for 

 several hours in a flask, to peroxidize the iron. When cold, the excess of 

 acid was neutralized as exactly as possible by carbonate of soda, taking 

 care that no precipitate fell. It M^as then raised to the boiling point 

 and thrown upon a filter. The whole peroxide of iron which it con- 

 tains is retained upon the filter, and must be well washed with hot wa- 

 ter. At first the water passes through the filter quite coloui'less ; but 

 when most of the common salt is washed out the oxide of iron begins 

 to pass also. To prevent this we must wash it with water containing 

 sal ammoniac dissolved in it : this salt not only prevents the oxide of 

 iron from passing, but the solution of it speedily replaces the conmion 

 salt in the oxide, and thus enables us to wash it much more speedily 

 and completely than we otherwise could do. The oxide being washed, 

 di'ied, and ignited, weighed 142'23 grains, equivalent to 99*56 grains 

 of iron. 



" The solution thus freed from iron was evaporated to dryness by a 

 gentle heat: the residue redissolved completely in water, showing the 

 absence of phosphate or arseniate of iron. The solution being mixed 

 with carbonate of soda, a white powder fell, weighing after ignition 

 0'07 grains. It was brownish red, and being fused with carbonate of 

 soda it exhibited the well-known characters of red oxide of manganese. 

 It was equivalent to 05 grain of manganese. According to this 

 analysis, the constituents of Dannemora iron are 



Iron 99-56 



Carbon 0-26 



Manganese .... 0'05 



Silicon 0-03 



99-90 



"Thus almost the only foreign matter in Dannemora iron is carbon, 

 which cannot be injurious as far as steel-making is concerned ; for the 

 manganese and silicon together amount only to 8 parts in the ten 

 thousand, or not so much as the -j-ynu^'^ part, which could not affect 

 the quality to any great amount. 



" In tiu' Lowmoor iron I found no carbon ; the only foreign bodies 



