500 



METALS. 



should be as hard as the case will admit, of an even, 

 close grain, and with the carbon combined and not 

 in the form of graphite. Impure, soft foundery-iron 

 will corrode rapidly ; close-grained gray iron, of an 

 even texture, will resist corrosion in the most ex- 

 posed places without sensible injury, and white iron 

 of good quality may, for all practical purposes, be 

 considered as imperishable in such situations. 



Care should also be taken not to place iron in con- 

 tact with other metals, so as to produce galvanic ac- 

 tion. 



It is well known that many cast-iron water-mains 

 have corroded greatly, not only externally but in- 

 ternally. In the latter case, the oxidation sometimes 

 takes the tubercular form, where the rust is collected 

 and aggregated in hard knobs. 



In the early manufacture of water-pipes, they were 

 often made from the worst quality of metal ; it could 

 hardly be called iron, but was a composition of cin- 

 ders, sand, scoria, and iron of the softest kind, loose- 

 grained, and in large crystals ; indeed, precisely such 

 a mixture as would offer the least resistance to cor- 

 rosion. 



"Water-pipes placed in the streets of a city in earth 

 alternately wet and dry, and saturated with mephitic 

 gases from sewers and gas-pipes, are exposed to cor- 

 rosion more than under almost any_ other circum- 

 stances, and, if made of the material just stated, will 

 be destroyed, where those of a proper quality of 

 metal would endure a very long time. The internal 

 corrosion, however, where the iron is exposed onljr 

 to the action of pure water and a small amount of 

 air in combination, will not occur to any appreciable 

 degree, if the iron is of the proper quality. 



The strength of cast-iron pipes, of the usual thick- 

 ness, is so far beyond the pressure of the water and 

 occasional percussions, that the manufacturers seem 

 to think that the weakest metal will ansAyer ; and 

 the engineers have not yet, in their specifications 

 and inspections, required enough care in the selec- 

 tion of the metal best calculated to withstand cor- 

 rosion. 



Phosphorus in Iron and Steel. A new 

 method of analyzing iron and steel, to deter- 

 mine the amount of phosphorus present, is rec- 

 ommended by Mr. F. Kessler, in a paper read 

 before the Chemical Society of Berlin. It is 

 briefly as follows: 5.6 grains of the substance 

 are digested with nitric acid evaporated to 

 dryness, strongly ignited, dissolved in hydro- 

 chloric acid, reduced with sulphuretted hydro- 

 gen gas, treated with a solution of 72 grammes 

 of ferrocyanide of potassium, the whole diluted 

 to 518 cubic centimetres, allowing 18 c. c. for 

 the volume of the precipitate ; 250 c. c. of the 

 nitrate from the above are measured off, and 

 sulphate of magnesia and aqua ammonia are 

 added to precipitate the phosphorus, which is 

 afterward determined as pyrophosphate of 

 magnesia in the usual way; one decigramme 

 of the magnesium phosphate indicates one per 

 cent, of phosphorus in the iron. The author 

 prepared a series of test-mixtures of known 

 constitution, varying from one per cent, to 

 0.020 per cent, phosphorus, in order to prove 

 the accuracy of the method, and gives the fol- 

 lowing table of results : 



Three samples of iron were analyzed accord- 

 ing to the old and new process. A, soft cast- 

 iron; B, white cast-iron with 12.5 per cent, 

 manganese; C, steel. Phosphorus obtained : 



Action of Fluor-spar on Cast-Iron. At- 

 tempts to apply fluor-spar alone to ordinary 

 cast-iron have been failures, hut the same sub- 

 stance acts energetically on cast-iron contain- 

 ing titanium, turning the metal into wrought- 

 iron, after proper treatment in a cupola. Mr. 

 James Henderson writes to Nature to prove 

 that, by the action of fluor-spar, nearly all the 

 impurities in titaniferous cast-iron may be re- 

 moved. He reports : 



One ton of Cleveland pig-iron was melted in a cu- 

 pola with 7 cwts. of Norwegian titanic iron-ore, con- 

 taining, by analysis, about 40 per cent, of titanic 

 acid. The resulting metal was titaniferous cast-iron, 

 analyzing: 



Titanium 1.2551 



Silicon 1.8139 



Phosphorus 



Sulphur 



Carbon 



Hence it appears that the iron, by being remelted 

 with titaniferous iron-ore, took up 1.25 per cent, of 

 titanium, and lost 0.90 per cent, of phosphorus, and 

 1.75 per cent, of carbon. It is obvious that the metal in 

 this condition is not available for any purpose without 

 subsequent treatment, as it contains about as great 

 an amount of impurities as it did before treatment. 



The advantages gained by remelting the pig-iron 

 with titaniferous iron-ore are, a reduction of the 

 amount of phosphorus and carbon, and the alloying 

 of the metal with titanium, which facilitates the re- 

 moval of the impurities in the subsequent treatment. 

 The above-described titaniferous cast-iron was re- 

 melted upon fluor-spar, and about thirty minutes af- 

 ter the iron melted, or in about an hour after they 

 were both charged, the iron was found to be malle- 

 able iron ; the button analyzing as follows : 



Titanium 0.0215 



Silicon None. 



Phosphorus 0.1399 



Sulphur 0.0620 



Carbon Traces. 



When worked on a larger scale, so as to produce 

 blooms that can be worked into merchantable shapes. 

 the finished results will show less phosphorus and 

 sulphur than the above analysis. 



Russian Sheet-Iron. In a work published 

 during the year, devoted exclusively to this 

 topic, Mr. John Percy removes the mystery 

 from the manufacture of Kussian sheet-iron. 

 The malleable iron is derived from pig-iron 

 obtained by smelting the following ores in 

 cold-blast furnaces magnetine, carbonate of 

 iron, and red and brown hematite. The con- 

 version is effected either in the charcoal -finery 

 or in the puddling-furnace. The puddle-balls 

 are rolled into bars 5 in. wide and J- in. thick. 

 Eeheating is conducted in furnaces of peculiar 

 construction. The rolls are driven by water- 

 wheels, and should make not fewer than 50 

 revolutions a minute. The hammer-hea(]s nre 

 of wrought-iron, and the anvils solid blocks 

 of white cast-iron. The puddle-hars, after 



