CHEMISTRY. 255 



of rivers. It has been observed, that sheathing generally wears very rapidly 

 at the mouths of certain rivers ; but if the obsei rations have been made, we 

 have not seen them made public, whether the wear under these circum- 

 stances was general over the whole sheathing of the ship, or on certain parts, 

 either near the surface or near the bottom, because a vessel, lying at the 

 mouth of a river, will be floating in water of different densities, which will 

 set up a galvanic action between those parts of the ship, and thus necessitate 

 a greatly increased action upon the metals. This may be easily tested by 

 taking a tall glass vessel, filling it half full with sea water, and then gently 

 filling with ordinary river water, taking care not to mix the two from top 

 to bottom ; then insert a slip of clean copper, and the action in a short time 

 will be seen to be different on different parts of the copper, and greater on 

 some parts than it would be if placed in a well mixed solution of the same 

 density. 



OX THE COMPOSITION OF SOME VARIETIES OF FORGED IRON. 



The following paper on the above subject has been published by Mr. F. A. 

 Abt-1, Director of the Chemical Establishment of the English War Depart- 

 ment. 



The Government having now taken the manufacture of iron ordnance into 

 its own hand, directed attention first to iron reduced from its ores by charcoal, 

 this being the material exclusively employed in some continental states ; the 

 authorities there laying much stress upon the greater fitness of this de- 

 scription of iron over hot-blast, or even of cold-blast iron, smelted with coal or 

 coke. Experiments were consequently made to ascertain t; whether guns 

 manufactured from charcoal iron exhibit great superiority over those made 

 according to the same system of iron reduced from its ores by mineral fuel." 

 For this purpose, specimens of charcoal pig iron have been collected from 

 different countries for comparative examination and experimental purposes. 

 Of two specimens of white iron from Silesia, obtained from different ores, both 

 were hard and brittle. These irons were proposed for admixture with dark 

 grey irons, but were considered not fit for the purpose. Some French iron, 

 reduced by charcoal from haematite ores, was dark, soft, fine-grained, and uni- 

 form in texture, and its general characters were similar to Swedish grey iron, 

 but superior in reference to the amount of silicium contained. Specimens of 

 Xova Scotian and American irons were of excellent quality. On analysing 

 four specimens of iron gun metal of foreign manufacture, the composition was 

 as follows :^-From Belgium (specific gravity, 7-250); iron, 95-61; combined 

 carbon, -78; graphite. 2'12; silicium, -99; sulphur, -06; phosphorus, '29; 

 manganese, -15. with traces of titanium, chromium, arsenic, zinc, and copper. 

 The French metal showed the same specific gravity: of iron, 9 6 -02; com- 

 bined carbon, 1-03; graphite, 1-87; silicium, -35; sulphur, -03; phospho- 

 rus, -45; manganese, -25, with traces of chromium and tin. From Sweden 

 (specific gravity. 7'05): iron, 95'87; combined carbon, -18; graphite, 2'62; 

 silicium, 1-19; sulphur, -08; phosphorus, -11, with traces of manganese, tita- 

 nium, and chromium. From Russia (specific gravity, 7 -135): iron, 94-36; 

 combined carbon, -47; graphite, 2-83; silicium, 110; sulphur, -02; phospho- 



