502 



METALS. 



METEORIC STONES. 



tained the same, but that of the iron is made 

 to vary, the tension of the hydrogen is less as 

 the temperature of the iron increases. At 

 200 Cent, the tension of the moist hydrogen 

 =100 mm. ; at 260 it is 68.8 mm. ; at 360, 

 45mm.; at 440, 30.4 mm. ; at 860, 17.7 mm. ; 

 at 1,040, 13.5 mm. ; and at the melting-point 

 of iron, 9.7 mm. 5. The higher the tension 

 of the water-vapor, the temperature of the 

 iron remaining the same, the higher is the ten- 

 sion of the hydrogen, and, as the tension of the 

 vapor increases, the increase of tension of the 

 gas is more than proportionate, the difference 

 of increase becoming less and less, however, 

 as the temperature of the iron is raised. 6. All 

 these laws hold good when a small quantity 

 of hydrogen is allowed to act on a large quan- 

 tity of oxide of iron. M. Sainte-Claire De- 

 ville also accounts for the singular erosion of 

 the iron of steam-boilers by distilled water, 

 by the fact that iron is slowly attacked by 

 steam at 150 0. The oxide formed by steam 

 acting on iron at the temperature of 440 C. 

 has a composition corresponding to Fe 4 B ; it 

 is amorphous, black, magnetic, is scarcely af- 

 fected by nitric or sulphuric acids, but is read- 

 ily soluble in cold hydrochloric acid, forming 

 a deep-brown solution, with which potash 

 forms a black precipitate. The fact is thus 

 clearly elicited, that iron is much more acted 

 on at low temperatures than at high ones. 



Preservation of Sheet-Iron Vessels. Mr. C. 

 Widemann, in the Journal of Applied Chemis- 

 try, speaks approvingly of the arrangement 

 devised by MM. Demance and Bertin to pre- 

 vent the destructive oxidation of sheet-iron 

 vessels by sea-water. Their plan is to trans- 

 form the whole vessel virtually into a kind of 

 large volta-cup battery; zinc holders, in the 

 shape of tanks or cylinders, are placed against 

 the internal sides of the vessel ; these holders are 

 kept in perfect electrical communication with 

 the frame and outside portion of the vessel by 

 saeans of rivets, or any other suitable connec- 

 tions, and are daily filled with salt water; 

 blades of zinc, crossing each other and passing 

 over the outside of the vessel, are also con- 

 nected with the holders ; by the oxidation of 

 the zinc these charge with negative electricity, 

 transmitting it by conductibility to the iron 

 of the vessel, which thus becomes similar to 

 an immense electrode charged with the nega- 

 tive fluid. The authors claim that vessels thus 

 protected, after long voyages, show no signs of 

 oxidation. Says Mr. Widemann : 



These experiments suggested to M. Schussler, of 



oxidized, and having applied the principle of MM 

 Demance and Bertin, by connecting the piece of 

 sheet-iron with a small blade of zinc, the oxidation 

 was prevented, and this piece, although having been 

 in brine for over seven months, has not yet shown 

 the least sign of oxidation ; I believe that the same 

 principle could be applied to all iron-work exposed 

 to sea-water, or even in moist soil; gas-posts in 

 streets might also be thus prevented from oxidation. 



METEORIC STONES. On the 25th of May, 

 1871, about 8 p. M., a meteoric stone fell in 

 the southern part of the town of Searsmont, 

 Me. Persons in the vicinity, in the open air, 

 heard an explosion like the report of a heavy 

 gun, followed by a rushing sound, resembling 

 the escape of steam from a boiler. The stone 

 descended in a field, penetrating the hard soil 

 to the depth of about two feet. It was quite 

 hot when taken out, and so much broken that 

 it could be removed only in pieces. The out- 

 side plainly showed the effect of melting heat. 

 The largest fragment weighed two pounds, and 

 the total weight of the pieces obtained was 12 

 pounds. They emitted the odor given off by 

 stones when violently rubbed together. The 

 character of the soil was a hard, coarse gravel, 

 and the shattering of the stone was produced by 

 it finally meeting three large pebbles in its course 

 into the ground. About two minutes seemed 

 to elapse between the first report and the 

 striking of the earth by the stone. The report 

 was audible at Warren, 12 miles to the south- 

 west, but not in Searsmont village, three miles 

 to the northeast. Such are all the important 

 facts that could be gathered about the descent 

 of the Searsmont meteorite. The two-pound 

 fragment was placed in the hands of Prof. C. 

 IT. Shepherd, for analysis. Fully one-half of it 

 at that time was covered with its original 

 crust. Its shape would seem to denote an 

 oval, subconical figure, in the original mass, 

 with a flattish base. Its composition proved 

 to be as follows : 



Nickeliferous iron 14.63 



Magnetic pyrites 3.06 



Olivine 43. 04 



' Bronzite, a hornblende, with a little albite 



or orthoclase, and chrome iron 39.27 



With the bronzite there may. also be enstatite. 

 which would be confounded with the former, 

 if existing in the stone. 



Prof. J. W. Mallet publishes in the American 

 Journal of Science the results of his analysis 

 of three lumps of meteoric iron, weighing re- 

 spectively 56 Ibs., 36 Ibs., and 3| Ibs. picked 

 np at different times in Augusta County, Ya., 

 the two larger ones near Staunton : 



gas 



sheet-iron, and, as the Metropolitan Gas Company 

 used the salt Hudson-Kiver water in their gas-holder 

 tanks, the oxidation was very rapid, destroying the 

 iron, and preventing the coat of paint from adhering 

 to the sheets. 



In our first experiments, we introduced small pieces 

 of sheet-iron into diiferent liquids and water at dif- 

 ferent degrees of strength as to the quantity of salts 

 dissolved in them ; the sheet-iron very soon became 



