96 W. P. Headden — Products found in an old Furnace. 



Stannic Oxide : Artificial Wood Tin. — This consisted of 

 an irregular mass weighing about one and a half pounds. 

 There was a central portion of metallic tin running lengthwise 

 through the mass : at certain points this had entirely disap- 

 peared, but its former presence was shown by the structure of 

 the mass. The oxide has a banded structure, and the banding 

 is at some points plainly concentric. The hardness varies 

 greatly : some portions of the mass have a hardness quite equal 

 to that of the natural wood tin, while others are quite soft. 

 The oxide was reduced in hydrogen to determine the oxygen, 

 and the resulting metal dissolved in hydric chloride for further 

 analysis. The result was as follows : 



Per cent. Atomic Equivalent. Atomic Ratio. 



Sn 76-969 65*2 "| 



Cu 0-240 0-38 ! RKmQ . n _ 



Fe 0-091 0-2 \ 659 10 ° 



Co 0-060 0-1 J 



O _ 22-550 140-9 ' 140*9 2*13 



As Trace. 



99910 

 The manner in which these products may have been formed, 

 the length of time required to produce them, etc., as well as 

 the conditions which obtained at the time of their production, 

 are, unfortunately, almost wholly matters of theory. The 

 formation of the stannic oxide was evidently by oxidation of 

 the metallic tin, a portion of which still remains, but whether 

 aqueous vapor and hot gases, other than the air, had part in its 

 formation is an open question. The arsenide may have been 

 formed in a magma of molten tin, and the tin may have sub- 

 sequently been removed by a process of liquation. There are 

 some indications that this is really what happened, but the 

 extreme cleanness of the crystals is very remarkable if this 

 was the case, the angles throughout the network of crystals 

 being sharp and not filled up with tin, as one would expect. In 

 regard to the stannous sulphide and iron arsenide, I think that 

 their occurrence on the slag is quite suggestive that they have 

 been deposited from an atmosphere furnishing the conditions 

 necessary for their formation. The principal part of the arsenide 

 was deposited first and subsequently the sulphide, but some of 

 the arsenide was deposited both subsequently to and simultane- 

 ously with the sulphide, as the crystals of the arsenide occur 

 implanted upon those of the sulphide, and when the atmos- 

 phere, from which the crystallization took place, furnished the 

 compounds in molecular equivalents, they crystallized together, 

 giving the compound FeAs + SnS. In the masses furnishing 

 the arsenide, there is neither any residual tin recognizable as 

 such, nor sign of flowing, nor yet of absorption by the bricks 

 of the hearth. 



The Laboratory of The State Agricultural College, 

 Fort Collins, Colo. 



