418 OBSERVATIONS IN CHEMISTRY AND MINERALOGY. 



Verv dark ruby ring surrounded by aureole. 



1 (g) Blank glass space. 



(h) A gray ring. 



(i) A pale gray ring. 



(k) A bright yellow film. 



Note 1. — The rings at a and / are exactly above the ends of the wires. They 

 suggest a maximum bombardment of copper particles. Why? Is perhaps 

 the metallic cohesion less at the chipped ends than over the cylindrical surface? 



Note 2. — The yellow sublimate is puzzling; it is not a compound of copper* 

 too small a quantity of material to establish its nature. 



XXXVII. The same bundle of wire was placed in a new tube; was oxidized 

 at 460° C. during 1 hour ; deoxidized at 690° C. for 2 hours. No indication of ruby 

 color whatever. 



XXXVIII. Repetition of XXXVI ; only the surface of the wire was scraped 

 with a knife edge and then burnished with charcoal and chamois leather. The 

 ragged ends were cut smooth. Oxidation lasts three hours and deoxidation one 

 hour. Strong development of ruby and a yellow sublimate. A replica of note 36, 

 only there are no maximum bands a-f over the ends ; the maximum is in the middle 

 rather. 



3. The Action of Sulfurdioxyd on Cuprisulfate Solutions in a Sealed 



Tube at Different Temperatures. 



This investigation was brought about in March, 1910, by the activity of a 

 Chicago party in offering stock of a company which was to leach a sandstone or 

 other siliceous rock with dilute sulfuric acid. The rock is said to contain all its 

 copper as carbonate and this was therefore an ideal condition. The solution 

 was then to be treated in suitable tanks— lead-lined— with sulfur dioxyd under 

 heat and pressure. The copper would all be precipitated as metal and the mother 

 liquor could be used to leach out a fresh portion of rock. The question was not 



theoretical but rather practical at first and was submitted to me as follows 



Will S0 2 precipitate a copper sulf ate solution completely and if so wwfer what 

 conditions? There are four principal possibilities along the line of the following 

 equations : 



(a) Cu(S0 4 ) + S0 2 + 2H 2 + water - Cu + 2H 2 (S0 4 ) + water. 



(6) 2Cu(S0 4 ) + S0 2 + 3H 2 + water m Cu 2 + 3H 2 (S0 4 ) + water, 



(c) Cu(S0 4 ) + S0 2 4- H 2 + water = Cu(SO.) + H 2 (S0 4 ) + water 

 (d) 



Cu(S0 4 ) + S0 2 + H 2 + water = Cu(S0 3 ) + n^ u *> T nav 

 2Cu(S0 4 ) + 2S0 2 + 3H 2 + water = Cu',(SO,) + 3H 2 (S0 4 ) + water. 



Transposing these symbols into words we say : it is possible to form mtm °°^ 

 or cuprite, or cuprisulfite, or cuprosulfite according to temperature, 

 predominance of sulfurdioxyd or its lacking. 

 The following experiments were made. 



