1917] Forbes: Irrigation Effects of Copper Compounds Upon Crops 407 



in low-grade sulphide ores (No. 3491, No. 3303), and to nearly 

 one-half in the richer oxidized ores (No. 3492, No. 3304, No. 

 3439). By far the larger portion of tailings produced, however, 

 are from low-grade sulphide ores, the wastes from which there- 

 fore predominate, formerly imparting to river waters the whitish 



TABLE III 



Dissolved Copper in River, Irrigating, and Ground Waters below the 



Clifton-Morenci District 



Condition and 



amount taken 



in cc. 



500 



Sample No. 

 and date Description of sample 



3438 Water mixed with sulphide tailings 

 June 28, '05 from A. C. Co. ' s mill, Clifton 



3439 Water mixed with oxidized tailings 



June 28, '05 from A. C. Co.'s mill, Clifton 500 



3309 Montezuma Canal water at Solo- 

 May 26, '04 monville; slight rise in river 2000 



3486 Montezuma Canal at Solomonville, 

 June 11, '05 small flood 6000 



3622 Montezuma Canal at Solomonville, 

 June 25, '06 head waters clear 9000 



3737 Montezuma Canal at Solomonville, 

 Feb. 22, '07 medium flood 14000 



Tailings shut out of water supply May 1, 1908. 



4011 Water from Montezuma Canal at 

 Jan. 3, '09 Solomonville 



4029 Montezuma Canal at Solomonville 

 Apr. 12, '09 



6342 Montezuma Canal at Solomonville, 



Mar. 4, '16 high water 



3986 Water from C. & A. Ditch, Bisbee 

 Jan. 2, '09 mine waters 



Records of 



Cananea 



C. C. Co. Water from creek below concen- 



Jan. 4, '14 trator 



Water from Geo. Olney 's well, 30 ft. 

 deep, east of Safford, under 

 Montezuma Canal 



Water from Wilson's well, one-half 

 mile west of Solomonville under 

 San Jose Canal 



Water from University well, Tuc- 

 son, 95 ft. deep, tapping Rillito 

 underflow 



4000 

 3700 



1000 



3500 



3504 

 Aug. 19, '05 



4012 

 Jan. 3, '09 



3526 



7000 



3500 



Cu 

 found, 

 grams 



.0009 



.0018 



.0016 



.0015 



.00095 



.0403 



.00031 

 .0003 



.00003 

 .00039 



7000 



.0037 



less 



than 



.00001 



none 



Cu 

 p. p.m. 



1.80 



3.60 



.80 



.25 



.11 



2.88 



.08 

 .08 



.03 



.11 



2.1 



.53 



less 

 than 



.oo.-? 



none 



appearance characteristic of this material. It is of interest to 

 note in this connection that in one instance observed the tailings 

 almost completely maintained their richness in copper between 



