398 Prof. N. S. Maskelyne on New Cornish Minerals [1865. 



The analysis of Waringtonite yields numbers that conduct us to the 

 formula 3 Cu" H 2 ' O 2 + Cu" S9 4 + H' 2 O, as the results which follow suffice 



to prove. 



Copper-Determination. 

 grammes. per cent 



i. -1925 yielded (by precipitation) '1054 eopper=54'75 



ii. '334 took 29'20 c.c. of standard solution of hyposulphite sodium . = 54*44 

 iii. -320 ,, 27-40 . =54'252 



Average =54-48 

 Sulphuric Acid-Determination. 



i. -2104 yielded '1001 grm. Ba SO 4 =16'22 SO 3 



ii. -4201 -2060 =16-825 



iii. -3200 -16017 =17'16 



Average =16-73 SO 3 

 Water-Determination 



(3) -4041 amorphous substance yielded when ignited with carbonate of 



barium -0607 = 14-18 



2 '4891 picked crystalline Waringtonite -0777=15'00 



1 -3897 do. do -0503=14-80 



4 -5680 lost when ignited with oxide of lead -0806=14-19 



5 -3707 do. do. do. . -0540=14-56 



Average, omitting the first, = 14-64 



I am indebted to Mr. Madan of Queen's College, Oxford, for the ana- 

 lyses i. and ii. in this Table, and the water-determination in analysis i. of 

 Langite. 



Like Langite, this mineral also contains traces of iron, lime, and mag- 

 nesia. Of protoxide of iron I found in a very pure crystalline specimen of 

 the mineral 0-14 per cent. 



Crystals of Brochantite are often mixed with the Waringtonite, and the 

 more amorphous forms of the green substance would seem to be mixtures 

 of the two minerals. 



The formula 3 Cu" H 2 ' O 2 +Cu"SO 4 + H 2 O requires 



Calculated Average 



percentage. found. 



4 equivalents of copper 12672 = 53' 99 54-48 



4 oxygen 32 = 13-63 (calc. 13756) 



1 sulphuric anhydride 40 = J 7'04 1673 



4 water . . 36 = 15-34 14-64 



23472 100-00 99-606 



Like Langite, Waringtonite, though insoluble in water, is readily dissolved 

 by acids and ammonia, and its behaviour before the blowpipe is similar to 

 that of Langite. 



Its specific gravity is 3'39 to 3'47. 



Its hardness is 3 to 3'5. It abrades calcite, but not Arragonite. When 

 a crystalline fragment is crushed between a cleavage face of celestine and a 



