COPROLITES 



eubsulphide of copper is produced ; this is converted into sulphate, by roasting in con- 

 tact with air. Large quantities of sulphate of copper are obtained in the process 

 of silver refining, and as a by-product in Ziervogel's method of silver-extraction. 

 Crystallised sulphate of copper contains CuO.SO 3 + 5HO (CuSO 1 + 5H V O). It is 

 largely employed in calico-printing, and as a source of other salts of copper. The salt 

 is also used in certain forms of constant batteries, as Daniell's. 



Several basic sulphates are known, some of which occur native. Cassdman's green 

 is an artificial basic sulphate. See COPPER ; PYRITES ; SILVER. 



COPPER, SULPHIDES OF. At least two distinct sulphides of copper may be prepared. 

 Copper and sulphur when melted together combine with vivid incandescence, anil pro- 

 duce the subsulphide or disulphide (cuprous sulphide), Cu 7 S. This compound also 

 occurs native as copper glance ; and is produced as a regulus in the ordinary process 

 of copper-smelting, when it is called by the smelter fine metal. The higher sulphide 

 (cupric sulphide), CuS, is found native as Covelline, and may be artificially prepared, 

 as a hydrate, by precipitating a salt of copper with sulphuretted hydrogen. The 

 sulphides are decomposed when heated with free access of air; at high temperatures 

 sulphurous acid is evolved, and oxide of copper formed, whilst at low temperatures n 

 sulphate of copper is produced. 



COPPERAS. A common name for green vitriol or sulphate of protoxide of iron 

 (ferrous sulphate). Iron pyrites is also sometimes called copperas. See PYRITES. 



COPROIiITES. (ic6irpos, dung ; \idos, stone). A term properly restricted to 

 fossilized foecal matter. True coprolites usually present the form of ovoid nodules, 

 resembling kidney potatoes, marked on the surface with corrugations, and exhibiting 

 internally a spiral structure due to the form of the intestinal canal through which 

 they have passed. Some of these coprolites were formerly described, from their shape, 

 as fir-cones ; but their true origin was clearly pointed out many years ago by Dr. 

 Buckland. They often contain scales, teeth, and bones, of fish, which represent the 

 undigested portions of food voided in the excrements ; and they are occasionally found 

 in such connection with the skeletons of fossil saurians as to show their original 

 position in the intestines. The coprolites of reptiles and fish are found in many of our 

 Secondary and Tertiary rocks, and are especially abundant in the Lias. These true 

 coprolites consist mainly of phosphate and carbonate of lime. The analyses below by 

 Mr. Thornton J. Herapath represent the composition of a coprolite from the lias strata 

 of Lyme Regis. It was rather large, being above 9 oz. in weight, was of a greyish 

 colour, and when broken exhibited some traces of a crystalline structure. It furnished 

 a greyish-white powder. Many scales of different extinct fishes, and other organic 

 remains, were to be perceived on the external surface ; the greater proportion of them 

 appeared to belong to a species of fish which is known by the name of Pholidophorits 

 limhatus. Its specific gravity was about 2'644 or 2700, and the composition per cent, 

 was as follows : 



* In the first of these analyses, the phosphoric acid was estimated by M. Schulze's method, as pcr- 

 phosphatc of iron ; in the second, as phosphate of lead. 



