CGPRIC OXYSULPHATES FItOM CORNWALL XVI.-On some Hydrated Cupric Uxysukhatesfrom Cornwall. ByA. H. CHURCH. ZyeZlite.-Not very long after his announcement of “Larzgite ’’ as a new mineral species from Cornwall Prof. Maskelyne pointed out. a second copper compouud from the same locality as distinct. This species he termed “Lyellite.” Three months later 35. Pisani gave an analysis of the same mineral; it will be found in the Comptes Rendus of Nov. 14th 1864. M. Pisani re-names the mineral ‘‘Devilline,” and deduces for it the formula :-(CuCaFe),S + 3aq. I purpose to employ the name Lyeltite as having priority. I have received from Mr. Talling a portion of the same speci-men of lyellite as that analysed by M. Yisani and have submitted it to analysis. It is unnecessary to repeat in detail the physical and chemical characters of this new species of Prof.Maskelyne’s; it will suffice to say here that the analysis of this mineral presents CHURCH ON SOME HYDRATED some peculiar difficulties. For intermixed with the true lyellite which occurs in concretionary crusts of a very pale bluish white tint and satiny lustre is a darker blue mineral apparently langite. This impurity occurs in layers and is irregularly dis- tributed in the whiter mineral ; these layers are sometimes in the direction of the radiation sometimes across it. Fortunately the blue mineral being in loosely coherent masses of minute crystals may be almost completely removed by breaking the mineral into small fragments and carefully brushing these with a fine sable pencil.In this way my specimen was prepared for analysis but it was not quite pure even then. I believe the only impurity was the blue mineral and assuming this as is most probable to be langite the discrepancies between the theoretical and experimental percentages are explained. Lyellite contains copper calcium a sulphate and the elements of water. It contains also a minute trace of iron so minute as to give no distinct reaction when a few grains of the mineral in solution were tested with potassic ferri- cyanide; and even after oxidation the ferro-cyanide gave a faint blue coloration only. The following are the results of the analysis of lyellite :-03245 gramme lost in vacuo 0002gramme H,O -3225 , gave 0184 , BaSO 03225 , > 0045 , CaCO 03225 , ,> -165 , CuO These numbers correspond to the following percentages :-Hygroscopic water $62per cent.23.50 ,, so3 CaO. 7-81 , CUO. 51.13 , I have said that M. Pisani proposes for this mineral the for- mula-(CuCaGe),S + 3aq. We have however seen that it contains no iron and the results of my analysis which agree closely with those obtained by M. Pisani correspond to a slightly modified formula. Annexed are the theoretical and experimental percentages. CUPRIC OXYSULPHATES FROM CORNWALL. Theory. Experiment. (CuCa2S04.3CuH202.3aq.) Pisani. Church. 4CuO .... 318 49.53 51.01 51.13 CaO .... 56 8-72 7.90 7.81 2S03 .... 160 241.90 23.65 23.50 6II,O .... 108 16.95 16-60 16.88 (by diff.) 64.2 lOO*OO 99.16 0.68 (impurities).FeO 2-77 100.00 101.93 It will be observed that the cupric oxide is in excess while the calcium-oxide and sulphuric anhydride are deficient ;the assumed admixture of the lyellite with a mineral evidently (from its deeper blue tint) richer in copper will account for all these discrepancies- a very small percentage of langite would in fact produce this result. Brochantik-A mineral which appears to have the chemical characters of brochantite has been lately found in Cornwall. M. Pisani announced this discovery in the Comptes Rendus for Nov. 28th 1864. Several formulae have been proposed for the native and the artificial brochantites but it has been remarked that this basic sulphate oscillated between- CilS0,.2CuH,02 and CuS0,.3CuH202 ; my analysis points in the same direction; it suggests however the intermediate formula- 2CuS0,.5CuH202.Before giving the analytical results it may be stated that the brochantite often accompanies langite the latter mineral being then seen as a scattered blue crust upon the dark green or emerald-green brochantite. I fear that the crystals in my specimens are too small and confused for accurate measurement. They are transparent and occur in groups of slender wedges tapering tow:uds either extremity. Two of the boundaries of each crystal appear curved. Since my preliminary note on Cornish brochantite appeared in the Chemical News (Feb. loth 1865) this mineral has been described under the name of Waringtoni te by Professor M ask e 1 y n e ; it is unnecessary therefore to repeat here the physical characters of the substance; I will merely give the analytical results and the formula they CHURCH ON SONE HYDRATED suggest.It ought to be stated that the utmost care was taken to obtain a homogeneous sample for analysis. The brochantite occurs upon decomposing elvan but immediately underneath the cupric crust a considerable quantity of ferric oxide occurs. An impure cuyreous wad also occasionally accompanies the brochantite. 6.73 grains lost *07grains at ,260' C. 5.17 , gave -03 , insoluble residue 5.17 , , 2.85 ,) BaSO 6.73 , , 4.62 ,) CuO 5.17 , , 3.51 , CuO. Before the mineral was submitted to analysis it was placed over oil of vitriol in vacuo; but by this treatment it suffered no appre- ciable loss.Below are given the percentage numbers deduced from the foregoing analyses. In the first column the percentages are those deduced directly; in the second column the calculations have been made after subtraction of the water lost at a temperature not exceeding 260° C.,* and of the insoluble matter :-CuO. ................ 68.27 69-32 SO .................. 18.93 19.24 H,O.. ................ 11.18 11.44 H,O lost below 260' .... 1.04 -Insoluble matter. ....... *58 100-00 100~00 The formula 2CuSO4.5CuH,O, requires percentages closeIg corresponding with those deduced from the analyses :-Theory. Experiment CUO.. .... 69.00 69.32 SO,. ..... 19.84 19.24 H,O. .....11.16 11.44 The differences it will be observed all lie in the diivection of the probable experimental errors. In an analysis not recorded above 6.73 grains of the mineral gave 8-39 grains of BaSO ;this corre- sponds to 17.3 per cent of SO,. But with the lower estimate of the SO, the total percentage of water in the mineral calculated by difference amounts to no more than 13.48; in the second analysis it is only 1.2.6. These numbers exclude the formula CuS0,.3CuH,02.aq. which demands 15.34 p.c. H20 as the fol- lowing comparisons show. It must be remembered that the * Some specimens lose nothing at thiB temperature. CUPRIC OXPSULPIIATES FROM CORNWALL. mineral under review loses sulphuric acid as well.as water when heated sufficiently to deprive it of all water; the water in it is retained even at 260"-270°C.f 1. Theory. 11. 111. ' F I. Experiment. J-11. 111 Cu304 3CuH,02. CuSOl 2CuS04 3CuH20-aq. 5Cu H,02. Pisani. Msskelpe. Church. CuO . . 70.36 67.62 69.00 70.06 68-24 69-32 SO . . 17.70 17-04 1984 17*52 16.73 19.24 H20 . . 11.94 15.34 11-16 13.42 14.64 11-44 Collating the recent with the older analyses of Brochantite,* there seems some ground for the opinion that at least two sub- stances chemically distinct have been included under one name. If such be the case Prof. Maskelyne's Waringtonite might be separated chemically as well as crystallographically from Brochan- tite although his proposed formula (11.above) is negatived by both of my analyses and as well as by those of M.Pisani. One hesitates indeed between the formul2e I. and III. but it is pos-sible that M. Pisani may not have analysed the true xedge- shaped crystals of so-called Waringtonite but the commoner form of Brochantite occurring in the same locality. For the analysis of the variety or species Waringtonite I am indebted to my assistant Mr. R VC'arington junior. Langite.-According to M. Pisani langite has the formula CuS0,.3CuH202. ag. the very expression assigned to Waring-tonite by Prof. Maskelyne. My own results confirm those of Af. Pisani. A few words are necessary as to the material sub- mitked to analSsis. Langite appears both in miniite prismatic crystals of a fine blue colour and also as a foliated crystalline mass. The latter form is the more abundant and having freed some specimens of it from a few imbedded crystals of the deeper colour I submitted them to analysis with the following results :-a.1-024 gramme lost in vacuo -004gramme H20 Air 1.024 , gave ,691 , CUO 9, dried. { 1.024 , -501 , Bas04 6. 14.09 grains lost at looo C *12 grains H20 Vacuum 14.09 , below redness 2.29 , H20 dried. i14.09 , gave 6.86 , BaSO * Rammelsberg's Minerakhemie (1860),p. 268. CHURCH ON SOME CUPRIC OXYSULPHATES. C. 12.3 grains gave 8.35 grains Cuo 1000 c. I made the analyses of a; b and c were analgsed by Mr. War-ington. The following are the percentages deduced from the several analyses calculating the results on the vaconm-dried sub-stance and also on the substance as dried at 100°C.:-Dried in vacuo. Dried at 100°C. A. H. C. R. \V. R. W. CuO .. 67.48 67.31 67-88 SO .. 16-79 16-72 16.88 H,O .. 15.73 16.25 15.53 100~00 100.28 100.29 These nurn hers correspond very closely with those required by the formula CuS0,.3CuH20. aq. :-Mean (vacuum dried). 4CuO .. 318 = 67.65 6740 so .. 80 = 17-02 16-76 4H,O .. 72 = 15.33 15.89 470 100*00 100.05 The results of independent analyses by M. Pisani Mr. W aring-ton and myself are so exactly accordant that there cannot be the slightest doubt that the blue folk said to be langite are definite in composition and that the formula expressing the com- position of the mineral is CuS0,.3CuH,02.aq. All the slight differences between the theoretical and experimental percentages lie in the direction of the several probable errors; and the loss of water in vacuo amounting to no more than -39 per cent.it canuot be said that the mineral has been altered by the method of desic-cation adopted. The total amount of impurities in the mineral was found by experiment to be very insignificant yet if allowance had been made for it a still closer coincidence between theory and experiment would have been shown. It is scarcely necessary to add that all the analyses recorded in the present paper were performed with the greatest care; the reagents mere pure and the methods known to be trustworthy.