m BEIKELEY Y : ESTCOURT LIBRARY. -1 - \0 u ELEMENTS OF MINERALOGY, B RICHARD KIR WAN, E% F.R.S. LONDON: Printed for P. ELMSLY, in the M.DCC.LXXXIV. .4T PREFACE. \T 7HEN we confider the degree of excel- * * lence which many of the practical arts bufied in the treatment of Minerals have reached in England^ and alfo that in the merely fpeculative fciences, we are at leaft on a level with our neighbours on the continent, it cannot but be matter of furprize that, with refpecT: to Mineralogy, the parent of thefe arts, they mould ftand confefledly fuperior to us. That this inferiority on our fide does not originate in any want of ingenuity in our artifts evidently appears by the mafterly productions of a 'Parker and a Wedgeivood. The true caufe lies deeper. Mineralogy is an art, whofe cultivation and improvement requires both fpeculation and practice : the mere theorift will never defcend into the la- borious details of the practical part, without due encouragement or a degree of en- thufiafm, in a country devoted to politics rarely to be met with, and the practical ar- tift feldom pofleffes thofe general principle^ of fcience and extenfive acquaintance with the difcoveries of his cotemporaries that are in-* difpenfably requifite to eftablifh him on a footing of equality with them. On the con- tinent Mineralogy is on. a very different foot- ing. In Sweden and Germany it is confidered as a branch of fcience worthy of the atten- A 2 tion \ 033 ii PREFACE. tion of government. There are colleges in which it is regularly taught; it forms a diftinct and honourable profeffion, like that of the foldier, the merchant, or the barrifter ; its fuperior officers form a part of the ad mi- niftration of the ftate. Young ftudents, fraught with the knowledge to be acquired in their own country, are fent abroad to glean all that can be collected from a more diverfi- fied view of nature, or a more improved practice of the arts. This example has been lately followed by the French^ the Ruffians* and even the Spaniards. The French have erected a Mineralogical School at PariSr to which a confiderable penfion is annexed. Subterraneous maps of the whole kingdom are now a tracing, and mineralogical voyages are from time to time undertaken at the public expence *. Chy- miftryv the Parent of Mineralogy, is culti- vated by the moft enlightened nations in Eu- rope> and particularly in France with a de- gree of ardour that approaches to enthufiafm j it forms the favourite occupation, and even the moft fafhionable object of attention not only of the middling, but even of fome in the higheft ranks of fociety f. la * As that of Mr. Jars, &c. •fr Among thefe we may reckon in RuJJla prince GalUtzen. ; in Germany count Sickengen ; in Italy the counts cte Salucei PREFACE* iii In England, on the contrary, (a country far richer than France in mineral produc- tions) it receives no encouragement from the public, and few apply to it except gentle- men in the Medical Line, whofe tranfient at- tention is foon diverted by their more direft occupations. The confequences are obvious. The grofleft blunders are daily committed in working our mines and extracting our ores j infomuch, that learned foreigners have re- marked that were it not for their fuperior ex- cellence, and the cheapnefs of fuel, their ex- traftion would infallibly be attended with lofs f, and many ufeful fubftances are daily rejected as ufelefs, Senfible of our inferiority in this refpecl, and well acquainted with the caufe of it, the zealous and learned Doctor Shaiv, and our late eminent Chymift Dr. Le*wis^ have la- boured to promote and facilitate the ftudy of Chymiftry among us, and for this purpofe transferee! into our own language the moft considerable improvements made in their time de Morozzo^ and the marquis de Gironi, governor of Leghorn ; in Geneva Mr. dc Saujjlire ; in France the dukes de Chaulne^ Rocbefoucault) and D'Jyen ; the counts de Lauragai^ la Garay, Milly, Trcflan, and de la Tour d'Auvcrgne ; the mar- quiiles de Lourtenvaux and de Courtivron j the barons d'Ol- lack and de Servieres ; madame la PrcfJente d* Arconville ; meffieurs Trudaine, La^oifier^ Montigny^ and above all, Mr« deMorveaut one of the firft chymifts of the age. f Ferter, Reife DC rlyjbire. A3 b iv PREFACE, by foreigners. At a ftill later period Mr. Keir has poured upon us many valuable treafures in his excellent notes on Mr. Ma- guer's Chymical Di&ionary, a work gene- rally known, and equally efteemed ; yet fince this work appeared, (the laft of any note among us) fuch rapid advances have been made in the mineralogical art in particular, that it has put on quite a new face. Several new femi metals have been difcovered, the number of primitive earths afcertained, many analyfes accomplifhed heretofore attempted ia vain, and the art itfelf of Mineral Analyfis brought to a degree of certainty and precifioa of which it was fcarcely thought capable. A&uated by the fame views as the patriotic gentlemen juft mentioned, I have endea- voured to collecl: in the enfuing treatife all that has been hitherto done in this fcience, with fome few improvements of my own, modelled and digefted in the method that feemed to me moft ufeful. The point which I principally laboured was not to prefent the reader with a minute detail of the various external appearances of minerals in various countries, nor of their fituation, vicinity, or mixture with each other, circumllances ever contingent and for- tuitous, much lefs to entertain him with prolix and plaufible accounts of their origin, enquiries PREFACE. v enquires which appear to me to belong to an- other branch of the fcience of foffils, viz. Natural Hiftory, but rather to determine the characters by which foffils are invariably and permanently diftinguifhed from each other in all times and places. In a word, rather to define the fpecies than defcribe the indivi- dual; even among thefe permanent charac- ters I have, for the fake of brevity, omitted all, except the moft obvious, a compleat de- tail of them being in my opinion fitter for a treatife ©f Chymiftry than of Mineralogy. The merit of this latter feeming to me to confift in prefenting fuch criteria as may enable us to diftinguifh Minerals in the fhorteft, eafieft, and fureft manner ; fo that we may always apply the lame names to the fame fubftances, and being confident of fpeaking the fame language, may always un- derftand each other. What confufion hath heretofore arifen from the ambiguity of names is well known, and will, I fear, render many very mterefting refearches, even of mo- dern date, intirely ufelefs. Among thefe I ihall only mention thofe of the celebrated Canon Recupero^ who for many years, and with immenfe pains, has ftudied and de- fcribed the Minerals in the neighbourhood pf Mount &tnaf but committed fuch miftakes in their denomination as will, according to the remark of that excellent Mineralogift A 4 Mr* vi PREFACE. Mr- Saujfure, render his work, if ever it ap-* pears, abfolutely unintelligible *. Whether the characters of Minerals fhould be taken from external appearances only, or from their internal properties as difcovered by chymical agents, has long been contro- verted among Mineralogifts ; though, in- deed, at prefent the controverfy feems almoft at an end from the univerfal approbation with which the fyftem of the celebrated Cronfted, founded almoft entirely on chymical charac- ters as far as they were known in his time, has been received by all Europe. However, fome able patrons of the former opinion have appeared of late, among whom I ihall mention only Mr. Werner and Mr. Rome dc Lijle. Mr. Werner is the author of an excellent treatife written in the German language on the external characters of foffils. Mr. Rome has lately publifhed a voluminous treatife on the external forms of cryftals, under which title he comprehends all thofe foffils that are fufceptible of a regular figure, all of which he pretends may be diftinguifhed by the angles which their planes make with each pther, if fome heterogeneous matter be not Contained in them ; but fuppofing all this to f Foyages fas Alps* p. 6 jr. be PREFACE. vii fee true, what a vaft variety of figures are not thefe cryftals fubjeft to from a variety of accidents? How many indeterminate and confided cryftallizations reducible to no cer- tain figure ? By how many external accidents may not thefe figures, though originally per- fect, be altered and modified ? What mall we fay of his macfes or agglutinated cryf- tals ? of the conic, fpheroidal, cilyndrical ftiapes in which no angle can be difcovered ? and of the various amorphous appearances of moft Minerals ? Mr. Werner has endeavoured to claflifjr Minerals by the joint confideration 'of all their external properties, and yet, that even this re-union is inefficient to determine their nature, he hirnfelf gives us a clear proof in his notes onCronfted, p. 217. There, on the faith of thefe charadters, he ranges among micas a green foliated fubftance, which, be- ing fent to Mr. Bergman, proved to be a com- pound of marine fait of copper and argilla- ceous earth, though the quantity fent him amounted but to one grain ; fo much furer £re chymical tefts ! Every icience muft be founded on permanent principles. The only principles of this fort that Mineralogy affords are the relations of the bodies it conliders with chymical agents. Without referring to thefe, it can be reckoned at moil only a con- viii PREFACE, je&ural art. This will plainly appear by ex- amining each of the external characters in particular ; namely, colour, tranfparency, or opacity, coherence, texture, fhape, andfpe- eific gravity. And firft as to colour^ Mr. Werner ownes that white quartz, white lead ore, and white calcareous iron ore, have exaffly the fame fnoiv 'white colour. Some fpecies of the ores of iron, manganefe, cobalt, and copper, the fame iron grey colour, wolfram and blende the fame broivnijh black^ &c. in fhort it is well known, that the flighted change in the texture of bodies, frequently produces a con- fiderable alteration in colour ; thus a lump of cinnabar, whofe colour is dark red, becomes of a beautiful florid red, by fimply reducing it to a powder; befides.it is difficult, if not impoflible, to render the various fhades of colour intelligible by any defcription. Tranfparency and Opacity are qualities com- mon to a vaft variety of fubftances, different in all other refpedls. They are fufceptible of numerous undifcribable degrees, and difcover at moft the mode of union, not the fubftan- ces united. I V, Coherence andhardnefs are properties equally ambiguous : with refpeft to earths and pow*- deredi PREFACE. ix <3ered ftones, their confideration is of no life, ftriking fire with fteel, has often been given as a teftof pufe filiceous earths, but it is now known, that well baked clay, to fay nothing of other compound fubftances, will exhibit the fame appearance. Texture^ all its varieties as granular, la- mellar, fibrous, fcaly, equable, &c. are com- mon to fubftances, widely different ; thus the fibrous is found in fome varieties of gypfum, in afbeftos, fhoerl, pumice, pyrites, antimony, haematites, malachite, cobalt, and arfenicai ores, the fcaly in lead and iron ores, mica, limeftones, gypfum, the lamellar, granular, and equable, are ftill ofWider extent. Shape, the varieties of this even when re- gular and determinate, are endlefs, as may be feen in Mr. De Lijle's Treatife, and muft be fo, as they depend of various external acci- dents, thus he finds 32 varieties in the fhape of calcareous fpar, 14 in that of gypfum, 9 in that of fluor, 1 6 in that of quartz, befides its monftrous forms, equally regular as the reft, 19 in that of felt fpar, &c. and not only the fame fpecific fubftance is fufceptible of various fhapes, but various fubftances fpecifically dif- ferent, affume the fame fhape. Thus the native calx of arfenic, blende, cinnabar, and grey copper ore> often appear in a tetrahaedral form ; x P R E F A C E. form ; common fait, fluor, zeolyte, galena, in a cubic, &c. if the nature of any fubftance could be determined by its form, it would undoubtedly be that of falts, yet there is fcarce any of thefe which in different circum- fiances, may not affume a different figure ; Mr. Pot't affures us, that microcofmic fait aflumes the figure of almoft all other falts, nitre, vitriol, falammoniac, allum, glauber's falts, &c. 4 Pott) 49. According to Ma- quer, if fublimate corrofive be cryftalized, by cooling it forms needles, but if by mere eva^- poration, cubes or lozenges. Mem. Par. 1755* p. 540. Digeftive fait will form cubes if it be exactly neutral, but if the alkali predo- minates quadrangular prifms, common fait is generally looked upon as the moft con- ftant in its figure, yet Mr. Cadet has found it cryftalized in needles, 9 Mem. bcav. Etrang. p. 555. and Gerhard^ 4 Berlin^ Schrift. 292, Very many, if not moft of the miftakes to be found in chymical writers on falts, arofe from their having denominated them from their figure. Laftly, Specific Gravity.) which is certainly one of the beft external tefts, frequently va- ries, by reafcn either of the different texture of the fame fpc.cies of mineral, into whofe jnterftices water cannot equally penetrate, or by reafon of the greater proportion of fome or P R E F A C E. xi or other of the conftituent parts, as is parti- cularly obfervable in zeolytes, which differ exceedingly in the proportion of water which enters into them as one of their conftituent principles: alfo in the fparry or calcareous iron ore, whofe proportion of calcareous earth is fubjeft to great variation ; befides all this, various fubftances fpecifically different* poffefs very nearly the fame fpecific gravity. Neverthelefs I am far from afferting, that the confideration of mere external properties is intirely ufelefs ; on the contrary, I am per- fuaded that from the confideration of thefe alone, a very probable conje&ure may be drawn in moft cafes concerning the nature of foffils, whofe fpecific properties are already known by analyfis, but this conje&ure muft be formed by an experienced eye : for it is not poffible by any defcription, to convey an adequate idea of thofe minute differences, or as I may fay, the phyfiognomies of foffils, by which alone they are diftinguifhable. On this account 1 have been very fuccinft in this par- ticular, rather hoping to help, than expelling to form the coup (fceil. Thofe who love to amufe themfelves with a detailed defcription of thefe external forms, may confult with ad- vantage Mr. Rome de Lijle's improved edition of his Cryftallographie *, though $aily expe- * Or the improved edition of Cronfe^ which Mr. Magel* Ian promifes foou to publifh. rience kii PREFACE. rience evinces, that nature is ftill more varied than his descriptions.* But where any new fubftance occurs, or an intire certainty re- quired, fuchas conftitutes the foundation of a Jcience, there chymical tefts are abfolutely re- quifite, and alone fufficient. Thus negle&ing thefe, Mr. Rome de Lljle took that to be a zeolyte which Mr* P die tier afterwards found to be an ore of zinc. 2 Cryjlallogr. p. 46, 2O Roz. 424. Mineralogy mufl therefore, on the whole, be confidered as a branch of Chymiftry, and its progrefs, like that of other branches of that fcience, has been for many ages fcarce fenfible. In the earlieft times, of which we have any account in hiftory, mankind feern to have been of the fame turn of thinking as the lefs enlightened and civilized nations of our own age. Satisfied with fuch informa- tion as cafual experience threw in their way, they regarded the occupation of confulting na- ture by experiment as a childim, trifling and ufelefs amufement, and neglected forming any theory whatfoever concerning its opera- tions ; but in fucceeding times the gene- ralizing fpirit of Ariftotelic Metaphyfics ex- tending itfelf to Natural Philofophy, foon fuggefted the notion of one common matter * See Ron. journal for March, 1784^,206, 207, and 211. being PREFACE. xiii being \hzfubftratum of all vegetable, animal and mineral fubftance^, difcriminated only by particular forms, which in the two former were held to be fubftantial, and in the latter purely accidental. From this ungrounded opinion (to which however fome of the greateft men in the laft century were much attached) that of the tranfmutability of me- tals into each other naturally arofe ; and to this notion, and fome other equally f alfe, the progrefs of Mineralogy, and every branch of Chymiftry, is undoubtedly owing. To ac- complifh their favourite purpofe experiments were multiplied without end, and by means of thefe the arts of dying, pottery, glafs- making and metallurgy were infenfibly im- proved. The two laft named arts neceflarily re- quired fome knowledge of the chymical pro- perties of ftones and earths. Accordingly we find that all thofe that were ufeful in the former were called vitrifiable -> thofe that were capable of burning to lime calcareous, and thofe on which fire could produce neither ef- fecT:, apyrous. For a long time thefe three divifions were thoyght to comprehend all fpecies of earths and ftones. The fame nar- row fpirit of referring every thing to what is already known, induced Mineralogifts toclafs all metallic fubftances under fome of the fpe- *iv PREFACE. cies antiently known, denominating all thofe which difcovered any fmgular properties m&j* rapacious and arfenical compounds. Hence the oppofition which the introduction of the new femi-metals, cobalt, nickel, and manganefe ftill meets with among Mine- ralogifts of the antient ftamp. However at laft, happily for fcience a few diftingmfhed characters appeared, who, re- jecting all hypothetical delufions, determined, not only to fubmit to no other guide but actual experiment, and its neceflary confe- quences, but alfo to follow it wherever it led them. Of this truly philofophic band, Mr. Margraqf of Berlin led the van, followed by a few others, particularly in Sweden. Dit- coveries now multiplied apace in the hands of a Brandt i Sewab^ Cronfted, Gahn^ and particu- larly Mr. Scbeele, until at laft Mr. Bergman of Upfal, by the folidity of his judgment, the ingenuity and accuracy of his methods, and the multiplicity of his experiments, brought Mineralogy to that degree of perfection at which we at prefent behold it. CONTENTS CONTENTS. PART I. C/F EARTHS and STONES P. l CHAP. I. Of Simple Earths, their number and Cba- ratters — — — 3 CHAP. II. Of the Affinities of Earths to each other r I CHAR III. Of the Syflematical Arrangement of Earths and Stones — 1 8 CHAP. IV. Calcareous Genus — — 22 CHAP. V. Barytic Genus — ~ "—53 CHAP. VI. Muriatic Genus — — 58 CHAP. VII. Argillaceous Genus — — 71 CHAP. VIII. Siliceous Genus — — 103 CHAP. IX. Of Vegetable and Animal Earths i j/j. APPENDIX I. Of Diamond and Plumbago — 157 APPENDIX II. Of the general Examination and Analyjis of Earths and Stones *— . 160 a PART II, xvi CONTENTS. PART II. Saline Sub/lances 1 1^ CHAP. I. Of Acids — 1 74 CHAP. II. Of Alkalis — 177 CHAP. III. Of Neutral Salts — 1 80 PART III; Inflammables - — — - 208 PART IV. Metallic Subjiances . — 226 CHAP. I. Gold — — — 230 CHAP. II. P latino. — — — 238 CHAP. HI. Silver — — 240 CHAP. IV. Coffer — 256 CHAP. V. Iron —• — — • 269 CHAP. VI. Tin — — 391 CHAP. VH. Lead — — — 297 CHAP. VIII. Mercury — - — — 306 CHAP. TABLE IIL continued. 405 iob Parts Siliceous Genus. Sikx. Argill Calcar. Magn. Iron. 93 6 I — — 80 18 2 — — J. 72 22 6 — — 75 20 *— . — ' s 84 l6 — — - 39 40 mild 9 — 10* 39 46 ditto 8 — 6 40 dit. 20 — 13 24 60 8 >— 6 35 58 5 •T" 2 67 H z 8 _ _ c 55 39 6 — — 48 3° 12 — 10 27,6 16 «— 19 448 40 5 i 5 rS 27 f i f 61,6 6,6 21,6 5 1,6^ 37 45 13 — 5* 8 2 2f> 47»5 32»5 — 20 47 30 5 — i 18 49 35 4 12 69 22 L - ••"• 9 84 or 90 , f- „ 6 to 15 _ f 5° — — 30 mild 20^ 70 5 mild25 A 70 5 dit. 20 51 62,5 — d?37,5 — — 77 20 — — 5 80 5 ' — — '5' Cryftal Flint Petrofilex Jafper Chalcedonian Ruby Topaz Hyacinth Emerald Sapphire - Chryfoprafium - Lapis lazuli - - Felrfpar - - - Vefuvian garnet - Garnet Martial Garnet Shoerl tranfparent Shoerl Black - - Bar (hoerl Tourmaline Bafaltes Rowley ragg Comp, and cellular lava Vitreous ditto - - • Another from Lipari Black agate of Iceland 1 nearly as the above J Pumice (tone Martial muriatic fpar - Turkey ftone Ragg ftone - - • - Siliceous grit with cal- "I careous cement - J Siliceous ditto with ar- gillaceous cement - Ditto with ferruginous cement ... a 0,6 copper, and fparry acid. b So martial fluor, 20 gypfum, as I believe. c n Ponderous. d 5 water. e At a medium. / Remainder calcareous. g As 1 believe. h As I believe. ; As I believe. k As I believe. / As I believe. 406 Granite . - • Stellften - Granitello . * Rapakivi - Granitone Murkften Norka Porphyry - Pudding ftone Siliceous breccias ABLE III. continued. j* Quartz, felt fpar and mica, ^ Quart?, felt fpar and fhoerl. Quartz and mica.- Felt fpar and mica. I Gfteifs - - Amygdaloides - Metallic rock of Born Variolite Quartz, garnet and mica. [" Jafper, chert, lava, ftioerl containing quartz, felt fpar, ftioerl, mica, or ferpentine in a cryftaline form, f Jafper, chert, filiceous grit, or lava, containing pebbles of an oval form The fame ground and contents, but in angular forms. Quartz, mica, fteatites. Quartz, mica, ferpentine. Quartz, mica, ftioerl, fteatites, or foap rock. ^Quartz, felt fpar, mica, ferpentine. " Jafper, or chert, containing fpar or ferpentine. Quartz, clay and fleatites, and felt fpar fometimes. Serpentine, containingvarious flones. Proportion of Ingredients in Natural Salts. Acids Alka Earth Water Tartar vitriolate 31 63 — 6 Glauber's fait - H 22 — 64 Vitriolic ammon. - 42 40 b— if Epfom 24 19 57 Alum 24 — - 18 58 Vitriol of iron 20 — 55 25 iron. "Ditto of copper - 30 •MM 43 27 copper Ditto of zinc 22 — — . 58 20 zinc. Nitre 3° 63 — . 7 Cubic nitre - Nitrous ammon. "I 46 5° 40 ^^ 21 J4 Nitrous felenite * 33 32 35 Ditto Epfoni - - Salt of Silvius - - 36 30 63 *7 37 7 Common fait - - 33 5° — J7 Sal. ammoniac 52 40 8 Marine felenite - 42 38 20 Borax purified • - 34 I I? 47 Inflammable. Hepatic air — loo cubic inches of it united to water may contain 8 of fulphur. Sulphur— 60 acid and 40 of phlogifton. Proportion of Ingredients in Metallic Ores. 100 Parts. Gold. Ore of Adelfors or Norway — 99,59 martial pyrites 0,41 gold. of Sal/burg in Tyrole — TV~ arfenical pyrites, and, 052 of gold. — of Nagaya — 99 pyrites, galena and filver, 0,83 of gold. Gold fandof Africa — 0,22 at moft. 100 Parts. Si her. Vitreous ore — 25 fulphur, and 75 of filver. Slightly arfenicated at Quad anal- canal — \Q arfenic, and 90 of filver. • fuperarfenicated at ditto—- ditto from 4 to 6 ozs. of filver per quintal. Jfo/ore- — 31 realgar, 8 fulphur, and 60 filver generally. Black ore folid — 40 fulphur, arfenic, and py- rites, and 60 filver. Black (4°8 ) Black ore loofe — 75 fulphur and pyrites, ancf 25 filver at moil. Arfenico-martial ore — from 90 to 99 iron, and arfenic, and from 10 to i of filver. White ore — from 70 to 90 of fulphu rated copper, arfenic, and iron, and from 10 to 30 of filver. Grey ore — from 12 to 24 of copper, from i to 12 of filver, and the remainder ful- phur, arfenic, and a little iron. Brown ore — moftly copper, fulphur, arfenic, a little regulus of antimony and iron, and ' from i to 5 percent, of filver. Plumofe ore — pyrites, arfenic, antimony, and about i per cent, of filver. Cobaltic ore — fulphur, arfenic, cobalt, iron, and from 40 to 50 per cent, of filver. Vitriolic and marine filler — about 70 of filver. i oo Parts. Copper. Red calx of copper — 26 fixed air, i water, 73 copper. Brorwnijh red — pyrites, and from 20 to 50 of copper. Malachite — 29 aerial acid and water, and 71 of copper. Mountain green — 22 aerial acid, 6 water, and 72 of copper. Mountain blue — 29 aerial acid, 2 water, and 69 of copper. Vitreous CONTENTS. xvii CHAP. IX. Zinc — — — 312 CHAP. X. Regulus of Antimony — — 324 O H A P. XI. Regulus of Arfenic — — 327 CHAP. XII. Bifmuth 332 CHAP. XIII. Cobalt — 335 CHAP. XIV. Nickel — — — 341 CHAP. XV. Regulus of Manganefe — — 345 CHAP. XVI. Siderite — — - 354 CHAP. XVII. Molybdena. Molybdena membranacea Cronjl. 154. WaJJerbley of the Germans 357 C H A P. XVIII. Of the Tungflenic Acid 360 CHAP. XIX. Saturnite — — 361 CHAP. XX. Reflexions on the nature of Cobalt, Nickel, and Manganefe 362 APPENDIX HI. Geological Obfervations — 373 TABLE xviii CONTENTS. TABLE I. The Quantity of Metal in a Reguline State af- forded by IQO Grains, &c. — 398 TABLE II. Of the Weight and Colour of Metallic and Earthy Precipitates, &c. — 399 T.A B L E III. Of the Proportion of Ingredients in Earths and Stones 403 CORRECTIONS. P. Line 12. 14. Dele they 16. 10. Dele and 34. for Species III. read Species IV. and correct the numerals of the other Species, as far as p. 46, where for Species XI. read Species XII. 36. i. read if Iron be precipitated from the fparry acid by lime water, the precipitate will be white, &c, 36. 21. read commonly cubic, fometimes octagonal, or polygonal. _§!• 6. for proceeds the Ihiftus, read proceeds from the ftu'ittis. 75. 21. for 60 of, read 60 per cent of, j 1 8. 6. for parallelipedal, read parallelopipedal. 1 20. 18. for paralleiipeds, read parallelepipeds. 147. 4. for rneln/u read carnelian. 153. 14. for Metallic ftone, read Metallic rock 200. 9. /wfelentine, nWfelenite. 384. 20. for 1000, read IOCOQ. ADDITIONS. 114. 3. Mr. Greville polieflcs an agate, fpeckled with yellow pyrites, which is c^'l^u an Avanturine. 139. 17. Mr. Dolomieu has lately discovered at Strombolly another fort of pumice, which feems to be a ferruginous granite altered by fire. ELEMENTS ELEMENTS O F MINERALOGY. MINERALS in their ftriaeft fignification denote only fuch fabftances as are found in mines, fuch as Metals, Semi- metals, Sulphur and Salts; but in a more extenfive fenfe, they denote all foffils that do not belong either to the vegetable or animal kingdoms, and confequently Stones and Earths, all of which are comprehended under the Denomi- nation of the Mineral kingdom. The mineral kingdom is therefore ufually divided into four parts or clafles, «y/z. I. Earths^ and Stones. II. Salts. III. Inflam- mable Subftances. IV. Metallic Subflances: which naturally point out a fimilar fourfold divifion of this treatife. B PART 2 Elements of Mineralogy* PART I. Of EARTHS and STONES. By Earths are commonly underftood tafte- lefs* inodorous, dry, brittle, uninflammable fubftances, whofe fpecific gravity does not exceed 4,5. which are incapable of being metal ized, are fcarcely foluble in water, and give no tinge to Borax when melted with it. However Quicklime is ufually called an Earth, though it has a pungent tafte and is very perceptibly foluble in water, fo alfo are limeftone and gypfum, though they both contain a purely faline principle, and there- fore in my opinion they and fome other fuch fuhftances may be claffed both among Salts and among Earths. Nay it appears that all Earths are foluble in fome very large pro- portion of water. Hence I think with Mr. Bergman, that in the ftri&eft fenfe the term Earth, fhould, exclufively of any other deno- mination, be appropriated to fubftances of the above defcription, that require above one thoufand times their weight of boiling water to diffolve them, and that thofe which are foluble in between four hundred and one t&oufand times their weight of water may foe called either falts as technical, or Earths as common language requires. Stonn Simple Earths. 3 Stones differ from Earths only in hard- fiefs and its confequences, and therefore are included under the fame generical name. Yet diamond is alfo called a Stone, though it probably contains little Earth of any kind. CHAP. I. Of Simple Earths, their number and Char alters. By fimple Earths, I mean thofe which pof- feffing permanently diftind: Characters, are ihcapableof being further analyzed or changed into any other, by any means hitherto known. Of thefe, we know only five. The Calca- reous, the Ponderous, the Magnejlan or Mu~ riatic, the Argillaceous^ and the Siliceous. All Stones and Earths hitherto examined, are fdund to confift of thefe either iingly, or mixed, orchymically united wjth each other, * in various proportions, together with faline, inflammable and metallic Jubilances ; for in the Earth they are feldom or ever found per* feclly pure. Of the Characters of Calcareous Earth. ift* When perfectly pure and free from all combination, it conftitutes lime ; its fpecific gravity is about 2,3. it has a hot burning tafte, acts powerfully on animal fubftances, B 2 and 4 Elements of Mineralogy. and when in lumps, heats with a moderate quantity of water. 2a- In the temperature of 60? it requires about fix hundred and eighty times its weight of water to diffolve it ; its tafte is then pun- gent, urinous, yet fweetifh. 3d- It is combinable with all acids, and in particular eafily foluble in the nitrous or marine, but difficultly cryftalizes with them, as it forms deliquefcent falts, and is in great meafure precipitable from them by the vitriolic, to which it preferably unites, forming gypfum or felenite, which is wholly precipitable from them by the affufion of highly rectified fpirits of wine, or moderate evaporation, nitrous felenite eafily parts with its acid, when calcined in open veflels and a red heat; but marine felenite fcarcely. Both felenites have a bitter tafte. 4th* When in vefiels on which it cannot a£i, it is infufible per fe (that is fingly;) in a heat that would melt iron : yet Mr. Parker s glafs feems to have induced a flight beginning of fufion in lime, even when it flood on charcoal, but if mixed with argillaceous, mag- neiian or iiliceous Earths, it will melt in a more moderate heat, and particularly if mixed with two or more of thole Earths. And hence Ponderous Earth. ' 5 hence it is fufible in earthen vefFels, even of porcelain ; it is fcarcely affedted by fixed al- kalis, but eafily melted and without effervef- cence by borax or rnicrocofmic fak, or calces of lead. Ponderous Earth. ift* This may more conveniently be called Barytes9 when pure it is alib in the ftate of lime, which it perfectly refembles in tafte, but it requires nine hundred times its weight of water to diffolve it in the temperature of 60? 2d* It is combinable with acids, but with the nitrous and marine, it forms falts that do not deliquefce, and with the vitriolic, a fait much more difficultly foluble than gyp- fum, it decompofes tartar vitrolate, an effedl which no other Earth can operate. 3d- It is precipitable from the nitrous and marine acids by the Pruffian Alkali, a pro- perty which alfo diflinguiihes it from all other Earths, 4th* In the dry way it ads and is afted upon nearly as calcareous Earth, but it is fomething more fufible by the mineral alkali, Its fpecific gravity exceeds 4,000* B 6 Element of Mineralogy. Magnejia or Muriatic Earth irt* Its fpecific gravity when perfectly pure is about 2,33. 2a* It requires about feven thoufand fix hundred and ninety-two times its weight of water to diffolve it in the common tempera- ture of the air. 3d* It is combinable with acids, and though the vitriolic eafily feparates it from the ni- trous and marine, yet it does not precipitate it, as it does calcareous Earth and barytes, but forms Epfom fait which is bitter and foluble in its own weight of water \ whereas with the former Earths it forms infipid and very difficultly fojuble tompounds. 4th- Expofed to the ftrongeft heat, it will neither burn to lime, nor melt per fe, butlofes much of its weight, partly by evaporation, and partly by the lofs of a certain proportion of water, which it naturally retains. Neither will it vitrify in company with any other fimple Earth, except the calcareous, of which, accord- ing to Mr. Achard ioos" will promote the fu- fion of from twenty-five to fifty of magnefia, it will alfo melt with argillaceous and filiceous Earths together, and much more readily if calcareous Earth be added to them. Like lime Argillaceous Earth. 7, lime it Is brought into fufion by borax or. microcofmic fait, but is fcarcely affe&ed by fixed alkalis, or calces of lead. Argillaceous Earth or Earth of Alum. ift* This may more conveniently be called, Argill, its fpeeific gravity when pure does not exceed 2,000. ^ 2*' It is exceedingly diffufible, but fcarcely more foluble in water than pure magnefia. 3d* It is combinable with acids, and when combined with the nitrous or marine, like magnefia it is feparable, but fcarcely precipitable by the vitriolic acid * with which it forms Alum, which always contains an excefs of acid and has an aftringent tafte ; when com- bined with any of thefe acids, it is not pre- cipitable by the acid of fugar, which diftin- quifhes it from the foregoing Earths, all of which (except the ponderous united to the vitriolic acid) are precipitable from the vitrio- lic, nitrous and marine acids, by that of fugar, though the precipitation is not always appa- rent before the liquors are evaporated, nor at all, if there be an excefs of the mineral acids. * For if concentrated oil of vitriol be dropect into a very fatnrate folution of nitrous or marine Alum, a grey ifh preci- pitate w$l immediately appear. 64 The S Elements of Mineralogy. 4th- The ftrongeft heat barely hardens it, but does not give it the qualities of lime, nor melt it, while fingle, or accompanied only with magnefia or iiliceous Earth ; but mixed with calcareous, it runs into fufion very" readily, and hence Mr. Gerhard has found it fufible in a crucible of chalk, but not in one of clay ; fi^ed alkalis do not pro- mote its fufion, but borax and microcofmic fait diflblve it, the firft with fcarce any, and the latter with a more notable efFervefcence. Calces of lead affecl: it fomething lefs than they do calcareous Earths. Siliceous Earth. ift* This is by fome called cryflaline^ quartzy, or verifiable Earth, as it is that of which glafs is ufually formed ; its fpecific gravity is 2,65, and confequently it is the heavieft of all the fimple Earths, except the barytes. It feems lefs foluble irj water than any yet in the common temperature of the atmofphere ten thoufand parts of water may contain one of this Earth ; and in very high degrees of heat, much exceeding that at; which water ufually boiL-., it feems foluble in a much greater proportion? 3d' It Siliceous Earth, 9 3d- It combines with no acid hitherto known, except the fparry, which either in a liquid or Aerial ftate, but particularly in the latter, is ca- pable of holding much of it in folution, which it depofits either on cooling or coming in contaft with water, or fubftances with which it has a greater affinity. But cauftic fixed alkalis may even in the liquid way take up from TV to -^ of their weight of this Earth according as it is more or lefs fubtilly divi- jded, and hence it is not improbable that even lime-water has fome adtion on it. 4th- It is infufible^r/? in the ftrongeft heat, neither does argillaceous or magnefian Earths promote its fufion, the effeft of calcareous Earth is fomewrhat more doubtful, for Mr* Achard * and Mr. Schcffer^ aflert that thefe Earths do not melt together, but Mr. Darcet^ and alfo Mr. Bergman^ and Mr. Swab, \\ fay that two parts lime melt one of quartz ; at leaft there is no doubt but this may be effected in veffels of clay, for an admixture of this will make the other two Earths immediately yield. Fixed alkalis, particularly the mineral, readily melt double their weight of this Earth with effervefcence, borax affects it more dif- ficultly, and with fcarce any effervefcence, and microcofmip fait has hardly any aftion * Mem. Berlin, 1780, p. 32. f Foreles. § 174, b< ; 22 Koz. p. 27. § ScheiT. Foreles, § 175, b, 2 Anmerk. |) 2 Memoires d'LJpfal, p. 443, on lo Elements of Mineralogy, on it > calces of lead acl: on it more power-* fully than on argill, but lefs than on calca- reous Earth, and melt from y to 7 their weight of it. The calcareous, ponderous magnefian and argillaceous Earths being combinable with all acids, may be called abforbent Earths, in contradiftindtion to the filiceous> which unites only to the fparry acid. Befides the general characters of thefe Earths, here given, Mr. Bergman has obferved and noted their different powers of abforbing and retaining water; after moiftening equal weights of filiceous land, chalk, magne- fia, and Earth of alum, with as much water as they could take up without dropping, he found that the fand took % of its weight, chalk I, magnefia i~> and Earth of alum 2,1, and when all thefe moiftened Earths were expofed to the fame heat, the fand loft its water firft, then the chalk, then the magnefia, but the argill, not until red-* hot. Again one of the characters of argillaceous Earth is the extreme fubtility and finenefs of its integrant parts, which render it fmooth to the touch, and (lowly feparable from water when diffuied through it, alfo a certain vifci- dity Affinities of Earths. 1 i dity and duftility which proceed from its power of retaining water, and of thefe pro- perties magnefia alfo participates though in a lefler degree. Siliceous Earths on the contrary are charaaerifed by roughnefs, hardnefs, lharpnefs to the touch, and a total want of flexibility and adherence to each other, when minutely divided, and a ready reparation from water; of thefe properties calcareous and ponderous Earths participate, though in a leffer degree, CHAP II. Of the Affinities of Earths to each other. The above mentioned Earths are never found in nature perfectly pure, but always combined or mixed either with a faline or in- flammable principle, or with each other, oj: with fome metallic principle, particularly iron, be- fides water; when mixed with any notable pro- portion of the inflammable or metallic princi- ples, or even of the faline, fo as to exhibit the characters of fuch principles, they fhall be treated of under thofe particular heads j I fhall here confider only fuch compounds as retain the general characters of Earths, and as in conformity with Mr. Cronjted^ I intend deducing the various fpecies. of Earths from their union either with faline principles or with each other, it will be neceflary to indi- cate the affinities on which fuch unions are founded; 12 Elements of Mineralogy. founded; the affinities of Earths to acids are generally known, but thofe of Earths to each other and to calces of iron have no where been treated of; and therefore require fome developement.— The efforts of art can fcarcely exhibit in the humid way, the affini- ties of Earths to each other, if this could be effected, we mould probably find the fame election and preference take place among them as among Earths and acids, we are therefore obliged to have recourfe to the dry way, which is much more imperfect: foras they are all reduced by fire to a ftate of liquidity, they differ but little in fpecific gravity, and can difficultly be examined while in fufion, when cold they are all found fo mixed that it is not poffible to judge of their affinities by the way of preference and exclufion ; but if we judge of thefe affinities as we do of that of water to falts, by the greater or the leffer quantity which one of them confidered as a jnenftruum, can take up of another or what proportion of the one deter mines the fufron of another, we may in that manner form a tole- rably accurate idea of their different attrac- tive powers. Among the fimple Earths, the calcareous alone,* can be looked upon as the menftru- * Perhaps the ponderous may alfo have th*is property, but it being fcarce, no experiments have yet been made with a view to determine this point. urn Affinities of 'Earths. 1 3 XHII of other Earths, for according to the important difcovery of Mr. I? Arcet, they are all rendered fufible by a proper propor- tion of this Earth, though infufible of them- felves. A difcovery which throws the greateft light, not only on mineralogy, but alfo on metallurgy and the arts of vitrifa&ion and> pottery ; now calcareous Earth requires for its fufion half its weight of magnefia, and only \ of its weight of argillaceous Earth, accord- ing to the experiments of Mr. Achard.^ He did not indeed obferve that it had any effe£t on filiceous Earth, but this appears to be owing to his having ufed too fmall a propor- tion of the calcareous, for Mr. Gerhard^. having expofed filiceous Earth to a violent heat in a crucible of chalk, found it vitrified in the edges where it touched the chalk, but we may infer that this Earth is lefs a&ed upon and more difficultly than the foregoing; even in * the liquid way, calcareous Earth in fome cafes manifefts the fame affinities, thus if Earth of alum perfectly pure be added to lime water, it will precipitate the lime as Mr. Scheele has fhewn in the Memoirs of Stockholm, for 1776, and the precipitate is foluble in the marine acid, which fhews that the precipitation does not arife from any re- mains of the vitriolic acid in the Earth of f Mem, Berlin, 1780. J 2 Gefch. Mineral Reich. alum. 14 Elements of Mineralogy. alum, as gypfum in that cafe would be formed* which is infoluble in the marine acid, but pure magnefia, that is, free from aerial acid* does not precipitate lime water. Siliceous Earth feems alfo to have fome affinity to the argillaceous, for although it cannot be brought into fufion by the argilla-^ ceous, yet when melted by fixed alkalis it a£ts on the argillaceous Earth of the cruci- bles and diflblves it; now fixed alkalis fmgly, cannot melt argillaceous Earth ; to fay no- thing of the hardening power of argill and filiceous Earths, when mixed together and heated. Iron in a more or lefs dephlogifticated ftate* being found in fome proportion mixed or united with almoft all forts of Earths and Stones, de- ferves alfo to have its affinities to tkem men- tioned, it is much more fufible thaix any of them, and may therefore be confidered as a menftruum. Mr* diehard has found that an hundred parts of calx of iron are capable of melting foiir hundred of calcareous, fifty of argillaceous, thirty- three of filiceous and twenty-five of magnefian Earths, it acts ftill more powerfully on lefler proportions of thefc Earths. Hence, Affinities of Earths: 15 Heoce the affinities of thefe Earths, and calces of iron to each other, feem to me to Hand in the following order. Lime) Magncficty j4rg\llf Sihxt . Calx of Ira:* Calr of Iron, Lime, Calx of Iron, Calx of Iron, Lime, Argill, Calx of Iron, Lime, Lime, ArgiH, Magnet, Silex, Argil, Silex, Silex, Magnefia. When fubftances are diffolved and at liberty, their affinities whether in the moift or dry way, are exactly the fame, they being equally divided ; and the only difference is, that in one cafe, they are diflblved by lire, in the other by a liquid. We may alfo obferve, ift, that the lefs calces of iron are dephlogifticated, the greater is their power of attracting Earths as Mr. Rinman has difcovered, and when dephlogifticated to a certain degree, they lofe this power, their colour according to the degree of their dephlogiftication is as follows, whitifh, pale yellow, yellow, ted, brown, green, and blue. adly. That when once lime or calces of iron have a£ted as menftru- urns upon any Earth, a compound menftruum arifes, which ads much more powerfully on other Earths; thus, though one hundred parts of lime can diflblve or liquify very little of filex, yet when thefe hundred parts of lime have taken up fifty of magnefia, they are enabled to diijblve one hundred of filex, and this 16 Elements of Mineralogy. this laft compound forms a menftruum ftill more compound, which is able to diflblve ftillmore of magnefia, for equal parts lime, magnefia, and filex form a perfect glafsj and hence equal parts of any three of the iimple Earths will vitrify in a fufficient heat* fo that calcareous Earth be one of the three ; nay one part lime and one of argill will melt 2 or 2! of iilex, and other mixtures are more or lefs fufible as they approach to this pro- portion. The principal marks of Chymical Union are the following. ift* Afpeclfic gravity exceeding that of the heavieft of the ingredients of the compound, or even greater than the intermediate. But it does not follow that, where fuch denfity is tvanting, a chymical union does not exift, for the peculiar ilructure of the compound which does not admit water into its vacuities may hinder this property from being obferved, fo may alfo a certain quantity of water which enters into the compofition, and cannot al- ways be made fenfible. 2d* Transparency^ when this property is found in combinations of Earths with each other, or with faline fubftances, it indicates a chymical union ; but fuch an union is alfo confiftent Affinities of Earths. 17 fconfiftent with opacity, as this may arife from a mere mechanical arrangement of the parts, or the interpofnion of fome that are not chymically combined, too great thicknefs* &c. 3d- Cryftdlization. This proves that the parts of the chryftalized fubftances have been at fome period very minutely divided ; and in general that they have been chymical- ly combined with the menftruum, in which they chryftallized ; though I agree with Mr. Bergman that a chymical union with fuch a menftruum is not always requiiite; but it does not prove that they were chymically combined with any other fubftanee which chryftallizes with them, except fome other mark of fuch union appears, and particularly a denfny greater than could be expected from the proportion and denfity of the component parts. 4th- A more difficult Solubility in their com- mon menftruums, and of courfe a ftill greater difficulty of folution in menftruums, that acT: only on one of the component parts. Of this there are numberlefs indances, yet there is one exception, viz. where one of the com- ponent parts is reiblvable by the action of the menftruum into an elaftic fluid, which by its eruption fo powerfully agitates and G divides 1 8 Elements of Mineralogy. divides the compound, as to render it more foluble. Thus lime-ftone, and mild mag- nefia, are more eafily diflblved than either lime or calcined raagnefia. On the other hand, fome metallic calces are more eafily diflblved in certain acids, than they are when furnifhed with phlogifton, though this alfo be refolvable into an elaftic fluid ; but this I have elfewhere explained. The calces of iron are fo much the more difficultly diflblved, as they are more dephlogifticated ; hence the whitifli calx is moft difficultly diflblved; and next to that the yellowifh and red ; but the brown, green, and blue, moft eafily ; and hence, ftones which contain dephlogifticated calces of iron and unareated Earths, are moft diffi- cultly diflblved, though the calces are not fo ftrongly attracted by the Earths, nor confe- quently the ftones fo hard, as thofe that con- tain iron in a more phlogifticated ftate. This accounts for the difficult folubility of talc, mica, &c. CHAP. III. Of the Syjlematical Arrangement of Earths and Stones. All Earths may be divided into fimple and compound. Simple are the five unalterable kinds already defcribed, which conftitute five forts or genera* under which all terrene coni- pounds may be ranged. By Earths and Stones a 1 9 By Compound Earths, I underftand thofe that are combined or mixed in a notable pro- portion* either with each other, or with a faline, inflammable, or metallic principle, yet not in fufficient proportion to require them to be arranged under fuch foreign prin- ciples. Such compounds being permanent, and being the foundation of a peculiar deno- mination, I call Jpeeiesy and fimple fpecies, in order to diftinguifh them from fuper com- pounds, which will prefently be mentioned. Thus gypfum is a compound Earth, confifting of calcareous Earth, and a faline principle, not accidentally, but permanently mixed with it. So alfo tourmaline is a compound Earth, confifting of the argillaceous, filiceous, and calcareous, and iron, in proportions deter- mined within certain limits, and forms a fimple fpecies. I faid a notable proportion, becaufe it is difficult to affign this proportion with precifion ; for it relates to denomina- tions of fubftancps, and thefe are founded on the neceffity of diftindlion, arifing fometimes from the ufefulnefs of fubftances to mankind, and fometimes from caprice. Thus, a com- pound Earth, which fhould confift of calca- reous Earth, and only two per cent, of gold or filver, would be denominated an ore, whereas, if it contained only two per cent, of iron, or of another Earth, it would ftill retain the name of, and be reckoned among, calcareous Earths. However, in general we C 2 may 2O Elements of Mineralogy. may fay, that any proportion which produces peculiar effects, or is the foundation of fome particular ufe, is notable. When iron is found in any Earth or Stone, in the proportion of 14 or 15 per cent, it commonly renders it magnetic, either before or after torrefaction, according to its ftate of phlogiftication ; and if it be found in the proportion of 30 per cent, or more, it gives the compound the de- nomination of an ore. To ftones that con- tain a greater quantity of iron than is effen- tial to th^m in the pureft ftate, I add the de- nomination martial, or ferruginous. When fmiple Earths, belonging to different genera^ are mixed or combined with each other, I generally place them under that genus of which the compound contains the largeft proportion, yet not always, for if the compound poffefles the peculiar characters of the component part, which is in a fmaller proportion ; or if it attracts the attention, and is fubiervient to the ufes of mankind, merely on account of the lefs copious ingre- dient, I range it under the genus of that in- gredient. Thus, though common clay contains much more of filiceous than of mere argillace- ous Earth, yet, as it pofieffes fmoothneis, vitci- dity, and foftnefs, in a high degree, it would appear ridiculous to place it under the filice- ous genus, whofe characters are the very re- verfe. For the fame reatbn, I place the ' precious Earths and Stones. 2 1 precious {tones under the filiceous genus, though the argillaceous be, in point of pro- portion, predominant in their compofition. By fuper- compound Earths or Stones, I mean aggregates of vifibfy different fimple fpecies, in a notabls proportion, whether thefe fpecies belong to the fame, or to different genera. Thus I would call a compound of gypfum and fluor fpar a fuper-compound, though both belong to the calcareous genus * and a fortiori granites and porphyries, which forpi aggregates of fimple fpecies belonging to different genera. Super- compounds, there- fore, form compound fpecies, which may be ranged under that genus which is found in them in greater proportion. In general they may be known by the eye, at leaft when aided by a lens. In ftriclnefs, Earths of different genera, each of which contain the aerial acid, fhould, when mixed with each other, conftitute a compound fpecies, yet, as this acid is eafily expelled, and caufes no great difference in the properties of the compound, and as in facT: abforbent Earths, when combined with no other faline principle, ' are feldom without it, I {hall rank thofe compounds among the fimple fpecies, and fo I {hall quartz and filex, though feldom abfolutely pure, C 3 CHAP. 22 Elements of Mineralogy. CHAP. IV. Calcareous Genus. SPECIES 1. Calcareous Earth^ uncombined 'with any Acid. This ftone is of a grey colour, moderately hard, or rather foft, found near Bath ; it is mixed with calcareous Earth combined with fixed air; and hence it effervefces with acids, but at the fame time it is foluble in water, to which it communicates the tafte of lime \ and if this folution be mixed with fulphur, it diffolves it, and forms a calcareous liver of fulphur, with the affiftance of heat ; whence It is plain that part of the calcareous earth is in an uncombined ftate. See Falconer on JBath Waters, vol. i. p. 156 and 257. When expofed to the air for foine time, it hardens, by attracting a fufficiency of the aerial acid, I have obferved feyeral linie-ftones to have the fame property of hardening fome time affer they have been dug. Mr. Monnet alfo found this Earth in a Joofe, dry, powdery form, of' a yellowifh colour, in the moun- tains of Auvergne, and fufpe&ed it to be of yojcanic origin. Miner ahgie^ p. 515. SPECIES Calcareous Genus. 23 SPECIES II. Combined 'with the Aerial Acid. This fpecies comprehends a great variety of external appearances, the moft remarkable of which are tranfparency and opacity, hence I fhall divide it into two feries, the tranfpa- rent and opake ; all effervefce with acids ; none give fire with fteel ; the chryftalized de- crepitate when heated. SERIES I. Tranfparent Spars. Thefe are of a lamellar texture, and moftly break or fplit into rhomboidal laminae ; and this ftru&ure is generally called fpathofe, or fparry. They are found cryftallized in va- rious forms, rhomboidal, hexangular, trian- gular, polyangular ; but the moft common is the rhomboidal, of which fort is the Iceland cryftal, which poflefles a double refracting power. Their fpecific gravity is generally about 2,700, when pure from metallic particles; and they generally contain from 34 to 36 per cent, of the aerial acid, from 53 to 55 of mere £arth, and the remainder water. C 4 Thefe 24 Elements of Mineralogy. Thefe fpars when pure are always colour- lefs, but fometimes they are found green, brown, reddifh, yellowifh, and even black^ from a mixture of metallic particles. De la Hire and Huygens, denote fhom,- boidal fpar under the name of talc. SERIES II. Under this feries I range a variety of ftones. of the fame fpecies, but which are known under various denominations arrifmg from, external properties, or the apparent mode of their origination -, fuch as opake-fpars, ftalacltites, tophufes, incruftations, petrifacr tions, agaric -mineral, chalk, limeftone, Opake Spars. Thefe are chryftalize4 under the lame re- gular forms as the tranfparent fpars, and fometimes appear in a globular form ; their texture is alfo lamellar, they are of different colours like the foregoing; the red frer quently receive that tinge from manganefe. 16 Roz. 15, Stalactites* Calcareous Genus. Stalactites^ Sinter Calcareum^ Stma, Thefe are found fufpended from vaults, being formed by the oozing of water charged with calcareous particles, and gradually eva- porating, leaving thofe particles behind; this depofition can fcarce be called a chryftaliza- tion, as the calcareous particles do not ap- pear to have been diffolved, nor even very minutely divided, though this fometimes happens, whereas tranfparent fpars appear to have been formed from a folution in water, by means of the aerial acid. Stalactites are of a lamellar or granular texture, and either in a branchy form, or in that of perforated cones, or globular, and then called Jlalag- mites, oolitheS) pifolites, &c. Moft of thefe ftones contain a flight mixture of argill and calx of iron. And hence are of a grey, brown, yellow, or blackifh colour. Tophi, Duckftein of the Germans, Port. Thefe differ from the former, not only in fhape, but principally in this, that they have been formed by a gradual depofition of Earths, chiefly of the calcareous kind, barely diffufed through water, within the water itfelf and not in air. Hence they are of a foft and porous texture, and of the fame colour 26 Elements of Mineralogy. colour as the foregoing, the pureft forts alone are placed here. Calcareous Incrujlations* Thefe are generally found on branches or roots of trees, and fometimes on ftones of different kinds, the moft remarkable of thefe incruftations is that found on the roots of pines, called Qfteocolla^ which Mr. Margraaf found to confift chiefly of calcareous Earth, mixed with a fmall proportion of filiceous, and volatile alkali, together with fome vege- table parts* Calcareous Petrifactions. Thefe confift of calcareous ftones, in the form of animal or vegetable fubftances, the former are called Zoophytes^ the latter Phy-> tholites. The moft remarkable of the former are, ift, Thofeof the Cbr^/clafs, of a ramified and tubu- lar form as coral, madrepores, millepores, aftroites, 2d, Thofe of the clafs of fea worms, belemnites, which are of a conic or cylyndrical form. Afleritz and Entroctfo which have a ftarry appearance. 3d, Thofe of the tefta- ceous clafs, as nautllitcs^ ammonites ^ echini y Agaric Calcareous Genus. 27 Agaric Mineral, Guhr. This fanciful name denotes only a loofe Calcareous Earth found in the clefts or cavi- ties of rocks, moftly white, but fometimes red or yellow, from a mixture of clay or ochre. Chalk, Craie, fyaie de Champagne^ blanc d Efpagne of the French. This fubftance is too well known to need any defcription, the pureft is iv&tte, yet it contains a little filiceous Earth, and about two per cent, of argill. Mr. Rinmaris Hiftory of Iron, § 201, mentions a blue chalk found in the ' neighbourhood of Upfal, which con- tains iron. Mr. Beaume fays that the pureft calcareous Earths he has met with contain fome fmall proportion of iron, which depofits from fokitions long made, i Beaume 255. however I have frequently ufed chalk, in whofe folution neither galls nor Pruffian alkali could difcover any. Dry chalk contains more aerial acid than any other of the cal- careous clafs ; generally about forty per cent, jts fpecific gravity is from 2,4, to 2,65. LimeftoneS) f a 8 Elements of Mineralogy, Limejlones, Albarefe of the Italians. All ftones which are ufually burned to lime, are comprehended under this name ; fome are of a lamellar and fome of a gra- nular texture ; their colours are various, the pureft are white, grey, or bluifh grey, their proportion of aerial acid is fomething greater than that in fpars, and all contain fome fmall proportion of argill, quartz and iron. 18 Roz. 345, Mr. Meyer afferts, that in the pureft limeftones he has examined, thefe foreign ingredients amounted to about four per cent, he alfo fays that he has found marine Epfom and fea fait in fome fmall proportion in all of them, i Meyer^ 5,20, and 21. Some limeftones found in Scania, contain orpiment according to Scheffer* account. Among limeftones we may reckon, that called St. Stephen's ftone by Cartheufer and Vogel^ becaufe it has fome red fpots on its furface refembling blood ; the lamellar limeftones ufually contain petrifactions, chiefly of marine animals and alfo {hells ; the fpe- cific gravity of limeftones is from 2,65, to 2,70, generally. Ketton Stone is a remarkable fpecies of limeftone, confifting of very fmall globules like the roe of fifti, concreted together, Jlence Calcareous Genus. 29 Hence its fpecific gravity is only 2,456, and it is called Hammite^ it contains ninety per cent, of mild calcareous Earth, and ten per cent, of argillaceous Earth fo firmly united to red calx of iron, as to be difficultly foluble even in aqua regia ; the proportion of iron is not above one per cent, in this ftone, and yet it feniibly colours it. Portland Stone, and Purbeck Stone belong alfo to this clafs, the fpecific gravity of the former is 2,533, an^ °f tne latter 2,680, according to the experiments of Dr. Watfony who accordingly found that the latter afforded more lime, 2 Watjoris Eflfays, 190. Portland Stone is of a dull white colour, loofe open porous texture, eafily cut, and contains a fmall proportion of filex. Bath Stone refern- bles the Portland, but its texture is more granular and open; its fpecific gravity 2,494. Calcareous Flag-flane^ otherwife called cal- careous fchifttiSv That found near Wtipd- flock, and ufed for covering hcufes, is of a yellowim white colour and moderately hard, its fpecific gravity is 2,585, contains a little clay and more iron than the Portland Stone, Marbles. jo Elements of Mineralogy. Marbles. Opake ftones of any fort, fomething harder than limeftones, more compact, of a clofer grain and fufceptible of a good polim, have been called Marble by ftatuaries, but this name is now appropriated to ftones of the above defcription, of the calcareous genus only- The fpecific» gravity of Marbles is from 2,7 to 2,8, their texture like that of lime- ftones is either lamellar or granular and their colours various, not only in different mafles, but in one and the fame piece; thefe laft will be mentioned among the compound fpecies : when the different fpecies are in large diftindt maffes they are called Breccias, Marbles of three colours, grey, yellow, and black; which abound in petrifactions, are called luma- chellis ; thofe of four colours, white, grey, yellow and red, are called Brocatellos. I ihall here only mention the purer forts that contain the leaft mixture of foreign genera. White Marble, particularly that of Carrara^ is the pureft with which we are acquainted; it is of a granular texture and fparkling in its frafture like fugar ; its fpecific gravity is 2,7175, of this fort is the Pietra Elajlica of 'Rome. Ferber, Italy, 130. Other white mar- bles are not fo pure, many are of a lamellar texture. Black. Calcareous Genus. 31 Black. This colour is commonly owing to a flight mixture of Iron. Mr. Bayen found one fpecimen of it to contain five per cent. of iron, yet the lime made of it was at firft white, but in time acquired an ochry* or reddifh yellow colour, 1 1 Roz. 496. Mr. Bergman remarks, that all calcareous ftones which grow black or brown by calci- nation, may be fufpe£fced to contain man- ganefe, in that cafe the lime they form is excellent as a cement. 2 Bergman, 229. And according to Rinman (Hiftory of Iron, § 189,) white calcareous ftones, that grow black by calcination, contain about ten per cent, of iron. Grey. This fort of marble contains left iron, only one or two per cent, according to Mr. Bayen. Blue and Green marbles derive their colour from a mixture of fhorl, according to Mr. Rinnan, H'lftoriaferri. § 201. 206. SPECIES III. Combined 'with the Vitriolic Acid. Gypfum, Seknite, Plaifter of Paris. This fpecies is of different colours, moftly white or grey, of a lamellar, granular, or fibrous $i Element* of Mineralogy. fibrous texture, of a moderate hardnefs, not fo great as to give fire with fteel ; fometimes opake, fometimes pelliicid, fometimes regu- larly chryftalized, and fometimes amorphous. Its fpecific gravity is 2,32 generally, fome- times only 1,87. It is foliible in about five hundred times its weight of water, at the temperature of fixty. It does not effervefce with acids, and is difficultly foluble in any, particularly in the marine. When hedted a little below ignition, it un- dergoes a motion fimilar to that of ebullition, from the diffipation of its aqueous part* and falls into powder ; if taken up when this motion ceafes, and fprinkled over with water^ it foon concretes and hardens, by reafon of its fudden chryflalization. If calcined with J of its weight of char- coal, it yields a liver of fulphur, and the Earth thus feparated, treated with black flux, frequently yields a little of Iron: it is fuiible per fe by the blow pipe. 2 Bergman, 469, or in a long continued porcelain heat, 22 Roz. 26, though Mr. Gerhard fays this does not happen in crucibles of chalk, but only in thofe of clay. 2 Gerh. Gefch. 16. It Calcareous Genus. 33 It contains about 30 per cent* vitriolic acid, 3$ of mere Earth, and 38 of water; of which it parts with about 20 by calcination. The beft method of decompofmg it is to boil it, well pulverized, in a fixed alkaline lye. The varieties of its external appearances may be prefented under two feries, the tranfparent and opake. SERIES I. Iranfpartnt. Lapis Specularts, Vitrum Ruthenicum, Clacks Stirium Pellucidum, Gypfum Spa* thofum Diaphannm. This is either colourlefs, or yellowifh* green, or reddifh ; which laft colour is from iron, as Mr. Morveau has, by means of vinegar, completely feparated it. Its form is either amorphous, or regular, generally cubic 5 its texture lamellar, fcaly, or fibrous. SERIES II, Opake. The colour of this is either white, grey, greenilh, or black j its texture D fcaly, 34 Elements of Mineralogy. fcaly, fibrous, or granular ; its fliape either regular as cubic, rhomboidal, or prifmatic, confifting of three or five fides ; or amor- phous, of which fort is alabajhr* whofe tex- ture is granular, with fhining particles, and its fpecific gravity 1,87. SPECIES III. Combined *witb the Sparry Acid. Fluor, Spathumfujibile, Petunfe of Margraafr 2 Tbeil. p. 45, Blue John. Its colours are various, being either white, yellow, blue> green, reddilh, purple, brown, or colourlefs ; its texture fparry or fhattery ; its form either amorphous or regular; its hardnefs not fo great as to give fire with fteel ; its fpecific gravity from 3,14 to 3,18 ; if greater it proceeds from a large propor- tion of metallic or other foreign particles. It is infolublc in water, does not effervefce with acids, and is fcarcely foluble in them without decompofition. When heated it decrepitates and burfts, but does not yield lime, nor harden by the af- fufion of water, as gypfums do. The colour- ed fluors become phofphorefcent when heated flowly, Calcareous Genus. $$ flowly, below ignition, but lofe this property when made red hot, and alfo on cooling. It melts perfe in a ftrong heat, and violently attacks the crucibles, as it powerfully pro- motes the fufion of argillaceous Earths. It is alfo fufible with mineral alkali, borax or mi- crocofmic fait, and without effervefcence. It confifts of the fparry acid, water, and calcareous Earth. According to Mr. U Arcet, the acid is in the proportion of 16 per cent. 22 Roz. 24. and according to Mr. Scheelc, 100 gr. of fluor contain about 57 of mere Earth, and confequently about 27 of water ; but I^be- lieve it contains much lefs water, and much more acid, for a great deal of the acid pierces through the luting during diftillation. It is decompofed by diftilling it with three times its weight of concentrated vitriolic acid, but to obtain the fparry acid pure, it fhould be diftilled with its own weight of that concentra- ted acid pure and colourlefs, at firftwith a gen- tle, and towards the end with a flrong heat, placing water in the receiver, in the proper-* tion of 10 or 12 times the weight of the fpar. The nitrous and marine acids de- compofe it if dilute, but not when thefe acids are concentrated. Blue fluors derive their colour moftly from iron, but fometimes from cobalt. 2 Berlin* D 2 Befcbaff. 36 Elements of Mineralogy. Eefchaft. 330 ; and in fadt, iron, precipitated from the fparry acid by lime water, is white, with blue fpecks. Green fluors owe alfo their colour to iron. Rinman, § 206. Moft fluors contain a mixture of argilla- ceous and filiceous Earths, and fome marine acid. The filiceous Earth, which fublimes in diflilling thefe fpars, arife, from thefolution of that pre-contained in the fpar, or from .he corroiion of the glafs veflels, as Meflrs. Mayer and Wiegleb have (hewn ; this acid pof- feffing the fmgular property of diffblving filiceous Earths, and confequently glafs. The varieties of this fpecies may be re- duced to two, the tranfparent and opake ; of which there are neceflarily many interme- diate fhades. SERIES I. Tranfparent. Thefe are generally of a regular fhape, cubic, rhomboidal, polygonal, and of diffe- rent colours ; and hence called pfeudo-eme- raids, fapphires, topazes, amethyfts, &c. — Some are amorphous. SERIES IL Calcareous Genus. 37 SERIES II. Opake. i Thefe are diftinguifhed by the fame co- lours ; their texture alfo is generally the fame, but it is faid to be fometimes granular ; their form is alfo regular, or amorphous, like the foregoing. The phofphorefcent property of fluors feems to arife not from the acid fingly, other- wife all fluors would poflefs it, but from the acid, in contadt with metallic particles, and confequently from the acid and phlogifton, SPECIES IV, Combined with the T'ungflen Arid* Tungftetii Lapis Ponderofusy Schiverere Zin- graupen of the Germany. When pure it is of a grey colour and lamel- lar texture, gives fire with fteel, and is very weighty, its fpecific gravity being from 4,99 to 5,8. It is infoluble in acids, except by peculiar management; when powdered and digefted P 3 with . 38 Elements of Mineralogy. with the nitrous or marine, it affumes a yel- low colour, as Mr. Woulfe firft obferved. Phil. Tranf. 1779, p. 26. When heated it burfts, becomes reddifh, jnelts very difficultly per fe ; nay, according to Mr. Bergman^ it is infufible with the blow pipe, and not totally fufible even with the affiftance of fixed alkali, but eafily by borax;, and without effervefcence. It alfo eafily melts with its own weight of fluor, Its conftituent parts were difcovered by Mr. Bergman and Mr. Scheele^ nearly at the fame time, but firft publifhed by Mr. Scheele in the Swediih Memoirs for 178 1. It appears to contain about i its weight of calcareous Earth, and the remainder a peculiar acid of an earthy appearance, and iron. This acid is feparated from its earthy by digefting the powdered ftone in three times its weight of nitrous acid, and after pouring off this acid, and edulcorating the refiduum, digefting it again in cauftic volatile alkali, after fome time the alkali is alfo poured off, and the refiduum being edulcorated, is again digefted in nitrous acid, and afterwards jn volatile alkali : Thefe fucceflive digeftions ^re continued until the greater part of the ftone difappears, t;he nitrous acid conftantly taking Calcareous Genus. 39 taking up the calcareous Earth, and the vola- tile alkali uniting to the tungften acid; at laft the tungften acid is precipitated from the volatile alkali in the form of a white powder, by faturating the alkali with any other acid. This powder is foluble in 20 times its weight of boiling water, and then reddens litmus, has an acid tafte, and with lime water pro- duces a regenerated tungften ; its fpecific gravity is about 3,600. SPECIES V. Mild Calcareous Earth mixed 'with a notable Proportion of Magnefia* I. VARIETY. Compound Spar. This ftone is defcribed by Mr. Woulfe. Phil. Tranf. 1779* p. 29. It is there faid to be either white and femitranfparent, or of a pearl colour, or reddifh, or of different {hades of brown or yellow, of a peculiar glofs or brightnefs, like gold, brafs, or copper ; and to confift of flat, folid, and rhomboidal chryftals, and harder than calcareous fpars, Jt effervefces with acids. One hundred parts of it contain 60 of mild calcareous Earth, 35 of mild muriatic, and D4 5 40 Elements of Mineralogy. 5 of iron: the iron appears to be accidental, and its quantity greater or fmaller, according to the colour of the ftone. II. VARIETY. Creutzenwald Stone. This ftone is mentioned, but not defcribed by Mr. Bayen. 13 Rox. 59. It is probably of a brown, or yellowifh colour, and great weight; it contains by Mr. Bay ens account, 75 per cent, mild calcareous Earth, 1 2 mild magnefia, and 13 of iron. It is found near Creutzenivaldy and there ufed as a flux for iron ores. SPECIES VI. Mild Calcareous Earth mixed *whh a notable Proportion of Clay. I. VARIETY. In a loofe Form. Calcareous Marl. Marl is well known from its life in. Agri- culture. I diftinguifh two forts of it, the calcareous and the argillaceous ; it is of va- • rious colours, grey, yellow, red, brown, or bluifli ; thefe arife from a mixture either of iron or pyrites. The calcareous ftrongly ef- fervefces Calcareous Genus. 41 fervefces with acids ; it is of different de- grees of hardnefs, and readily burfts and falls into powder in water, or by expofure to the air. When the calcareous Earth is in large proportion it burns to lime, and even vitrifies in a ftronger heat. The proportion of mild calcareous Earth is from 50 to 75 or 80 per cent, if greater it ihould rather be clafled among chalks. Hence any Earth of this fort, that lofes from 16 to 27 parts of its weight per cent, by folution in acids, may be deemed a calcareous marl, this being the weight of the volatilized fixed air which correfponds with the above proportion of cal- careous Earth, Note alfo, that by clay I mean common clay, that is, a mixture of argill and filiceous Earth, in which this lat- ter moilly predominates. See Dr. Withering 's Diflertation. Phil. Tranf. 1773, p. z6i,and3. p. 4. II. VARIETY. In a Stony Form. Pietra Forte, Putra Fongaia of the Italians, Margodes. The two firft differ only in hardnefs ; they are of a grey, blue, or yellow colour ; the firft loofe and porous, the fecond harder ; the third is a tufa, which, containing the feeds of mufhrooms, produces them yearly, on being 42 Elements of Mineralogy. fprinkled with water. Ferrer Italy, 117, They are often formed of volcanic afhes, in- durated by water, and evidently contain fome proportion of iron ; the two firft are ufed as lime ftones. The pietra colomblnay and tur- china, are faid to be of this fort. Analogous to thefe is the margodes, a blu- ifh grey ftone, entirely refembling clay in its outward appearance, but fo hard as to cut fpars, or even zeolytes, but not to fuch a degree as to give fire with fteel ; dull in its fracture, its texture thick laminse, and of a conchoidal form; its fpecific gravity 3,877; it effervefces with acids. I found it to con- tain 50 per cent, of calcareous Earth, about 32 of argill, i£ of filex, and 2 of iron. Mr. Bergman^ in his remarks on the mountains of Weft Gothland, Memoirs of Stockholm, 1768, mentions a fort of rtd mar- ble found near Roloock, which contains fo much clay that it hardens in fire, and eveu jnelts in a ftrong heat, SPECIES VII. Mild Calcareous Earth mixed •with a notable Proportion of Ponderous? Earth. Barytical Limejlone, or Marl. This is faid to be found both in a ftony and loofe form in Derby/hire ; the former is faid Calcareous Genus, 43 faid to be of a grey colour, and heavier than common lime-ftones, but I have feen none of them. i SPECIES VIII. Mild Calcareous Earth mixed •with a notable Proportion of Siliceous Earth* I. VARIETY. Stellated Spar, Stern Sfatb, Stern Schoerl of the Germans. This is opake, and of a radiated forms found in limeftone by Mr. Ficbtel on the Carpathian Mountains. It effervefces ,with acids, and according to Mr. Bindheim^ JQO parts of it contain 66 mild calcareous Earth, 30 of filiceous, and 3 of iron. 3 Scbrift. Naturforfcb. Freunde, p^ 454. II, VARIETY. Calcareous Grit, Calcareous Sand-Jlone, Calca* rius ArenariuS) Pierre de Taille Calcaire^ Moellon^ Pierre de Liais. Monnet Mine* ralogie, p. 216; Its colour is various, but moftly white, grey, brown, or of different (hades of yel- low : it effervefces with acids, and is more or lefs foluble in them, according to the pro- portioa 44 Elements of Mineralogy, portion of mild calcareous Earth, which alfa varies, from 50 to 70 or 8^ per cent, when lefs, it ihould be reckoned among the (iliceous fand-ftones. It frequently contains alfo a fmall propor- tion of argill, and a ftill fmall er of iron. Its furface is generally rough ; its texture moftly granular, but fometimes fcaly : it does not ftrike fire with tteel ; it is fometimes ufed as a limeftone; it hardens by expofure to the air ; it is frequently fprinkled over with mica, but not in fuch proportion as to alter its genus or fpecies. The fand-ftone of St. Helena^ which is very brittle, and burns to lirne, is of this fpecies, SPECIES IX. Mild Calcareous Earth mixed Pierre de Sf. Ambrolx. This ftone was analyfed by Baron Servieres^ 21 Roz. 394. 22 Roz. 207. Its colour is iron grey, interfperfed with fhining particles. Its texture compact 5 its hardnefs fuch as fcarcely to give fire with fteel 5 its fpecific gravity 2,7034. It is foluble in acids, and moflly with effer- vefcence. It 46 Elements of Mineralogy. It calcines in a ftrong heat, and makes nitre flightly detonnate. If diftilled, it af- fords a fmall portion of vitriolic acid, and fome fulphur fublimes. It confifts of about 75 per cent, mild cal- careous Earth, and 25 of pyrites, which con- tains 14 of argill, 7 of quartz and fulphur, and 4 of iron. SPECIES XI. Mixed •with a notable Proportion of Iron. I. VARIETY. Mild Calcareous Earth mixed with Iron. Thefe ftones are either yellowifh white, or red : the former are of a fcaly texture, and grow black when expofed to the air, very weighty, effervefce with acids, and contain about 25 per cent, of iron ; the latter are of a coarfe grain, flightly effervefce with acids, lofe 30 per cent, by calcination, and contain 10 per cent, of iron. Some ftaladites alfo contain from 20 to 27 per cent of iron. Rinman Mem. Stock. 1 754. Other iron ftones of this fpecies, containing more iron, belong to the calcareous iron ores. II. VARIETY. Calcareous Genus. II. VARIETY. Tungften intimately mixed with Iron. Red or Flefh-coloured Tungften. It does not effervefce with acids, fcaroely gives fire with fteel ; is of a coarfe texture, eaiily pulverized: its fpecific gravity from. 4,9 to 5,8 j becomes magnetic after calcina- tion ; eafily melted with its own weight of fluor ; with great difficulty affords about 30 per cent, of iron. Cronfted. Mem. Stock. 1751. Hence it is never ufed as an iron ore. Compound Species^ in 'which the Calcareous Genus predominates. SPECIES I. Compounds of the different Jimple Species of the Calcareous Genus; Here I place all the different compounds of mild calcareous Earth and gypfum, or fluor, or tungften, &c, which may occur; alfo thofe of gypfum and fluor, gypfum and tUiigften, or fluor and tungften, &c. which may be placed as varieties of ^his compound fpecies. SPECIES II. 4$ Elements of Mineralogy, SPECIES II. Compounds of Calcareous and Barytlcal Species* I have feen yellowifli ftones of this fpecies from Derby/hire^ confifting of lumps of chalk interfperfed with nodules of barofele- nite : many more may occur, as compounds of gypfum and barofelenite, fluor and baro- felcnite, &c. SPECIES III. Compounds of the Calcareous and Muriatic Species* Under this head I range all the compounds of mild calcareous "Earth, or fluor, or gyp- fum, which contain fteatites, ferpentine, talc^ amianthus or afbeftos. Of this fpecies the following varieties have been obferved. I. VARIETY. White Marble interfperfed with Spots of Stea- tites, or Soaprock Kolmord Marble. Cronftedr § 261. This is of a fcaly texture, and the fteatites and foapreck either green or black. II. VARIETY* Calcareous Genus* 49 II. VARIETY. I. Pietra Talchina. This confifts of white fpar, with veins of talc. 2. Verde Antico. A light green marble, with deep green," black, white, and purple fpots ; 100 parts of it contain, according to Mr. JBayen9 62 mild calcareous Earth, 30 of green talc, I of magnefia, and i of femiphlogifticated iron. 12 Rozt 56. SPECIES IV. Compounds of the Calcareous and Argillaceous Species. I. VARIETY. Mild Calcareous Earth and Argillaceous Shiftus. i . Green Campanfrom the Pyrenees. This is a marble of a green colour, and flightly magnetic. According to Mr. Bayen, i oo parts of it contain 65 of mild calcareous Earth, 32 of argillaceous, and 3 of femiphlo- giftic^ited iron, n Roz. 499. Since this E ftone ^0 Elements of Miner akgy. ftone is fomething magnetic, it is plain that the ftiiftus muft contain at leaft i o parts iron ; and alfo, that this iron is not much dephlo- gifticated. Hence alfo, the colour is green, which colour, or blue, is always, when it proceeds from iron, a fign that the iron is not much dephlogifticated ; on the contrary, a red or yellow colour from iron, denotes it to be in a dephlogifticated ftate. 2» Red Cam fan. A red marble, not magnetic ; 100 parts of it contain 82 of mild calcareous Earth, n of argillaceous fhiftus, and 7 of dephlogifticated iron, ii Roz. 501. 3, Yellow figured Marble from Florence. Mr. Bay en found 100 parts of it to con- tain 75 of mild calcareous Earth, 13 or 14 of fhiftus, and 4 or 5 of dephlogifticated iron. 4. Grlotte. A red marble from Autun-, contains 67 of mild calcareous Earth, 26 of reddifh fhiftus, 2 of iron, and i of magnefia, per cent, ac- cording to Mr. Bayen. c. Amandola. Calcareous Genus. 51 5. Amandola. A green honeycomb-like looking marble, containing white fpots : 100 parts of it con- tain 76 of mild calcareous Earth, 20 of fhiftus, 2 of femiphlogifticated iron ; the cellular ap- pearance proceeds the fhiftus. 12 Roz. 56. 6. Clfolinfrom Rome. A green marble, with white zones. It gives fire with fteel, though difficultly; 100 parts of it contain 67,8 of mild calcareous Earth, 25 of quartz, 8 of fhiftus, 0,2 of iron, befides the iron contained in the fhiftus. 22 ROZ. 52, IL VARIETY. Calcareous "Earth and Mica. i, Cipolinfrom Autun. A green marble, confifting of 83 parts mild calcareous Earth, 12 of green mica, and i of iron. 12 Roz. 55. 2. Micaceous Limejlone. This is of a glittering appearance, of va- rious degrees of hardnefs, and effervefces E 2 with 52 Elements of Mineralogy. with acids ; the proportion of mica is various. The macigno of the Italians is of this fpecies. Ferber, 1 16. The yellow fort is called pietra bigia, the blue pietra colombina, or tur china. SPECIES V. Compounds of the Calcareous and Siliceous Species. I. VARIETY. With Quartz. I . Calcareous Quartz and Pnddingjlone. This confifts of lumps of quartz, and fometimes felt fpar, in a calcareous cement. 2. Limejlone •with Veins of Quartz, Saxum Sahlbergenfe. Alfo feveral marbles in Sweden and Siberia, that ftrike fire with fteel. II; VARIETY. With Lava. 1. Calcareous Volcanic Pudding/lone^ Cier china. In this, lumps of fpar and lava are found in a calcareous cement. Ferber Italy, 1 1 5. 2. Marble mixed with Veins of black or green Lava. Ferber Italy> 67. SPECIES VI. Calcareous Genus. 53 SPECIES VI. Compounds of Calcareous Earths 'with Species of two or more Genera. I. VARIETY. Calcareous Porphyry. This confifts of quartz, felt fpar, and mi- ca, in feparate grains, united by a calcareous cement. II. VARIETY. . Limeftone inter fperfed with Shoerl and Mica. CHAP. IV. Barytic Genus. SPECIES I. Ponderous Earth combined •with the Aerial Acid) aerated Barofelenite. Dr. Withering prefented me with a very pure fpecimen of this fpecies from Alfton Moor, in Cumberland. It much refembles alum, but its texture is ftriated : its fpecific gravity is 41331* though when this com- pound is artificial its fpecific gravity is only 3>773, according to Mr. Bergman\ evidently becaufe it contains much water, E3 for 54 Elements of Mineralogy. for loo parts of it contain 65 of pure Earth, 28 of water, and 7 of the aerial acid ; whereas 100 parts of the native contain about 20 of aerial acid and 78 of Earth, a little of the vitriolic barofelenite, and no water. It effervefces with acids. The artificial, when calcined, burns to lime, which, has the properties of pure barofelenite already defcribed ; but the natural will not burn to lime, for it will not part with its fixed air, but rather melts, as Dr. Withering has difcovered. He alfo found that cauftic alkalis precipitate this Earth from the nitrous and marine acids, which happens, as I think, from their taking up the excefs of acid requi-* fite to keep it in folution. SPECIES II. Combined with the 'vitriolic Acid. Barofelenite^ Mar m or Met alii cum, Cronff. 182, Lapis Bvnonievfis, Selenitic t Spar, Gypfum Spathofum^ Spat hum Fnflbile^ Margraf 2, Theile p< 44, Weigel 0 ferv< Mineral^. 65 and 66. Ca£/"/£ with a blow-pipe, yet Mr. D'Arcet found the femi-tranfparent fort fufi- ble in a long continued porcelain heat. 22 Roz. 26; probably becaufe it was placed in an argillaceous veflel : but it is fufible by the help of the mineral alkali, with effervefrence, and alfo with borax and microcofmic fait, ac-» cording to Mr. Bergman. It is often mixed with calcareous Earth. 6 Roz. 222. 13 Roz. Supplement^ p. 408 £4 56 Elements of Mineralogy. Mr* Morveau obferves that it accompanies the ores of moft metals. Mr. MargraafMo frequently found maflfes of it mixed with gypfum. i Margr. 332. \The eafieft method of decompofing it, is that praftifed by Mr. Wolfs and Mr. Wiegleb^ viz. by calcining it in a ftrong red heat for i or 2 hours, with i i or twice its weight of fixed alkali ; the neutral fait and fuperfluous alkali are then wafhed of, and the Jtarth is found combined with fixed air. Mr. Afor- *ueauys method is cheaper. He calcines the ponderous fpar with •£ of its weight of char- coal for i hour, in a crucible, well luted, and a ftrong red heat : he then diflblves the Earth in the acetous acid. The fulphur is thus fe- parated. Mem. Dijon, 1782. Mr.Margraqf decompofed it in the liquid way, by mixing two parts of the ftone with one of fixed al- kali ; then pouring hot water on it, and keep- ing it boiling for iome hours, i Margr. 366. The decompofed part, well edulcorated, is foluble in acids. This fpecies often forms the ftony matter of petrifactions, Mem. Dijon, 1782. i Seme/I. P. 163. According to Mr. Bergman, 100 parts of it contain 84 of Earth, 13 of the moft con- centrated Earytlcal Genus. 57 centrated acid, and 3 of water. 100 parts of artificial barofelenite contain about 33 of vitriolic acid and water, and 67 of Earth. Some fpecies, particularly the red, con- tain i or two gr. of iron per cent. SPECIES III. Combined with the Sparry Acid. This combination has not yet been found in nature ; that formed by art is nearly info* luble in water. SPECIES IV. Combined 'with the Tungften Acid. This combination is alfo infoluble in water, but it has not as yet been found. SPECIES V. Mild Barytes intimately mixed 'with a notable Proportion of Silex and Iron. I mention this fpecies on the authority of Mr. fi'mdheim. 4 Berlin Schrift. 397. It is infoluble in. acids, and of a fparry texture; but, as he fays it becomes foluble after cal- cination with oil, I mould be inclined to judge it rather a barofelenite, SPECIES VI. 58 , Elements of Mineralogy. SPECIES VI. Barofelenite mixed 'with a notable Proportion of Site*, Mineral Oil and Terrene Salts^ Liver Stone, Lapis Hepaticus. It's colour is white, grey, yellow, brown, or black; it is generally compaft, but not fo hard as to give fire with fteel ; its texture is either equable or laminar, fcaly or fparry* and it takes a poliih as alabafter, It does not effervefce with acids. When calcined, it is partially reduced to a fort of Plaifler of Paris. It emits a fmell of hepar fulphuris, at leaft when rubbed. According to Mr. Bergman^ 100 parts of it afford 33 of barofelenite, 38 of fil,ex, 22 of alum, 7 of gypfum, and 5 of mineral oil. The increafe proceeds from the water of chryfta- lization. CHAP. VI, Muriatic Genus. Under this genus I include not only thofe Earths and Stones in which magnefia predo- minates, but alfo thofe in which the filiceous genus Muriatic Genus. 59 genus predominates, if magnefia be, next to the filiceous, the moft copious ingredient, and the compound poflefles the characters of the muriatic, and not thofe of the filiceous genus. SPECIES I. Combined with the Serial Acid, and barely mixed 2- 7 fail. p. 18. SPECIES II. Combined with Aerial Acid, above four times its 'weight of Silex, and afmalkr fropor- tion of ArgilL I. VARIETY. Steatites. This is always of a green or greenifh co- lour, and fo foft as to be fcraped by the nail ; of a foft foapy feel : its texture undiftinguifh- able; its fpecific gravity from 2,433 to 2>7^ It is not eafily diffufible in water, nor ren- dered duftile by mixture with it. It does not effervefce with acids, and is very flowly and only partially foluble iu the three mineral acids. In fire it hardens, but is infufible per fe^ and becomes whiter. It is imperfedtly melt- ed by mineral alkali and niicrocofmic fait, but more perfe&ly by borax. It is apt to corrode the crucibles; According 62 Elements of Mineralogy. According to Mr. Bergman's analyfis, 100 parts of it contain 80 of filex, 17 of mild magnefia, 2 of argill, and nearly i of iron in a femiphlogifticated ftate. II. VARIETY. Soap-rock^ Lapis Ollaris* Pot-pone^ Speck/iein of the Germans^ Spanifh Chalk. 2 Margr. 14. This is of a yellow colour, and fometimes whitifh, and but rarely black : it is alfo fomewhat harder than the former variety, and probably the proportion of argill is fomewhat greater, but in other refpe£ts it perfectly refembles it. The black contains a mineral oil. This ftone is eafily worked and turned, in- fomuch that pots and mortars are often made of it. Mr. Gerhard remarks, that the Swedifh fpeckftein often effervefces with acids, and contains calcareous Earth, but that of Saxony and Silefia never. The limeftone is merely an accidental mixture. 4 Berlin^ Schrift* 300. SPECIES III. Muriatic Genus. 63 SPECIES III. Mild Magnefia combined with Silex, Calcareous Earth, and a fmall proportion of Ar gill and Iron* I. VARIETY. Fibrous AfoeJloS) Alwnen Plumofum. The colour of this ftorie is generally green- ifh, and it confifts of .filaments either parallel to, or interwoven \vith each other. It is rough to the touch, and brittle and uneven in ks fraflure, hence it does not ftrike fire with fteel. Its fpecific gravity is from 2,5 to 2,8. It does not effervefce with acids, and is fo- luble in them but partially, and by particular management. When fufficiently heated, it becomes fome- what whiter and more brittle, but is infufible per fe by the blow-pipe, unlefs it contains a notable proportion of calx of iron. It is difficultly fufible with mineral alkali, more eafily with borax and microcofmic fait, and with fcarce any effervefcence. It is never tranfparent, and in that refpe£t, and in the unevenefs of their fradure only, fome forts of 64 Elements of Mineralogy. of martial afbeftos differ in external appear- ance from fome forts of flioerl. According to Mr. Bergman, this variety contains from 53 to 74 parts of filex, from 12 to 28 of mild magnefia, from 7 to 14 of mild calcareous Earth, from 2 to 6 of argill, and from I to roof iron per cent, ico parts martial afbeftos contain 62 of filex, 13,7 of magnefia, 12 of calcareous Earth, 1,7 of argill, and 1 0,6 of iron ; yet it gives in fufion a white flagg. - II. VARIETY, Coriaceous Ajbeftos, Suber Montanum, Aluta Montana^ Mountain Cork, Leather, <&c. This fort of albeftos refembles in texture thofe fubftances from which it borrows thefe fanciful appellations. It is eaiily diftinguifhed by its elafticity and lightnefs, for it floats a long time on water. In other refpe&s it re- lembles the former fpecies, except that its colour is either white, yellow, brown, green, or black. loo parts of it contain from 56 to 62 of filex, from 22 to 26 of mild magnefia, from 10 to 12 of mild calcareous Earth, from 2 Jto 2,3 of argill, and about 3 of iron. SPECIES IV. Muriatic Genus. 65 SPECIES IV. . Mild Magnefia combined 'with Sikx, mild Cal* car eons Earth, Barytes, Argill and Iron. Amianthus. In ftrufture this fpecies refembles the firft variety of the foregoing ; confifting of long parallel fibres, in fome degree flexible, and foft to the touch. The furface of its frac- ture is alfo uneven. Its colour, white, grey, greeniih or reddifh : its fpeciric gravity 2,913. It does not effervefce with acids, and is difficultly, and but partially foluble therein, It is fufible per fe in a ftrong heat, and alfo with borax, microcofmic fait, and mineral alkali, with effervefcence. In fufion it again chryftalizes in filaments, but in a ftill ftronger heat it forms a green glafs, which corrodes the crucibles, as Mr. SauJJure has obferved. 100 parts of the Amianthus of Tarentaife examined by Mr. Bergman , afforded him 64 of filex, 1 8, 6 of magnefia, 6,9 of calcareous Earth, 6 of barytes, 3,3 of argill, and i,a of iron. F SHCIIS V. 66 Elements of Mineralogy. SPECIES V. Pure Magncfia combined 'with fbmething more than its o*wn weight of Silex, about 4. of its •weight of argill, nearly y of its 'weight of water, and about I or 2 tenths of its •weight of Iron. Serpentine, Lapis Nephriticus, Gabro of the Italians. In refpeS to colour, as well as compofition, this ftone is fufceptible of great variety, for it is found either white, green, brown, reddifh brown, yellow, light blue, black, fpotted, or ftreaked with veins of different colours. Its texture is either indiftind, obfcurely laminar, or fibrous. It is harder than foap-rock, but not fo hard as to give fire with fteel, and lefs fmooth to the touch, but fufceptible of a good polifh, looks like marble, and is often in thin pieces femi-tranfparent, Its fpecific gravity is from 2,4 to 2,65, It does not effervefce with acids, but is flowly and partially foluble in them. It melts per fe in a ftrong heat, and preys on, the crucibles. Vogel, 103. In a lower de- it hardens. According Muriatic Genus. 67 According to the analyfis of Mr. Bayen, 100 parts of it contain about 41 of filex, (which he takes rather to be mica) 33 of magnefia, 10 of argill, 12 of water, and about 3 of iron. The ferpentine of Corfica contains a larger proportion of argill and a fmaller of filex. The greener forts of this ftone have been called nephritic. SPECIES VI. Pure Magnejia intimately mixed 'with nearly twice its 'weight of Si/ex, and lefs than its own 'weight o Venetian Talc. Its colour is white, grey, yellowifh, or greenifti : it is foft and foapy to the touch, and in thin pieces femi-tranfparent : it is compofed of very thin laminae difpofed in a laminar or filamentous form, much tenderer and more brittle than thofe of mica, but like this it has a metallic luftre: its hardnefs is fo inconfiderable that it may be fcratched with the nail : its fpecific gravity is' 2,729. It does not effervefce with acids, and is fo- luble therein very difficultly by particular ma- nagement, and only in part. F 2 In 68 Elements of Mineralogy. In fire it becomes more brittle and whiter, but is infufible perfe by the blow-pipe, and fcarcely fufible by fixed alkalis, but more completely, and with little effervefcence, by borax or microcofmic fait. This talc contains fomething lefs than 50 per cent, of filex, and about 2 percent, of iron. The magnefia is in fmalier quantity, but it exceeds the argill : the exaft proportion I have not found. Mufcovy talc confifts of broad, elaftic, flexible, tranfparent leaves, and differs exter- nally from mica only in being fofter and more foapy to the touch. SPECIES VII. Combined with the Sparry Acid. This combination is fcarcely foluble in wa- ter, but has not yet been difcovered ia nature. SPECIES VIII. Combined 'with the Tungften Acid. This compound when artificial is alfo info- luble, but has not as yet been obferved native. Compound Muriatic Genus. 69 Compound Species in which the Muriatic Genus predominates. SPECIES I. Compounds of the different Jimple Muriatic Species •with each other. I. VARIETY. i. Steatites mixed with Talc, Craze de Brianfon. It is generally grey, yellow, or greenifh : it feems more argillaceous than pure fteatites, and contains more iron. Mr. UArcet found it fufible in a porcelain heat. II. VARIETY. 1. Serpentine mixed with veins or (pots of green Steatites. 2. Red Serpentine mixed with veins of Afbeftos. SPECIES II. Compounds of the Muriatic and Calcareous Species. i, Red, green, yellow, or black Serpentine, with veins or fpots of white Calcareous Spar Potzevera. The black is called Nero di prato ; F 3 the 70 Elements of Mineralogy. the green Verde di Suza ; but thefe names are not reftrained to this fpecies. 2. Serpentine with veins or fpots of Gyp- fum. SPECIES III, Compounds of the Muriatic and Barytic Species, I. VARIETY. Serpentine with veins or fpots of barofele-> nite. SPECIES IV. Compounds of the Muriatic and Argillaceous Species. I. VARIETY. I. Steatites mixed with a notable propor- tion of indurated Clay. It is lefs foft to the touch, and fomething harder than the pure fteatites : its colour is grey or greenifh brown : it frequently contains alfo mica or talc, anc} fometimes a notable proportion of iron, and then it is red. The talcofe is frequently cal- led French chalk, or Cyaie de Brian f on. 2. Steatites., Muriatic Genus. 7 1 2. Steatites mixed with Shiftus, or bitu- minous Shiftus. This is blue or black, and rougher to the touch than pure fteatites. 3. Serpentine mixed with veins or fpots of Shiftus. 4. Soap-rock mixed with Mica. Cronft. § 265. Grey, yellow, or greenifh. SPECIES V. Compounds of the Muriatic and Siliceous Species. i. Serpentine with veins of Quartz or Feltfpar, or Shoerl, CHAP. VII. Argillaceous Genus. SPECIES I, Saturated with Aerial Acid* Lac Lun&. This fanciful name was heretofore thought to denote a very fine fpecies of calcareous Earth, but Mr. Scbreber has lately fhewn that the Earth to which this name is given, is a very uncommon fpecies of argil i. It is generally found in frnall cakes of the V 4 hardnefs 72 Elements of Mineralogy. hardnefs of chalk, and like that, it marks white : its hardnefs is nearly as that of ftea- tites, and does not feel as fat as common clay does : its fpecific gravity is 1,669 : *ts colour is fnow white. When examined with a mi- crofcope, it is found to confift of finall tran- fparent cryftals ; and by his experiments it plainly appears to be an argill faturated wi'h fixed air. It effervefces with acids, and con- tains a very fmall proportion of calcareous Earth, and lometimes of gypfum, and fome feeble traces of iron. It is found near Halle s. 15 Naturforfch. 209. SPECIES II. Combined but not faturated with Serial Acid, in a loofe or femi-indurated form^ and mixed •with fine Quartz or Silex tn various propor- tions, a fmall quantity oj Water, and gene- rally of Iron. Clay, Creta of the Italians. This fpecies receives a number of different denominations, arifing from its hardnefs, fu- fibility or infuiibility, or the different ufes it is applied to, or relative to its colour, or origin; fuch as ftone clay or lithomarga, fufible or apyrous clay, marl, Fuller's earth, pipe clay, kaolin, brick clay, umber, coloured clays, boles, pouzzolana, terras, tripoli, &c. All clays Argillaceous Genut. 73 clays are more or lefs eafily diffufible in wa- ter, which they rnbibe with more or lefs avi- dity, according to their previous compadlnefs, and if they contain much air they froth with water, burft and tali to pieces : when they have imb.bed it rhey are more or leis du£til and vicid, according as the fand they are mixed with is more or lefs fine. They contract ia drying, and crack when heated, they con- trad: ftill m"> re, and harden to fuch a degree as to give fire with fteel. They do not effer- vefce with ack!s, un lefs they contain ma^nefia or calcareous Earth. The finer clays have a fmooth, and in lome meafure, a foapy feel. Thefe are the properties of pure argilla- ceous Earths ; yet moft clays contain but from 35 to 48 per cent, of this Earth, the remain- der confifts of fine filiceous Earth, and a little water. On the fubtility and purity of the fili- ceous part, the finenefs of clay principally depend. Many clays contain a little volatile alkali, and fome the vitriolic acid ; probably this lat- ter is united to the argill in the ftate of em- bryon allum, that is, in fuch proportion as not to render it foluble in water. Moft of them contain alfo a finall proportion of iron. Fufible 74 Elements of Mineralogy. Fufible Clays. All clays, which, befides argillaceous and iiliceous Earths, contain a mixture of calca- reous or muriatic Earths, or gypfum, or fluor, or felt fpar, or iron, are more or lefs fufible, according to the proportion of thefe foreign ingredients. Apyrous Clays. Clays that confift of argillaceous and fill- ceous Earths fingly, without any mixture of iron or other metallic fubftance, or at leaft only in an inconfiderable proportion, are in- fufibl1. Such is that found near Plombiere. Mem. Par. 1778, p, 433. Argillaceous Marl, Any clay that contains from 20 to 50 per cent, of mild calcareous Earth, comes under this denomination. It differs prodigioufly in point of hardnefs and colour : the hardeft is called hthomarga^ or ft one marl. The beft for agriculture is the grey or white ; the co-* loured generally contain metallic particles : when it contains 20 or 30 per cent, of calca-- reous Earth it is fufible perje. The coloured as they contain more iron, are ftill more Argillaceous Genus. 75 more fufible. This fpecies of marl falls to pieces more difficultly, either in water or air, than calcareous marl. Indurated marls, of a quadrangular form, have been called Ludi helmontii. Fuller's Earth. This is moftly of a white, grey, bluifh, or yellowifh colour, compact, femi-indurated, of a lamellar texture, and often conchoidal in its fracture ; confifting of very fine particles, fmooth and fomewhat foapy to the touch : it burfts and is diffufible in water, with which it often froths like foap : it does not effervefce with acids ; in a ftrong heat it melts into a flag. Microcofmic fait affects it but (light- ly; mineral alkali more powerfully, and with much effervefcence, but bora:$ melts it moft completely. Different fpecimens of it, from various countries, afforded Mr. Bergman from 47 to 60 of filiceous Earth, from 1 1 to 25 of ar- gillaceous, from I to 6 parts of magnefia, from 3 to 7 of mild calcareous Earth, from 3 to 5>5 °f dephlogifticated iron, and from 15 to 1 8 of water, mixed with a very minute proportion of marine acid ; but this laft was found only in a few of them, Its fulling power 76 Elements of Mineralogy. power arifes from the property of clay to ab- forb oils, the finenefs of its particles, which do not injure the cloth, and its eafy diffufi- bility in water, which renders it capable of being wafhed off. Terra lemma is ayellowifh or flefh-colour- ed clay of this fort. Pipe Clay. Any moderately pure and fine white clay* which retains its colour in fire, is diftinguifh- ed by this appellation. That of Cologne is the pureft, and is infufible in the ftrongeft heat. Many of thefe clays become grey in a weak degree of heat, becaufe the mineral oil with which they are mixed burns to a coal* but in a ftronger heat they again become white, this coal being confumed. Porcelain Earthy or Kaolin. This differs from the former chiefly in the finenefs or fubtility of the filiceous ingredient* It fometimes effervefces with acids, either be- caufe it contains cryftalized argill, or mag- nefia, or calcareous Earth : it alfo abounds in talcofe particles. It never contains any oily matter, and therefore retains its colour in every degree of heat. Brick Argillaceous Genus. 77 Brick Clay. Its colour is various, reddim, Wuifh, or yellowifh : it always contains iron, and melts into a flag. The beft fort contains little or none of calcareous Earth, but a good deal of a coarfe filiceous fand. Coloured Clays. Yellow^ red) and brown clays contain moft iron, fometimes difperfed through them, and fometimes united to the iiiiceous part : in this cafe they are more difficultly fufible. The yellow calx of iron is more dephlogifticated than the red, and the red more fo than the brown. When thefe clays contain about 14 or 15 per cent, of iron, they become mag- netic after calcination. Red chalk, Rubricafabrilis, is,~according to Mr. Rinman, either a clay intermixed with the red calx of iron, which hardens in fire, and then becomes magnetic and browner, and in a ftronger heat melts into a black glafs, and contains from 1 6 to 1 8 per cent, of iron, (but fometimes it contains but 7 or 8 per cent, of iron, and then does not become magnetic by roafting) or it is an impure fteatites, mixed with clay and calx of iron. Hijloria Ferri, § 189. Blue . 78 Elements of Mineralogy. Blue Clays. Thefc fometi mes lofe their colour and become white when heated, and confequently contain but little of iron, but owe their colour to an oily matter, which is diflipated by heat ; others owe their colour, according to Mr. Mantlet, to a mixture of pyrites. Mineralogie, p. 339. Mr. Beaume fays, that blue clays contain the vitriolic acid, but he probably found it only in the pyritical clays, for in other forts Mr. Woulfe could difcover none. Phil. Tranf. I779» P- 20' Mr. Bergman found fome which contained copper and a little of cobolt. Rin- man mentions a blue lithomarga, which con- tained 1 3 per cent, of iron, 4 of lead, and fome veftiges of zinc. Hifl. Ferri, § 201, p. 712. Umber. A brown orblackifh fubftance, which ftains the fingers, and is very light; it has long been taken for a clay, but Mr. Hupfch, Mem. Ber- lin, 1777, has difcovered it to confiil of par- ticles of decayed wood, mixed with bitumen ; yet it is certain that this name hath alfo been given to a fort of brown ochre, of the fame colour, which becomes red when flightly heat- ed, but in a ftronger heat is again brown and magnetic, and in a ftill ftronger melts into a black glafs. It does not effervefce with acids before Argillaceous Genus. 79 . before roafting, but after that the martial part is fallible. Green Clays. Some forts are faid to redden in fire, and contain iron. Mr. Bergman has found fome which contain copper and cobalt ; to feparate which he precipitated the copper by iron, and digefted the refiduum in diftilled vinegar. Other forts are faid to contain nickel. Black Clays. Thefe are faid to be bituminous. Variegated. The moft remarkable of this fpecies is the Terra miraculofa Saxonitf, which is a beautiful indurated clay, of a purplifh colour, with white, yellow, red, or brown veins or dots. Bole. Is a term of uncertain fignification, and fhould therefore be baniftied. Some beftow this name on very fmooth compact clays, con- fifting of the fineft particles : others require befides, that their colour ihould be red, yel- low, or brown, and that they fhould contain iron. The recj generally blacken in fire, 2 Bergm* So Elements of Mineralogy. Bergm. 476, yet do not become magnetic. Rinman, § , 89. The yellow, when heated9 become firft red, and in a ftrong heat, brown or black. Calamita bianca of the Italians is a white bole, ftriated like afbeftos. Ferber* •It ally ^ 122. Terra figillata rubra contains calcareous Earth, and becomes magnetic after torrefadtion. Rinman^ § 189, Of Volcanic Origin. Pouzzolana. This is of a grey, brown, yellowifh, or blackifh colour, loofe, granular, or dully, and rough, porous and fpungy, refembling a clay hardened in fire and then reduced to a grofs powder. It contains, mixed with it, various heterogenous fubftances : its fpecific gravity is from 2,5 to 2,8, and it is in fome degree magnetic.* it fcarcely efftrvefces with acids, though partially ioluble in them : it melts eafily perfe : but its moft diftinguifhing property is, that it hardens very fuddenly when mixed with ^ of its weight of lime and water, and forms a cement, which is more durable in water than any other. According to Mr. Bergman's analytic, loo parts of it contain from 55 to 60 of filiceous Earth, 19 or 20 of argillaceous, 5 or 6 of calcareous, and from 15 to 20 of iron. 3 Bergm. 193. It is evidently a martial argillaceous marl that Argillaceous Genus. 8 1 that has fuffered a moderate heat. Its harden- ing power arifes from the dry flate of the half-baked argillaceous particles, which makes them imbibe water very rapidly, and thus ac- celerates the defication of the calcareous part ; and alfo from the quantity and lemi- phlogifticated ftate of the iron contained in it. It is found not only in Italy but alfo in France, in the provinces of Auvergne and Limoges, and alfo in England, and elfewhere* Traqfsy or Terras, This differs but little in its principles front pouzzolana, but is much more compact and harder, porous and fpungy. It is generally of a whitim yellow colour, and contains more heterogenous particles, as fpar, quartz* fhoerl, &c. and fomething more of calcareous Earth : it effervefces with acids, fs magnetic, and fu- fible perfe. When pulverized, it ferves as a cement, like pouzzolana. It is found in Ger- many and Sweden. Tufa. Volcanic aflies concreted with various other fpecies of (lone, but in which argill predo- minates, forms the ftone thus called : it is harder than traafs, but ftill porous and fpungy. G White -Elements of Mineralogy. White Volcanic Earth. That of Solfatera, examined by Mr. Berg- man, was found to confift chiefly of filex, mixed with about 4 per cent, of argill, and 8 per cent, of allum. 3 Bergm. \ 98. Tripoli. Its colour is either white, grey, yellow, reddifh, or brown, either indurated and brit- tle, or loofe, powdery, and rough : it does not foften in water, nor effervefce with acids. According to Mr. UArcet, it is verifiable />#" fe in a porcelain heat long continued ; and ac- cording to Mr. Bergman, it yields to borax and microcofmic fait, but fcarcely to fixed al- kali. Mr. Haafe, who has lately anal y fed it, found ico parts of it to contain 90 of filiceous Earth, 7 of argill, and 3 of iron ; but the red fort probably contains more iron. Ac- cording to Mr. Gerhard, magnefia has fome- times been extracted from it. It is evidently a volcanic product ; for a coal-mine nearS/. Eftienne having accidentally taken fire, and the fire in its progrefs having extended to fome ftrata of fhiflus and bitumen, tripoli was found in thofe parts of the ftrata that Argillaceous Genus. 83 that the fire had a£ted upon, but not in any other. Mem. Par. 1769, p. 276. The rotten Jlone of Derbyfhire is, according to Mr, Ferber^ a tripoli mixed with calcareous Earth. SPECIES III. Barely fat ur ate d 'with Vitriolic Acid. Embryon Allum. This fpecies was firft difcovered by Mr. Beaume ; it forms fmall fcaly chryftals like mica, which require 1450 times their weight of water to diffolve them in the temperature of 60? It is no where found fingle, but ge- nerally mixed with clays, from which it may be feparated by boiling, and diffolved in water, to which it gives an earthy tafte, and is fepa- rable by the affufion of lime water, which precipitates the argill. SPECIES IV. Barely fat ur at cd 'with Marine Acid* Embryon Marine Allum. As a folution of marine alum, completely faturated with argill, forms alfo a very diffi- G 2 culcly 84 Elements of Mineralogy. cultly foluble compound^ and as many clays are found to contain the marine acid, it is probable that this fpecies exifts in them, though it hath not yet been noticed. In ajlony Form. 'Under this head I comprehend all thofe ftones which, although the filiceous genus pre- dominates in their competition, and the argil- laceous, with refpect to quantity, obtains only the fecond place, yet do not poffefs the cha- racter of filiceous ftones, as they do not ftrike fire with fteel ; and on the contrary, I exclude thofe which poflefs the characters of filiceous Earths, though they contain the argillaceous in greater quantity SPECIES V. Arglll combined 'with 1,36 its weight of Silex> °>7 2/ *ts ^ tight of pure Mngnefia^ and 0,5 of its 'weight of highly dephlogijlicated Iron. Pure Mica. This ftone, in its pureft ftate, is colourlefs ; but either from a leis intimate combination, or from a mixture of fome fuperfluous ingre- dient, principally iron, it is found of diffe- rent colours, white, red, yellow, green, brown, or black, ^the white and yellow fort havs Argillaceous Genus. 85 have a fplendid metallic appearance) fmooth, but not greafy to the touch, which diftin- guifhes it from talc. Its texture is always lamellar or fcaly, and the lamellae, or fcales, are flightly flexible and often elaftic; thefe fcales are fometimes parallel to each other, fometimes interwoven, fometimes wavy, or undulated, and fometimes they reprefent fila- ments. Its fpecific gravity is from 2,535, to 3,000 when loaded with iron. It does not effervefce with acids, and is in- foluble in them without particular manage- ment, but after it has been calcined with 4 times its weight of fixed alkali, it effervefces ftrongly, and is in great meafure foluble. The pure colourlefs mica is infufibie ferfe^ and fcarcely melts even with mineral alkali, but yields more readily to borax or microcof- mic fait, with fcarce any effervefcence ; but the coloured forts were found by Mr. Saujfure to be fufible per fe, though with difficulty, for they require a ftronger heat than ihoerl does. 100 parts of the colourlefs kind contain 38 of filex, 28 of argill, 20 of magnefia, and 14 of the moft dephlogifticated calx of iron. Martial mica contains befides, 1Q or 12 per cenj. of a more phlogifticated @ 3 calx 86 Elements of Mineralogy. calx of iron, from whence its various colours are derived, and a proportionably imaller quantity of the other ingredients. Argillaceous FiJ/ile Stones. Thefe and many other of different genera, have been comprehended under the denomi- nation of Schijli, but to avoid ambiguity, I think it expedient to confine this name to flones of the argillaceous genus. SPECIES VI. Roof Slate, Shijlus Tegularis. Of this fpecies there are many varieties, none of which have been hitherto analyfed, except the bluifh purple flate chiefly ufed here, which I have lately examined, and to which, as to a ftandard, I {hall refer the other forts. I, VARIETY. Argill Intimately mixed 'with 1,77 of its weight of Siliceous Earth, 0,3 of its 'weight of Magnefia-) 0,15 of Calcareous Earth, both Jlightly aerated, and nearly 0,54 of its weight of Iron, befides ajlight admixture of Mineral Oil, Bluiflo Purple Slate. It does not ftrike fire with fteel, and may be {lightly fcraped with the nail ; it is very brittle, Arglllactoue Genus. 87 brittle, and of a lamellar texture : its fpecific gravity is 2,876: when in pieces of J of an inch thick, or lefs, it gives a clear found if ftruck : its grain is moderately fine : it is never tranfparent: it flightly effervefces with acids when reduced to powder, otherwife not : when heated red, it lofes fomSthing more than 2 per cent, of its weight, flightly detonnates with nitre, and then affumes a brownifh red colour, but calcination does not render it magnetic : in a ftronger heat it is fufible perje^ and forms a black fcoria : it is difficultly diffolved by mineral alkali in the dry way, more eatily by borax, though with lit- l£ effervefcence, and alfo by microcofmic fait with fome effervefcence, Mr Gerhard re- marks, that it melts with equal eafe in chalk or clay veflels. Dephlogifticated fpirit of nitre, after Hand- ing on it two months in cold, affumes a greea colour. I found 100 gr. of it to contain about 46 of filex, 26 of argill, 8 of magnefia, 4 of calcareous Earth, and 14 of iron. Part of the iron feems to be in a phlogifticated ftate, from its union with the oil, and part in a dephlogifticated ftate, or that of a red calx* This is united to the argillaceous part and filex, and is very difficultly feparated. 64 88 Elements of Mineralogy, II. VARIETY. Pale, Jlightly Purple, or bluijh Shiftus. This ftone is harder than the foregoing, its laminae thicker, and its texture coarfer : it feems to contain a larger proportion of the filiceous and a fmaller of the martial ingre- dient. III. VARIETY. Blue Sbi/lus. The proportion of the earthy ingredients being the fame as in 'the firft variety, that of the martial ingredient feems to be fmaller. Other flones are alfo ufed for covering houfes in various countries, but they are eafily diftinguilhed; as their laminae are much thicker, their furface more uneven, and their texture coarfer. They chiefly belong to the clafs of fand-ftones, or to the calcareous genus, IV. VARIETY, Dark Blue Slate> Shift us Script onus. It efFervefces more brifkly with acids, and feerns to contain more magnefia, and lefs iron, than Argillaceous Genus. 89 than the firft variety : its fpecific gravity is 2,701. SPECIES VII. Argillaceous Earth mixed 'with a variable Proportion of Pyrites^ 'with a little Mag- nefia and Calcareous Earth. Pyritaceous Shiftus. Its colour is grey, brown, blue, or black : it is more or lefs decompofable by expofure to the air, according to the quantity of the py- ritous ingredient and the ftate of the iron in the pyrites : if the iron be in a femiphlogifti- cated ftate it is eafily decompofed, but if the calx of iron be already much dephlogifticated, it will be decompofed but flowly, if at all. Aluminous fchiftus is of this fpecies, but will more properly be mentioned in treating of alum. SPECIES VIII. Slate, or Pyritaceous Shiftus 9 intimately mixed 'with a notable Proportion of Mineral Oil or Bitumen. Bituminous Scbiflus. It is generally black, of a lamellar texture, of different degrees of hardnefs, but never gives 90 Elements of Mineralogy. gives fire with fteel . it emits a ftrong fmell when heated, and fometimes without heat 5 does not fhew white when fcraped. SPECIES IX. Argill mixed with from 3 to 4 tenths of its •weight of Si/ex, and a little of the yellow or red Calx of Iron. I. VARIETY. Argillaceous Shift us ^ Flag ft one. This is of a grey, yellowifh, or reddifli white colour ; does not give fire with fteel, nor efFervefce with acids : its fpecific gravity is from 2,6 to 2,78 : it is in fome places ufed for covering of houfes, but moftly for floor- ing : it is fometimes compact, and fometimes fandy, like the next variety, and then its fpe- cific gravity is fmaller. II. VARIETY, Argillaceous Grit^ Free-ftone> Qr Sand-ftone. It is called free-ftone becaufe it may be cut eaf^ly in all directions : its texture is more or lefs po ous, equable and rough to the tout h : it exhales an earthy fmell when frefh broken and breathed upon : it does not give fire with iieel, nor efFervefce with acids. That Argillaceous Genus: 91 That from Hollington, near Utoxeter^ is of a whitiih or yellowifh grey, and its fpecific gravity 2,288. That from Kniperjly, in. Staf- ford/hire, is of a bluifh grey, and fo infufible as to be ufed for a fire-ftone : its fpecific gra- vity is 2,568- SPECIES X. Argillaceous Earth intimately mixed 'with 1,7 of its weight of Sikx, about 0,7 of its weight of mild Magnefia^ 0,09 of its 'weight of mild Calcareous Earth> and about its own weight of Jemlfhlogifticated Calx of Iron. Jlorn-ftone, Hornblende of Cronfted9 and Tal- cum Striatum of Rinnan, Mem. Stockh. 1 754, The general characters of this ftone, be- fides a partial folubility (though without ef- fervefcence) in acids, and a hardnefs never fufficient to ftrike fire with fteel, properties which are common to it with the former fpe- cies,) are ift> a fpecific gravity never lefs than 2,66, and frequently rifing to 3,88. 2d* a ftrong earthy fmell which it exhales on being breathed upon, or having hot water poured on it : 3d* a toughnefs or vifcidity perceived in pounding it in a mortar, like mica or horn, from whence it derived its name: 4th* its af- fording a greenifh grey powder when pound- ed ; 9 2 Elements of Mineralogy. ed ; 5th' fufibility per fe> as it is faid, though I could not melt it with the blow-pipe. It is frequently mixed with pyrites. I. VARIETY. Black Horn-ftone, Corneus Nitens Waller, Sp. 169. Its texture is lamellar or granular ; the for- mer is fometim^s fo foft as to be fcrapedvwith the nail ; its furface frequently as glofTy as if it had been greafed : its fpecific gravity is from 3, 6 to 3,88; it poflefles befides all the fpecific properties above- mentioned in a high degree : it does not detonate with nitre : it becomes of a fnuff colour when heated, and then flightly effervefces with diluted nitrous acid : its folution in this acid is of a greenifh colour. In order to difcover the principle on which its fmell depends, I boiled its powder in wa- ter, but did not find the water altered in tafte, nor did any teft I applied ihew any change in it. I found TOO gr. of the lamellar fort to con- tain 37 of filex, 22 or argill, 16 of magne- fia, 2 of calcareous Earth, (both in a mild ftate and 23 of calx of iron, not much de- phlogifticated. II. VARIETY, Argillaceous Genus. 93 II. VARIETY. Greenifh Grey Horn-Jtone. This is of a granular texture, or ftriated ; the fpecific gravity of the pureft fpecimen I examined is 2,683 : it is not fo foft as the fofteft of the former variety. I fufpect the common pale greenifh grey whetftone to be of this fpecies : it is of a clofe granular texture, exhales an earthy fmell, affords a greenifh powder, does not effervefce with acids, nor give fire with fteel; its fpecific gravity is 2,664; ^ contains "65 per cent, of filex. III. VARIETY. Klllas. This ftone is chiefly found in Cornwall ^ its colour is pale grey or greenifli grey ; its texture either lamellar or coarfely granular : the lamellar is fofter and lefs martial than the roof fhiftus : its fpecific gravity from 2,63 to 2,666. I found too grains of the lamellar fort to contain about 60 of filex., 25 of argill, 9 of magnefia, 94 Elements of Mineralogy. magnefia, and 6 of iron. The greenifh fort contains more iron and gives a greenifh colour to the nitrous acid. , SPECIES XL Argillaceous Earth intimately mixed with 4 times its weight of Siliceous, f its weight of pure Calcareous, and fome thing more than its weight of Iron. Toad-Jtone. Dr. Withering, who has given us an ana- lyfis of this (lone, defcribes it as being of a dark brownlfh grey colour, of a granular texture, not giving fire with fteel, nor effervefcing with acids : it has cavities filled with chryftalized fpar : it is fufible per fe in a ftrong heat. Phil. Tranf. 1782,^ p. 333- 100 parts of it contain 63 of filiceous Earth, 14 of argillaceous, 7 of calcareous, and 1 6 of dephlogifticated iron : it differs but little from bafaltes ; it is fofter, contains a fmaller proportion of iron, and a larger of filex. SPECIES XIL Argillaceous Genus. 95 SPECIES XII. Argill united to 2,3, or 8 times Its weight of Silex, about half its 'weight of pure Calca- reous Earth^ and from once to twice its •weight of Water, 'without any Iron, except accidentally. Zeolyte. This ftone is found of different degrees of tranfparency, or perfectly opake, either co- lourlefs, whitifh, yellowifh, greenifh, or red- difh ; its fhape is either pyramidical, colum- nar, tabular, oval, capillary, or amorphous ; its texture either granular, fcaly, or radiated ; the filaments diverging as from a central point, or indiftinguifhable. It does not give fire with fteel. Its fpecific gravity is from 2,1 to 3*15* but this laft is very rare. It does not eflervefce with acids, though it is partially foluble in them, but if inferted into a proper proportion of concentrated ni- trous acid, it forms a .gelatinous mafs, arifing from the fufpenfion and diffufion of the fill- ceous Earth contained in it ; but this property is not peculiar to zeolyte, as Mr. Pdlatier has fliewn, 96 Elements of Mineralogy. fliewn. 20 Roz. 42 9 * And fome few lytes do not becorae gelatinous. 3 Bergm* 228. When expofed to a ftrong heat it dilates and fwells, more or lefs, according to the proportion of water contained in it, and af- terwards melts per fe, more or lefs eafily, ac- cording to the proportion of calcareous Earth, into a frothy flag ; in the moment of fuiion it is faid to become phofphorefcent ; it alfo melts eafily, and with effervefcence, with mineral alkali ; fomething more difficultly with borax, but microcofmic fait has icarce any effecl: on it. When in fuiion, it fcarcely injures the crucibles. 22 Roz. p. 29. This difetibility is the fureft criterion whereby to diftinguifh zeolytes. The Upland zeolytes are difficultly fuiible. According to Mr. Bergmans analyfis, the red zeolyte of Adelfors contains 80 per cent, of filiceous Earth, 9,5 of argillaceous, 6,5 of pure calcareous Earth, and 4 of water. Van Troll's Letters, p. 370. The white, oval, radiated zeolyte of Pero* contains, according to Mr. Pelletier^ 50 of filex, 20 of argilL 8 of pure calcareous Earth, and 22 of water. 20 Roz. 420. Mr. Meyer found another of the radiated fort to contain Argillaceous Genus. 97 contain 58,33 per cent, of lilex, 1 7, j of argill, 6,66 of lime, and 17,5 of water. 4 Berlin Befcbaft.ip. 330. In general the cryftalized forts contain more water than the amorphous. Mr. Bergman found the zeolyte of Jemptland to contain 1 6 per cent, of calcareous Earth, and that of Fero to contain 25 per cent, of argill, fo that the proportions are very varia- ble. SPECIES XIII. Of Volcanic Origin. Argillaceous Earth imperfeftly united to 4 times its weight of Siliceous, and y of its 'weight of Iron. Pitch-Jlone> Lava. It is of a greyifh, greenifh, black, red, or brown colour, has the glaflfy appearance of a femi-vitrified fubftance, and melts eafily perfe : it often contains fubftances feemingly heterogenous : fome pieces of it do not give fire with fteel, and therefore belong to this genus, others do, and belong therefore to the iiliceous genus. According to Mr. WiegkVs analyfU- 1. 1 Nev. Endcck) p. 18, 100 parts of i* vontain H 65 98 Elements of Mineralogy. 65 of filex, 1 6 of argil], 5 of iron, the remaining 14 gr. were diflipated. SPECIES XIV. Arglll mixed with a notable Proportion of red Calx of Irony andfometimes Steatites. Red Ctialk. It hardens in fire, and then often becomes magnetic , in the ftrongeft heat it melts into a black glafs, which does not corrode the crucibles, as calcareous ores do: it affords 1 6 or 18 per cent, of iron; if it does not become magnetic it affords only from 7 to 14 per cent. Rinman Hiftoria Ferri, § 189. Compound Species in 'which the Argillaceous Genus predominates. SPECIES I. Compounds of the different Species of the Ar- gillaceous Genus. I. VARIETY. Micaceous Marl. II. VARIETY. Micaceous Shiftus, either Slate or Flag-ftone* HI. VARIETY, : Argillaceous G'enus. 99 III. VARIETY. Micaceous Sand-ftones. IY. VARIETY. Micaceous Horn-ftone. Green hornftone mixed with mica. Gron- ftein of Cronfted, § 267, frequently contains pyrites, and 20 per cent, of iron. V. VARIETY. Shiftus and Argillaceous Grit mixed in various Proportions. VI. VARIETY. Shiftus and Hornftone mixed in various Pro- portions* SPECIES II. Compounds of the Argillaceous and Calcareous Genus. . I. VARIETY. Bituminous Shiftus mixed 'with Limeftonc* Marmore Nero Antko. 100 parts of this contain 18 of mild calca- reous Earth, the remainder ihiftus, from H 2 which loo Elements of Mineralogy. which 1 8 parts of oil were extracted by dif- tillation, alfo argill, and magnefia, and 6 parts of iron, befides much that was not fe- parated. 12 Roz. 63. SPECIES III. Compounds of the Argillaceous and Barytical Genus. SPECIES IV. Compounds of the Argillaceous and Muriatic Genus. I. VARIETY. Shiftus mixed with Steatites or Soap~rock* II. VARIETY. Shiftus mixed 'with Serpentine, III. VARIETY. ISornftone mixed with Mica and Serpentine. IV. VARIETY. JSornflone i&xed with Mica and Steatites* or Soap-nock. V. VARIETY. Argillaceous Genus* toi V. VARIETY. Mica mixed •with Soap+rock, Schneideftein. When the mica prevails the texture is flaty. SPECIES V. Compounds of the Argillaceous and Siliceous Genus, none of 'which gives Fire with Steel* I. VARIETY. 1. Mica mixed 'with Quartz, Stellftein^ Cronjl* § 262 It is of a flaty texture and eafily divided, 2. Mica and Quartz, and a little Argill^ Saxum Novaculum Linnet. II. VARIETY. i. Horn/tone and Mica mixed nvith Quartz. 2. Horn/lone and Shoerl. This is alfo called Gronftein^ when the hornftone is green. 3. Hornjlone, Mica and Shoerl) Binda of the Swedes. H3 -It io2 Elements of Mineralogy. It fometimes contains alfo quartz and pyrites. Its fpecific gravity exceeds 3,000. III. VARIETY. White Clay mixed 'with Mica and Quartz, and of no particular texture. Greifl, of the Germans, or Growan of the Corni/b Miners. When the texture is lamellar and the ftone harder, it is called Gneifs. IV. VARIETY. Sand/lone mixed 'with Mica, and Feltfpar. SPECIES VI. Compounds of the Argillaceous with t*wo or more Genera. L VARIETY. Micaceous Porphyry. This confifts of agreenifh grey, micaceous ground, in which red feltfpar and greenifh foap-rock are inierted. SauJJure Voyage dans les Alpes, p. in," even the mica is not pure, he fufpe&s it contains hornftone, p. 127. II. VARIETY. Hornjlone mixed •with Veins of Spar and Quartz. Mentioned by Mr. SauJJure, p. 120, CHAP. Siliceous Genus. 103 CHAP. VIIL Siliceous Genus. All the (tones I place under this genus give fire with fteel, except opals, and yel- low carnelians; and none effervefce with acids, except Lapis Lazuli in powder, Bar- fhoerl, martial muriatic fpar, and Turky hone. SPECIES I. Quartz, Cryjlal. The ftones of this fpecies are in general the pureft of the filiceous genus, though moft contain a flight mixture of other Earths; the moft obvious diftindtion among them, arifes from their tranfparency or opacity. SERIES I. Tranfparent §>uartzy Cryftal. This is either colourlefs and cryftalized irt hexagonal pyramids, and then called moun- tain cryftal, or in various other forms, or amorphous. Its fpecific gravity is from 2,65 to 2,7; its texture lamellar and generally ihattery, its appearance glafly ; it cracks and lofes its tranfparency when heated ; it pof- feffes all the other properties of pure filiceous H 4 Earth. 1 04 Elements of Mineralogy. Earth. Mr. Bergman has extrafted from loo parts of mountain cryftal, about 6 of argill, and i of calcareous Earth. 2 Bergm. 112. So alfo has Mr. Abilgaard. Denfk. Shrift. 1781. Yet Mr. Gerhard fays, that fome are ib pure as to contain neither. Gerb. Bey f rage, 78 and 85. He alfo fays that the amorphous cryftals, though colourlefs,1 being long digefted in acids, afforded when treated trith pure pruffian alkali, fome traces of iron, ibid. 85. The pureft and moft tranfparent of thefe cryftals form the falfe diamond* called brif- tal, or kerry ftone, diamant SAlengon, &c. The coloured tranfparent cryftals derive their tinge generally from metallic particles in exceeding final* f>: oportion ; they all loofe their colour whence .ted; thefe form the falfe Gems. The moft remarkable are the red^ from Oran, in Barbary\ falfe rubies. Yellow. From Bohemia; falfe topazes. Green. Falfe emeralds and prafius. gi c v Ffom Bohemia and Saxony. It is faid that brown cryftals may be cleared by boiling them in tallow. 7. Roz. 360. Mr, Siliceous Genus* 10; Mr. Bergman has formed perfect cryftals by diflblving filiceous Earth in the fparry acid, and fuffering it to cryftalize flowly. It is probable that nature forms them in a long courfe of time from a folution or diffu- fion of this Earth in pure water, or water that holds a little argill or calcareous Earth which probably enable it to take up more of the filiceous Earth than it otherwife could. Perhaps the experiment which once fucceeded with Mr. Achard) was owing to fome fuch caufe. SERIES II. Opake Quartz, or Pebbles. Thofe are alfo cryftajized, or amorphous, either white, grey, or yellowifh, or tinged of other colours by metallic particles. The former are lefs pure than thofe of the firft feries, containing a larger proportion of argill, or at leaft the argill is lefs perfectly united with the filiceous part. Their fpecific gra- vity is from 2,4 to 2,7 ; their furface either rough, or fmooth and fhining, the laft are called fat quartz : the texture either lamellar or granular j they crack like the former in fire, and become of a duller colour ; when rubbed againft each other they emit a phofphoric fmell. They are often found in round mafles in the beds of rivers, The 106 Elements of Mineralogy. The Coloured Opake Quartz are either. Blacky being mixed with a large proportion of iron. Red, according to Cronfted they contain copper, but Mr. Bergman could find none in them. 2 Bergm. 430. Blue, from Uto in Sweden. Green> found at Adelfdorfm Sweden^ SERIES III. Arenaceous Quartz or Sand. Though the powdery ftate of other ftones does not defer ve any particular notice: yet that of quartz or filex does, from the great ufe that is made of it, and from its feeming to poflefs properties which are incompatible with it in a grofler ftate. It is of various colours and incapable of forming a mafs or hardening with water, the pureft is white, the minute particles of which, when infpe&ed through a lens are tranfparent. It is feldom perfectly pure ; Mr. Achard fays that the fine white fand of Freyenivald, which is ufed for the porcelain manufactories contains % of its weight of argill and calcareous Earth, but this I fhould rather take to be a petro-filex in Siliceous Genus. 107 in powder. The finenefs of fome fpecies of fand is fo great as to pafs through fie ves, that contain 10,000 vacuities in the fpace of an inch, as Mr. Wedgeivood one of the moft celebrated manufacturers of earthen ware in Europe, has aflured me. Hence this Earth has been found fufpended in fome waters in the quantity of i grain in a gallon. See 2 Bergm. 47, and Cadet in the Memoirs of the French Academy for 1 767. SPECIES II. Siliceous Earth intimately mixed and partly combined 'with about \ of its 'weight of Ar- gill, and ^ of its 'weight of Calcareous Earth. Common Flint or Pebble, Hornflein^ Kiefel of the Germans. This ftone is found of all colours, or va- riegated with veins of different colours ; it is commonly covered with an opake white cruft, which feems of the fame nature, but more imperfectly combined ; this cruft ad- heres to the tongue like clay, yet ftrikes fire with fteel, fo that probably it contains a lar- ger proportion of argill than the kernel. Flint is always femi-tranfparent in thin pie* ces ; its hardnefs is various, though it always gives fire with fteel ; its texture is folid, whereas, to8 Elements of Mineralogy. whereas that of quartz is (hattery ; it breaks with fmooth furfaces, one of which is con- vex, the other concave ; it is never found cryftalized, but rather in feparate irregular nodules, fcattered through other flrata, and plentifully in England in beds of chalk; it has feldoin any fiffures, with which quartz abounds ; its fpecific gravity is from 2,65 to 2,700. Flints are infufible per fe in the ftrongeft fire, but generally become white and brittle by reiterated calcination, which feems to in- dicate that they all contain a little water ; and hence alfo, their decrepitation, when heated ; The fame may be faid of quartz ; they are affe&ed by fluxes in the fame manner as the pureft ftones of this genus. The common brown flint exhibited on Mr. Wiegleb*s analyfis 80 per cent, of filiceous Earth, 18 of argill, and 2 of calcareous. 6 N. Aft. Natur. Curiof. p. 408. Coloured flints undoubtedly contain metallic particles. To this fpecies we muft alfo annex the finer flints commonly called Egyptian pebbles^ hsemachates, ftigmites, filex fardus. Thefe differ from common flints; ift* in this, that they are lefs, if at all tranfparent ; 2d. that their texture is finer, harder, and clofer, and theif Siliceous Genus. io and Cambuya. A bafer fort I 3 is li 8 Elements of Mineralogy. is found in Finland, Bohemia, Silefia^ Saxony and Hungary, II. VARIETY. ICdloiv. Topaz, Hyacinth. Topas is of a gold colour; its texture fo^ liaceous ; its form cubic, parallelipedal, or prifmatic ; its fpecific gravity from 3,46 to 4,56 ; it lofes its colour only in a very iirong heat, and of the ufual fluxes it yields only to borax and microcofmic fait. According to Mr. Bergman^ 100 parts of it contain 46 of argil}, 39 of filiceous Earth, 8 mild calcareous, and 6 of iron. Its great fpecific gravity ihews thefe Earths to be very perfectly united. Oriental hyacinth is of a reddifh yellow colour, generally cryftalized in a prifmatic form ; in a ftrong heat it becomes paler, and according to Mr. Achard, may be melted in a wind furnace in 2 hours, According to Mr. Bergman, 100 parts of it contain 40 of argill, 25 of filex, 20 of jnild calcareous Eartfy, $nd 13 of iron; and according Siliceous Genus. 1 1 9 according to Mr. Achard, 41,33 of argill, 21,66 of filex, 20 of calcareous Earth* and 13,33 of iron. Hyacinths are found in Poland^ Bohemia^ and Saxony. III. VARIETY. Green. Emerald, Chryfolite, Beryl. The colour of emerald is pure green ; it is fometimes found in round flat pieces, but moftly cryftalized in hexagonal prifms ; its fpecific gravity is from 2,78 to 35711. It is the fofteft of all the precious ftones. According to Mr. Achard, it preferves its colour in a porcelain heat, and only becomes more opake ; in a ftronger heat it melts into a flag. Mem. Stock. 1768. Like the fore- going it eludes the force of mineral alkali, but yields to borax and microcofmic fait. With the former, according to Mr. Qulft-> it gives a colourlefs gl,afs. 100 parts of it contain, by Mr. Bergman** analyfis, 60 of argill, 24 of filex, 8 of cal- careous Earth, and 6 of iron j and by that of 1 4 Mr, 1 20 Elements of Mineralogy. Mr. Achard, 60 of argill, 21,66 of filex, 8,33 of calcareous Earth, and 5 of iron. It was antiently found in Egypt 9 now chiefly in Peru. Chryfolite^ or Beryl, is of a light yellowim green ; it melts per fe into a flag ; it is fofter than cryftal; it yields only to borax and microcofmic fait, and is icarcely affected by alkalis : when ready to melt it becomes phof- phorefcent, Aqua Marine f augites) is of a bluim green \ it melts per fe by the blow-pipe. IV. VARIETY, * Blue, Sapphire. Its colour is fky blue ; its texture foliace-* ous; its form hexangular or polyangular prifms or parallelipeds ; its fpecific gravity from 3,78 to 3,994 ; the oriental preferves its colour in a porcelain heat, and will not TL\t\iperfe9 but that of Brazil lofes its colour; it is affected by fluxes as the other varieties. Mr. Bergman found 100 parts of this ftone to contain 58 of argill, 35 of filex, 5 of Siliceous Genus. 1 2 1 jnild calcareous Earth, and 2 of iron ; and Mr. Achard 58,33 of argill, 33,33 of filex, 6,66 of calcareous Earth, and 3,33 of iron. Jewellers mention white, green, and yel- low fapphires, or pale red. SPECIES VII. Amethyji, Some of this fpecies are as tranfparent as the former ftones, others duller ; its fpecific gravity, which reaches only from 2,6 to 2,7, makes me judge it to be very different from them > its colour is pale bluiih red ; its tex- ture nearly granular, and generally cryfta- Jized in hexangular prifms ; it lofes its colour in a ftrong heat, but does not melt per fey though with borax it gives a colourlefs glafs ; its cornpofition has not yet been examined. SPECIES VIII. Siliceous Earth united to T'T of its weight of Calcareous Earth^ ftilllefs of Magncfta, 'with an exceeding fmall Proportion of Iron, Cop- per, and Sparry Acid. Chryfoprajinm. It is of an apple green colour, and femi- tranfparent; it has never been found cry- ftalized . 122 Elements of Mineralogy* ftalized ; it is much harder than green fluors or green quartz. When diftilled, a little of its Earth fub- limes ; it lofes its tranfparency and colour in fire, but does not melt per fe. Mr. Achard found 100 parts of it to con- tain 95 of filiceous Earth, 1,7 of calcareous Earth, 1,2 of magnefia, 0,4 of iron, and o?(5 of copper. SPECIES IX. Siliceous Earth intimately mixed 'with blue mar- tial Fluor ) and a Jmall Proportion of Gyp- fum. Lapis Lazuli. The colour of this fione is a beautiful opake blue, which varies a little in intenfity, and is generally fprinkled over with yellow, bright, pyritaceous fpecks or ftreaks : it oh- ftinately retains its colour in a ftrong heat, which diftinguifhes it from other blue ftones : it is of an equable or very fine granular texture, and takes a beautiful poliih : its fpecific gravity is 3,054, If powdered and not calcined, it effer- vefces very flightly with acids, but if cal- cined^ Siliceous Genus. 123 cined, it does not effervefce, but becomes ge- latinous. In a ftrong fire it melts ferfe into a whitijh glafs. This ftone has been examined by Mr. Margraaf only with a view of finding whe- ther it contained copper. He found none, but only calcareous Earth, gypfum, iron, and filex. Mr. Rinman lately found it to contain the fparry acid. SPECIES X. Jade. Jade is found in fcattered maffes like peb- bles, femi-tranfparent, of a greafy look, and exceeding hard : its colour is either white, grey, olive, green, or yellowiih : its fpecific gravity from 2,97 to 3,389. According to Mr. Saiiffure* it is fcarcely foluble in acids, at leaft without particular management, and alfo infufible in fire. However, he feems to have paraded iron from it. May it not be a compound of filex and jnagnefia ? SPECIES XI, 124 Elements of Mineralogy, SPECIES XL Siliceous Earth intimately mixed and partly united with 0,209 °f its weight of Argil t, o, 1 64 of its 'weight of ponderous Earth, and 0,12 of its weight of Magnefia. Felt-fpar9 Spathum Pyromachum, Rhombic Quartz, ^uartzum Spathofum^ Spat hum Durum, Petunfe. This ftone, which Is generally opake, is found of all colours, white, red, yellow, brown, green, violet, or iridefcent ; fome- tirnes cryftalized in rhombic, cubic, or pa- rallelipedal forms, and often amorphous : its texture clofe but lamellar, and breaks like fpar : its fpecific gravity is from 2,4 to 2,6, and Mr. Gerhard fays he found it even 3,5; but it was then probably loaded with metallic particles : it is harder than fluors, but not fa as quartz. It melts per fe more quickly and perfectly than fluors, into a whitifh glafs, and doe& .not, like them, attack the crucibles. Borax and microcofmic fait entirely diflblve it with- out effervefcence, but it does not eafily enter into fixed alkalis. When cryftalized, it decrepitates in a moderate heata otherwife not* it Siliceous Genus. 125 It never conftitutes veins or ftrata, but is either found in loofe mafies at moft 2 inches long, or mixed with fand or clay, or imbo- died in other ftones, as granites, &c. 100 parts of the white contain about 67 of filiceous Earth, 14 of argillaceous, if of ponderous, and 8 of magnifia. The fpecific gravity of the fpecimen I tried was 2,542, Labrador Jlone is of this fpecies ; it reflects the colours of the rainbow, is fomewhat fofter than common felt-fpar, and is found in pretty large pieces, generally of a dark grey colour : its fpecific gravity is 2,755. Felt-fpar is undoubtedly the ftone which the Saxons ufe as petunfe in their porcelain manufactories. 3 Berlin Befchaftig. p. 471;. SPECIES XII. Siliceous Zeolyte. This differs from that defcribed under the argillaceous genus only in this, that it gives fire with fteel. It is white, and found at 3 Bergm. 224. It is very rare. SPECIES XIII. 1 26 Elements of Mineralogy. SPECIES XIII. Siliceous Earth imperfectly united to about 0,7 of its weight of Argill^ and -1 of its 'weight of Calcareous Earth, without Iron. Vefuvian Garnet. It is improperly called a garnet, as it con- tains no iron, and it differs from zeolyte in containing no water, and alfo in texture and hardnefs : its colour is white, fometimes opake and fometimes tranfparent, and very hard : it is difficultly acted on by any of the fluxes. According to Mr. Bergman, it contains 55 per cent, of filiceous Earth, 39 of argill, and 6 of calcareous Earth. SPECIES XIV. Siliceous Earth more or lefs perfectly united to 0,63 of its weight of Argill, about 0,4 of its weight of Calcareous Earth, and from 0,28 to about 0,41 of its weight of dephlo- gifticated Iron. Garnet. When not over-loaded with iron it is tranf- parent, though, from the intenfity of its co- lour, Siliceous Genus. 127 lour, whioh is a bluifh or yellowifli red, its tranfparency is often obfcure, except it be held to a ftrong light : it is generally cry- ftalized in various polygon forms, but it is frequently amorphous : its texture is granu- lar ; its fpecific gravity from 3,6 to 4,188. It melts per fe, though difficultly, into a black flag. Mineral alkali does not attack it fo powerfully as borax or microcofmic fait. < It retains its colour in a ftrong calcining heat. It is often found in fmall grains, imbodied in ftones of the commoner]; kind. 100 parts of it contain, according to Mr. ) 48,3 of filiceous Earth, 30 of argill, 11,6 of calcareous Earth, and 10 of iron. Opake garnets, over-loaded with iron, fcarcely give fire with fteel, are fometimes cryftalized and fometimes amorphous, and either red, yelloxvifh, or blackifh, They af- ford about 20 per cent, of iron. Sometimes they contain tin and even lead, but very rare- ly. 2 Bergm. 106. SPECIES XV. 128 Elements of Mineralogy. SPECIES XV. Siliceous Earth more or lefs perfefJfy united to from 0,46 to 0,83 of its 'weight of Argill* from ~ to 4- of Calcareous Earth, and to i or L. of femtphlogiflicated Calx of Iron, and from TTg- to TTT of Magnefta. Schoerl. Its diftinguifhing properties are, ift< either a fparry or femi- vitrified appearance, like an enamel or a flag ; 2d' a filamentous or fcaly texture, which diftinguifhes it from garnets ; the filaments either feparate from each other, or conjoined and plated; 3d* fufibility per fe in a moderate heat ; 4th' a fpecific gravity from 3, to 3,6, rarely 4,000, and only when load- ed with iron ; 5th its hardnefs nearly as that of cryftal. I. VARIETY. Tranfparent. This is always cryftalized in fome poly- gon form : its texture obfcurely fparry : its colour brown, reddifh brown, greenifh or yellowifh brown, or violet : its fpecific gra- vity from 3, ~to 3,6. Siliceous Genus. 129 A reddlfh brown, prifmatic fhoerl of this fort, from Ve/iivius, contained, according to Mr. Bergman, 48 per cent, of filiceous Earth, 40 of argill, 5 of calcareous, I of magne- fia, and 5 of iron* The ufual fluxes affedt this fpecies, as they do the foregoing. The filamentous fort refembles afbeftos, and differs externally only in tranfparency and breaking with an even furface. II. VARIETY. Opake. Thefe are of all colours, white, black, red, brown, greenifh, and violet ; the filaments are conjoined and parallel, or diverge, as from a common center. Thofe of a fcaly or fparry appearance are generally greenifh or black, and are called Hornblende. i hey are frequently cryftalized in regular forms, and often fo foft as to be fcraped with a knife. 100 grains of the black cryftalized fort from Albano, afforded Mr. Bergman 58 of filex, 27 of argill, 5 of calcareous Earth, i of magnefia, and 5 of iron. 3 Bergm. 207. Other forts have afforded 50 per cent, of fili- K ceous Elements of Mineralogy. ceous Earth, 30 of argill, i or 2 of mag* nefia, and 18 or 20 of iron. The white fort probably contains lefs iron. All thefe forts become reddifh by calcina- tion. SPECIES XVI. Siliceous Earth imperfectly united with 0,34 of its weight of Calcareous Earth, 0,107 °f its weight of Argill, 0,08 of Magnejiar 0,026 of Irony and about 0,048 of Water. Bar Shoerl, Stangen Shoerl of the Germans. This was lately found in the Carpathian Mountains by Mr. Fichtel, imbodied in lime- ftone, and cryftalized in prifms : it flightly efFervefces with acids. According to Mr. Bindheim, 100 parts of it contain 6i:6 of filiceous Earth, 21,6 of calcareous Earth, 6,6 of argill, 5 of mag- nefia, 1,6 of iron, and 3 of water. 3 Schrift. Naturforfcb. Freunde^ p. 452. SPECIES XVII, Siliceous Genus. 131 SPECIES XV1L Siliceous Earth imperfeflfy united 'with from 1,05 to 1,47 of its weight of Argill, from 0,3 to 0,4 of its weight of mild Calcareous Earthy and from 0,15/0 0,243 °f*ts wn&bt of Iron* Tourmaline. Tourmaline has hitherto been found only in Ceylon^ Brazil^ and the Tyrol. A fpecimen of each has had the advantage of having been particularly examined by Mr. Bergman. That of Ceylon is of a dark brown, or yellowifh colour, its fpecific gravity 3,065, or, 3,295; that of Brazil is green, blue, red, or yellow, and its fpecific gravity 3,075 or 3,180 ; that of Tyrol, by refle&ed light, is of a blackilh brown, but by refrafted light, yellowifh, or in thin pieces, green; its fpecific gravity 3,050 ; moftiy Ciyftalized in polygon prifms, but fometimes amorphous. The thickell parts are opake : the thin more or lefs tranf- parent. All are electric when heated to about 200 of Fahrenheit. Their texture is lamellar, and their furface has a glaflfy appearance. In fire none of them decrepitate ; but thofe of Ceylon and Tyrol melt perfe into a K 2 black Elements of Mineralogy. black frothy flag. That of Brazil forms otl* ly a brittle fcoria. Of the ufual fluxes, bo- rax diflblves them beft, microcofmic fait and mineral alkali partially. The proportion of their conftituent prin- ciples is thus exhibited by Mr Bergman : Tourmaline of TyroL Argill, - 42 Silex, ~ 40 Calcareous Earth, - 12 Iron, - 6 100 Tourmaline of Ceylon. Argill, - 39 Silex, - 37 Calcareous Earth, - 15 Iron, - 9 IOQ Tourmaline of Brazil. Argill, - 50 Silex, - - 34 Calcareous Earth, - - 1 1 Iron, - - *• 5 100 SPECIES XVIII. Siliceous Genus. 133 SPECIES XVIII. Siliceous Earth mixed 0,04 of Magnejiai and 0,5 of Iron. Bafaltes, Trapp of the Swedes^ Saxum Dane- morenfe. A dark grey or black ftone, generally in- verted with a ferruginous cruft and cryfta- lized in opake triangular or polyangular columns, is called bafaltes ; that which is amorphous, or breaks in large, thick, fquare pieces, is called trapp. Their conftituent principles, and relation to acids and fluxes, are exaftly the fame. The texture of this ilone is either coarfe, rough, and diftinft, or fine and indifcernable. This latter fort is often reddifh ; it is always opake, and moul- ders by expofure to the air ; fome fpecimens give fire with fteel very difficultly, though it is always very compact ; fometimes it is fprinkled over with a few minute fhining par- ticles : its fpecific gravity is 3,000. When heated red hot, and quenched in water, it becomes by degrees of a reddifh brown colour : it melts perfe in a ftrong heat into a compaft flag. Borax alfo diflblves it in fufion, but mineral alkali not intirely. K 3 According 134 Elements of Mineralogy. According to Mr. Bergman, 100 parts of the bafaltes contain 52 of filiceous Earth, 15 of argill, 8 of calcareous, 2 of magnefia, and 25 of iron. 3 Bergm. 213. And with this Mr. Meyer very nearly agrees. » 14^- turfor/h. 5. SPECIES XIX. Siliceous Earth mixed 'with 0,69 of its weight of Argill 9 and 0,41 of its weight of Iron in a femiphlogifticatedjtate* Rowly Ragg. This ftone is alfo of a duiky or dark grey colour, with numerous minute fhining cry- ftals ; its texture granular ; by expofure to the air it acquires an ochry cruft; its fpecific gravity 2,748, Heated in an open fire it becomes mag- netic. In a ftrong heat it melts perfe, but more difficultly than bafaltes. According to Dr. Withering *s analyfis, 100 parts of it contain 47,5 of filiceous Earth, 32,5 of argill, and 20 of iron. XX. Siliceous Genus. 135 SPECIES XX. S/liceous Earth more or lefs perfectly united to from ~ to -j?- of its weight of Argill^ 0,3 or 0,4 of Its iveight of Iron, and a fmall proportion of pure Calcareous Earth9 but this isfometimes 'wanting. Lava. By Lava I underftand the immediate pro- duct of liquefaction or vitrification by vol- canic fire, which mould carefully be diftin- guifhed from the fubfequent productions af- fected by the water either in a liquid or fluid ftate, which generally is ejected at the fame time. All lavas are more or lefs magnetic, give fire with fteel, are of a granular texture, and fufible per Je. Moft are decompofable by long expofure to the air, fooner or later, ac- cording to the proportion of iron and calca- reous Earth, and according as they were more or lefs perfectly melted or vitrified. Mr. Bergman, in his elaborate treatife on volcanic products, diftinguifhes three varieties of lava ; the cellular or frothy, the compact, and the vitreous. K 4 I. VARIETY, 136 Elements of Mineralogy, I. VARIETY. Cellular Lavas. Thefe underwent only the firft and loweft degree of fufion, being juft mollified and heated fufficiently to expell the fixed air con- tained in the argillaceous particles ; hence they abound in fmall cavities arifmg from the expaniion of that air after it had recovered its elailic ftate. Their fpecific gravity is vari- ous : fome are fo light, by reafon of their in- ternal cavities, as to float for fome time on water, and hence, have been miftaken for pumice ftones, but they differ from thefe in this, that their texture is never filamentous. Their colour is black, grey, brown, or reddim brown, and their cavities are often fil-r led with cryftalizations. Of this fort is the black cellular mill-ftonQ of the Rhine. Thefe ftones contain from 45 to 50 per cent, of filex, and from 15 to 20 per cent, of iron, 4 or 5 per cent of pure calcareous Earth, a&d the remainder argill, II. VARIETY, Siliceous Genus. 137 II. VARIETY* Compact Lavas. Thefe have undergone the ad or more per- fect degree of fufion, yet they are not entirely dcftitute of cavities which contain finer cry- ftals, or pieces more perfectly vitrified ; their colour is black or brown ; their fracture is ftill obfcure, and not glafly, as the ftones them- felves are opake : if not cracked, they give a clear found when ftruck. The proportion and quality of their con- ftituent parts are the fame as in the foregoing variety. The ufual fluxes attack them with difficulty, and microcofmic fait has fcarce any power over them. III. VARIETY, Vitreous Lavas. Thefe have beert more completely melted, and form vitrifaftions of different colours^ generally black or afh-coloured, rarely blue or greenifh, A fpecimen of this glafs, examined by- Mr. Bergman, afforded 49 per cent, of filexf 35 138 Elements of Mineralogy. 35 of argill, 4 of pure calcareous Earth, and 12 of iron. Another fpecimen from the Lipari I/lands afforded 69 of filex, 22 of argill, and 9 of iron. This muft have been expofed to a very ftrong heat, for they melt very difficultly perje. The black Agate of Iceland, (Lapis oljidla- MIIS, Piedra de Galmac_o) is of this fort, and its principles and their proportions nearly the fame. The harder fort of pitch ftones, already de- fcribed, which give fire with fteel, belong to this fpecies. Mr. SauJJure has ingenioufly imitated all thefe fpecies of lava, by melting more or lefs perfeftly the compound argillaceous fpecies into which hornftone enters as the moft copi- ous ingredient, and which he therefore calls Hornrock) Roche de corne^ and which are al- ready defcribed. Voyage dans les Alpes, p. 127. And hence he juftly conjedhires that this ftone, marl, and the fchifti (Species 6, 7, and 8 of the Argillaceous Genus i are the principal materials of lava, Ibid-> 131, 132. SPECIES XXI, Siliceous Genus. 139 SPECIES XXI. Siliceous Eartb mixed 'with o, 1 1 or o, 1 7 of its 'weight of Magnefia, and a little of Calcareous Earth. Pumice-ftoney Pierre Ponce, Bimftein. This feems rather a volcanic ejection than a volcanic product; its colour is grey, white, reddifh brown, or black : it is hard, rough, and porous, and confifls of {lender fibres pa- rallel to each other ; very light, for it fwims on water, and difficultly gives fire with fteel. It feems to have originally been an afbeftos decompofed by the action of fire. 100 parts of it contain, according to Mr. Bergman, from 6 to 15 of magnefia, with a very fmall proportion of calcareous Earth, the remainder filex. SPECIES XXII. Siliceous Earth mixed 'with lefs than its own weight of Magnejia and Iron. Martial Muriatic Spar. Mr. Monnct, a Mineralogift of considerable note, lately dilcovered this ftone at St. Ma- rie aux Mines, and called ilfifoKtes} but as a very 140 Elements of Mineralogy. very different compound is generally denoted by this name, I have called it martial muriatic fpar, a name which agrees better with its properties. It is of a hard, folid, and fparry texture ; of a grey, ochry, dull colour, but internally bright : it gives fire with fteel, yet effervefces with acids. In a ftrong heat it grows brown, but at laft melts perfe. 100 parts of it contain 50 of filex, the remainder mild magnefia and iron, but in what proportion is not mentioned, 13 Roz* Suppl. 416. SPECIES XXIII. Siliceous Earth intimately mixed 'with j. of its weight of mild Calcareous Earth. Turky Stone> Cos Turcica, This is of a dull white colour, and uneven texture ; fome parts appearing more compaft than others, fo that it is in fome meafure ihattery : it hardens with oil ; its fpecific gravity is 2,598 ; it gives fire with fteel, yet effervefces with acids. Siliceous Genus. I found loo parts of it to contain 25 of mild calcareous Earth, and no iron. There probably are two forts of ftone known by this name, as Mr. Wallerius affirms that which he defcribes, neither to give fire with fteel, nor effervefce with acids. SPECIES XXIV. Siliceous Earth mixed ivitb mild Calcareous Earth and Iron. Ragg-ftonc. Its colour is grey; its texture obfcurely la- minar, but the laminae confift of a congeries of grains of a quartzy appearance, coarfe and rough; its fpecific gravity is 2,729; it effervefces with acids, and gives fire with fteel. I found it to contain a portion of cal- careous Earth, and a fmall proportion of iron. It is ufed as a whetftone. SPECIES XXV. Arenaceous Quartz confolidated by a fmalkr proportion of Calcareous Earthy or Argill, andftill a fmaller of Iron. Siliceous Grity Sandjlone, Free/lone, Cos Are- narius, Grais. Under this fpecies I comprehend only fuch as ftrike fire with fteel, and when pounded, 142 Elements of Mineralogy. pounded, form a fand rather than a pow- der. I, VARIETY. Grit 'with a Calcareous Cement > Quadrum. A ftone of this fort hath been already de- fcribed under the calcareous genus. When it contains about 50 per cent, or more of filex it belongs to this fpeciesj it commonly contains alfo a fmall proportion of argill and iron ; it hardens by expofure to the air, and then ftrikes fire with fteel, and effervefces flightly with acids : it is fometimes cryftalized in rhom- boids, as at Fontainb'eau. 100 parts of this contain, by the experiments of Mr. LaJJone, 62,5 of filex and 37,5 of mild calcareous Earth. Mem. Par. 1777, p. 43. The Saxum margdriticum of Linneus be- longs alfo to this fpecies : it confifts of quartz in a calcareous cement. II. VARIETY. With an Argillaceous Cement. Thefe do not effervefce with acids, but they ftrike fire with fteel, though fome forts are too foft to do io until expofed for fome time to the air. The free-ftone from Keredge^ near Mac- clesfield) which is of a clofe grain, is of this fpecies. Its fpecific gravity is 2,544. So Siliceous Genus: 143 So alfo that of Bro in Stafford/hire* which is fo perfect a fand-ftone that its fpe- cific gravity is only 2,397; an<* t'ie whitnli grey freeftone from Uttoxeter. All thefe con- tain a little of iron. Stones of this fpecies are ufed for whetting tools, and for filtring water, and in fome countries as flates. The principal diftinclion among them arifes from the finenefs or coarfe- nefs of their grain and texture. Their colours are various, receiving different tinges from iron. SPECIES XXVI. Siliceous Sand confolidated by femipblog ifticatect Calx of Iron. This ftone does not fall into fand when powdered, and in this refpedt differs from the foregoing. It is generally of a brown or black colour, but grows reddifh or yellowifh, and moulders by expofure to the air j its fpe- cific gravity is from 2,8 to 3,6 ; it gives fire with fteel, and does not effervefce with acids, unlefs it contains teftaceous particles, as it frequently does : it is even often covered with fliells. The agglutinating power of folutions of iron has been fhewn in an ingenious paper in the T44 Elements of Mineralogy* the Philofophical Tranfadions for 17791 p^ 35, by Mr. Ed-ward King, who found a ftony concretion of this fort round iron, which had been long buried in the fea. Mr. Gadd, in the Swedifh Memoirs for 1770, relates, that Mr. Rinman had found a fimilar concretion round an old anchor that had long been depoiited in the fea. He alfo adds, from his own experiments, that dephlo- gifticated calces of iron, and particularly folutions made by the mineral acids, have not the fame binding power, but, on the contrary, make loofe concretions, as Dr. Higgim has alfo fhewn in a late very ufeful treatife on cements. To this fpecies may be added the blacky heavy* glojfy Quartz of Cronjhd* § 53, which he fays is found in the mine of 6/J/i in Su- dermanland, and contains a large proportion of iron. Compound Species in nvhich the Siliceous Genut predominates. SPECIES I. Compounds of the different Species of the Sill-, oeous Genus Shoerly and Garnet. Of confiderable hardnefs and weight, with large fpots of red, green, and yellow ; the garnet red. the fhoerl green, and the jade yel- low. Sauffure, p. 107. V. VARIETY. Quartz* Felt-fpar, and Shoerly Granite. Thefe are fo well adapted to each other, that, as Mr. SauJJure well remarks, they could not have been fo compa&ed by an ac- cidental mixture of mafles previoufly formed, but muft have cryftalized together.- It may be feen among the paving ftones of London. The quartz is white, the fhoerl black or vio- let, and the felt-fpar reddifh. VI. VARIETY. Pudding/lone^ Breccias. Stones which confift of a filiceous ground or cement, (commonly petro-filex, jafper, or filiceous grit) in which pebbles of filex or agate are interfperfed j if thefe be round or oval, are called pudding ftones \ if angular* breccias. Of the coarfer forts mill-ftones are .often made. Mem. Par. 1758. VARIETY. Siliceous Genus. 147 VII. VARIETY. Coral Stone. This is an aggregate of onyx, fardonyx, rnelian amethyft, and quartz. SPECIES II. Compounds of the Siliceous with the Calcareous Species. I. VARIETY. Quartz and Spar." Diftinft grains of each compared together ; the quartz generally white and femi-tranfpa- rent ; the fpar of a brownifh yellow. Sauf* fur 6) 104* SPECIES III. Compounds of the Siliceous and Earytit Species* SPECIES IV. Compound of the Siliceous and Muriatic Species. I. VARIETY. Quartz^ Felt-fpar, and Serpentine. II. VARIETY. Shoerl and Soap-rock. Compared of diflinft mafles of each, SauJJiire 104. The foap«rock is green, and ,L 2 the 14$ Elements of Mineralogy. the fhoerl black. It gives fire with fteel, when the fhoerl is ftruck. III. VARIETY. Quartz and Steatites. Obferved alfo by Mr. Sauffure^ the quartz white, and the fteatites green. IV. VARIETY. QtartZy Shoerl, and Steatites. The fteatites inclofed in the quartz in the form of black kernels. SPECIES V. Compounds of the Siliceousy and Argillaceous Species. I. VARIETY. Quartz and Mica. Stellften of the Swedes. Cranitello. It ftrikes fire with fteel, and does not eafily melt; and hence ufed for furnaces, &c. When the mica abounds it is of a lamellar texture, its colour is generally grey, or green ; the mixture of mica prevents the filex or quartz Siliceous Genus. 149 quartz from cracking or fplitingj and hence its infufibility and ufe in furnaces* II. VARIETY. Feltfpar and Mica> Granltone. This ftone is mentioned by Ferber, in his letters from Italy, p, 1 1 8. A ftone of this fort which moulders by expofures to the air, is found in Finland, and is faid to contain fometimes faltpetre, and fometimes common fait, it is there called Rapakivi^ I Linne von Gmelin, 621. III. VARIETY. Quartz and Horn-Jlonc. In fmall diftinft grains compacted together, this is found plentifully in the mountain of Penmaumaure in Wales. It exhales an earthy fmell, gives fire with fteel, and is of a thick lamellar texture: its fpecific gravity is 2,811. the quartz is white, and the horn-ftone black, which gives the ftone a bluifh appearance. IV. VARIETY. l^itartz, Feltfpar^ and Mica^ or Quartz, Shocrl and Mica. Granite^ Moor-Jione. This ftone confifts of diftin<3 mafles of each, firmly compacted together, their pro- L 3 portion 150 Elements of Mineralogy, portion and fize are extremely variable* as well as their colour. The three firft confti^ tute the hardeft fort of the granite, and moft anciently known ; that into which the fhoerl enters, is more fubjecT: to decompofition ; it never has any particular texture, but confifts of enormous fhapelefs mafles, of great hard- nefs. In the finer granites, the quartz is tranfpa- rent, in others generally white or grey, violet or brown ; the feltfpar, white, yellow, red, green, or black, it is generally the moft copi- ous ingredient. The mica is alfo grey, brown, yellow, green, red, violet or black, and is commonly leaft copious. The fhoerl is gene- rally black, and abounds in the granites that contain it. Hence the colour of granites chiefly depends of the feltfparor fhoerl. The red granites confift commonly of white quartz, red feltfpar, and grey mica. The grey of white quartz, grey or violet feltfpar, and black mica. The black commonly con- tain fhoerl, inftead of feltfpar. The green commonly contain greenifh quartz. If granite be expofed to a blow-pipe, its different concretions fepirate from each other. In a crucible, Mr. Gerhard found the feltfpar melted into a tranfparent glafs ; under it the jnica lay in the form of a black flagg, and the Siliceous Genus. 151 the quartz remained unaltered; but when all three are powdered and mixed, it melts fomewhat better, yet ftill the quartz may be diftinguifhed by the help of a lens Gerh. Gefch. §51. This well explains why fmall white grains are frequently found in lavas. Mr. Jy Arcefs experiments coincide with this, and alfo thofe of Mr. Sauffurc^ p. 124. V. VARIETY. Quart %i Fdtfpar^ Shoerl and Mica. This is alfo a fort of granite obferved by Mr. Sauffiire in the Alps. VI. VARIETY. Jade> Shoerl, and Mica. A fort of granite obferved by Mr. Sauffwe. VII. VARIETY. Quartz, Garnet^ and Mica* Norkat Murkfteln. This is either grey or reddifh, and ufed for mill- (tones, the mica is foon wore off, VIII. VARIETY, Porphyry. Under this name I comprehend with Mr. all thofe ftones which in a compact L 4 fiUceous 152 Elements of Mineralogy. filiceous ground ( generally jafper, chert, fhoerl, or lava) contain either feltfpar, quartz, fhoerl, mica, ferpentine, or other fpecies of flone in a cry ft aline form. When its ground is jafper it is hard. It is commonly either red, purple, grey, green, or black, according to the ground. The red commonly contains feltfpar in fmall white dots or fpecks, and often together with thefe black fpots of fhoerl. The green is either a jafper or fhoerl, with fpots pf quartz or fhoerl. Sometimes a por- phyry of one colour contains a fragment of a porphyry of another colour; the green are often magnetic. Thofe that have chert for their ground, are fufible per fe. SPECIES VI. Compounds of the Siliceous, and various Genera, I. VARIETY. * 1. §>uartz9 Mica, ^nd Serpentine, 2, Quartz, Mica, and Steatites, 3. ^yartz^ Mica, andShoerl> together 'with Serpentine or Steatites, or Soap-rock. 4. Quartz, Felt-fpar, Mica> and Serpen-* All Siliceous Genus: 153 All thefe ftones are called Gneifs> and are generally of a lamellar texture. II. VARIETY, AmygdaloideS) Mandelfteln of fame* This confifts of a chert or jafper ground, in which fragments of calcareous fpar, and ferpentine, of an oval form, are contained* III. VARIETY. Vciriolite. This is faid to be a compound of all forts of ftones, included in a ground of ferpentine. Ferber, Italy, p. 120. IV. VARIETY. Metallic Stone of Linn#us and Born. It confifts of Quartz, clay, and fteatitesf d is of different degrees of hardnefs, fome- times the fteatites is wanting, fometimes felt- fpar is found in it. V. VARIETY. §>uartZi Spar, and Mica. Saxwn Angermanni- film of IJtw&w, CHAP. 154 Elements of Mineralogy. CHAP. IX. Of Vegetable and Animal Earths. Vegetable Earth has been thought by many to be of a peculiar nature, fpecifically different from every other ; but late experiments have fully fhewn. ift\ That vegetables contain but a very fmall proportion of Earth of any fort, and that far the greater part of their fubftance confifts of water, fixed air, and inflammable air in a concrete ftate, as remote principles, a fmall proportion of fixed alkali which pro- bably is neutralized by vegetable acids, and a few other neutral falts. Thus according to the lateft experiments, 33 pound of oak afford only 3 drachms of afhes. Memoirs of Stockholm, 1781. 2dly> That the Earth of vegetables is for the greater part, either calcareous, or a mix- ture of all forts of Earths, and fometimes of the calces of iron and manganefe, in vari- ous proportions, according to the fpecies of the vegetable. Thus Mr. Bergman found the afhes of fome vegetables to contain calcareous, ponderous, muriatic, argillaceous, and even filiceous Earth ; and hence afhes effervefce with acids, and are fufible perfe, even after perfeft Vegetable and Animal Earths. 155 perfect lixiviation. He alfo found fometimes animal Earth, (that is phofphoric felenite,) in afhes. The Earth remaining after the putrefac- tion of vegetables, is exactly of the fame nature. Sch § i 72. Mr. Morveau found the afhes of fome vegetables to contain 97,5 per cent. of calcareous Earth, the remainder magnefia. Mr. Berniardy Mr. D' Arcet^ and Mr. Achard, have had nearly the fame refults. 1 9 Roz. 52. The neutral falts moft ufually found in afhes, are tartar vitriolate, glauber's fait, common fait, digeftive fait, and felenite, alfo hepar fulphuris ; according to Model a pound of rhubarb contains an ounce and a half of felenite. Hence we fee why clay is fo unfavourable to vegetation, and how calcareous Earth i$ introduced into the bodies of animals. Animal Earth? is obtained either from the {hells of fifh, or from thofe of eggs, or from pearls, or from the bones, horns, claws of Jand animals, or from the {kins of i That obtained from the fhells of fifh and from thofe of eggs, is found by repeated expe- riments to be purely calcareous ; only oyfter {hells difcover fome feeble veftiges of felenite. Bergm, on Scheffer, § 173, that obtained from Elements of Mineralogy. from bones, horns, claws, teeth, &c. was found by Mr. Gabn, to be a calcareous Earth united to the phofphoric acid ; hence the folution of bones in the mineral acids can never be neutralized, a circumftance which puzzled all preceeding chymifts, but which is now perfectly underftood, as fuch folution is in facl: only the folution of a neutral fait if the bones be diflblved in the nitrous or marine acids, or a decompofition of a neu- tral fait, if the vitriolic acid be ufed as a folvent ; in either cafe a free unfaturated acid muft be found. However fome bones con- tain an excefs of phofphoric acid, and fome an excefs of Earth, as ivory, whence fome have imagined this latter to contain a pecu- liar Earth. Some late and accurate experi- ments relating to the proportion of phofpho- ric acid in bones by Mr. Berniard, may be feen in Rozier*s journal, for 1781, p. 280, 1782, p. 43. The phofphoric acid is feparated from this Earth by calcining the bones to whitenefs then diffolving them in nitrous acid, and precipitating the calcareous Earth by the concentrated acid of vitriol. A felenite is thus obtained (decompofable either by calci- nation with charcoal, or by boiling in a folution of mild fixed alkali,) and the phof- phoric acid remains in the liquor. APPENDIX Diamond. 157 APPENDIX I. Of Diamond and Plumbago. Thefe fubftances cannot well be arranged under any of the clafles of minerals ; not under that of Earths as they contain no Earth, nor under that of inflammables, as their inflammability commences in fuch high degrees of heat, and is fo gradual that it can fcarcely be remarked but by its effecl: in dimi- niming the weight of thefe fubftances after a long expofure to fire ; fo that they differ intirely from all other inflammables, whence I think it convenient to treat of them a part. Diamond. Diamond is always tranfparent, and moftly colourlefs, but fometimes tinged, yellow, reddiih, green, blue, or brown; it is fome- times externally, but always internally bright ; it is generally cryftalized in oclohedral cryftals , but fometimes found in round mafles : its texture is lamellar. It ftrikes fire with fteel, cuts the hardeft cryftals, and even rubies, being the hardeft of all bodies : its fpecific gravity is from 3,5 to 3,66. No 158 Elements of Mineralogy, No acid has any effeft on it, except the vitriolic; if diamond powder be triturated with this acid, and evaporated nearly to drynefs, the acid grows black and depofits pellicles, which burn and are almoft entirely con- fumed. In a heat fomewhat greater than that in which lilver melts, diamond is intirely vola- tilized and confumed ; it even produces a flight flame and diminimes common air, juft as phlogiftic fubftances do, and leaves a foot, fo that the extraordinary conjecture of bir Ifaac Newton, of its being an inflammable fubftance coagulated is fully confirmed. Of the ufual fluxes, only borax and microcofmic fait have any effect on it. It is found in Golconda, Vifapour, Bengal, the ifland of Borneo, and Brazil. The nature of cubic diamonds has notyet been examined. Plumbago, Riifsbley, of the German's, Blyertz* of the Swedes. This fubflance is externally black, but bluifh white and fhining like a metal when frefh cut : its texture is micaceous and fcaly, yet granular. It is ufed for pencils. It Of Plumbago. 159 It is too foft to ftrike fire with fteel : its fpecific gravity is from 1,987, to 2,267. It is infoluble in the mineral acids. In a ftrong heat and open fire it is wholly volatile, leaving only a little iron, which feems to be only accidentally found in it, and a few grains of {ilex. The ufual fluxes do not effedt its fufion. It is decompofed by detonnation with ni- tre, in a red hot crucible. According to Mr. Scbeele, who firft dif- covered the nature of this mineral, i part plumbago requires 10 of nitre to decompofe it, whereas i part charcoal requires but 5 of nitre : hence it contains twice as much phlo- gifton as charcoal does. By receiving the air arifingfrom its decompofition in a bladder, he found ~ of that air to be abforbable by lime water, and confequently to be fixed air, and in the remainder a candle would burn : but as nitre itfelf might afford fixed air by com- buftion, to get rid of all objections, he de- compofed plumbago by fubliming and re- ducing the arfenical acid, after mixing it with plumbago ; and thus alfo he obtained fixe4 air. It is probable that 100 grains of it con- tain 160 Elements of Mineralogy. tain 33 of aerial acid, and 67 of phlogifton j for 100 grains of nitre contain about 33 of real nitrous acid. This is decompofed when it receives as much acid as is neceflary to convert it into nitrous air, or a little more- Now 33 grains of nitrous acid are converted into nitrous air by about 6,7 grains of phlo- gifton : then 1000 grains of nitre require for their decompofition 67 of phlogifton : and fince 100 grains of plumbago decompofe 1000 of nitre, they muft contain 67 of phlo- gifton. APPENDIX IF. Of the general Examination and Analyjis of Earths and Stones. SECTION I. Of the Examination of Earths. When Earths are well dried and feparated from every vifible heterogeneity, a portion of them mould be weighed and diftilled in a glafs retort, until the bottom begins to grow red hot. In fome cafes it may be proper to receive the air that arifes, in a pneumatic apparatus ; in ail it will be proper to examine what diftills over, or fublimes, whether it be acid or al- kaline, with" paper tinged blue by litmus, and partly reddened by diftilled vinegar : if the blue Analyfis of Earths and Stones*. 1 61 blue be reddened, an acid exifts in the diftil- led liquid ; if the red be effaced, and the blue reftored, a volatile alkali is the caufe of it : if the liquor precipitates lime water, but does not precipitate nitrous felenite, then it con- tains fixed air : if it precipitates alfo nitrous felenite, it contains the vitriolic acid : if it contains the marine acid, it will not precipi- tate nitrous felenite, but it will the nitrous folution of filver: The lofs of weight of the refiduum in the retort, and the weight of the water in the receiver, will {hew the pro- portion of the volatile ingredients. \ Another portion fhould be digefted in about 6 or 8 times its weight of pure water, and the properties of that water examined, to find whether the Earth contains neutral falts. Here the method given by Mr. Bergman in his analyfis of mineral waters, fhould be fol- lowed. SECTION II. Of the general Examination of Stones. Their fpecific gravity fhould firft be exa- mined; alfo their hardnefs ; whether they will ftrike fire with fteel, or can be fcratched by the nail, or only by cryftal or ftones of ftill greater hardnefs 3 alfo their texture, perviouf- M nefs 1 62 Elements of Mineralogy. nefs to light, and whether they be manifeftly homogenous or compound fpecies, &c. 2dl In fome cafes one fhould try whether they imbibe water, or whether water can ex- trait any thing from them by ebullition or digeftion. 3d- Whether they are foluble in, or effer- vefce with acids, before or after pulveriza- tion; or whether decompofable by boiling in oil of tartar, &c. as gypfums and ponderous fpars are. 4th- Whether they detonnate with nitre. 5th' Whether they yield the fparry acid by diftillation with oil of vitriol, or a volatile alkali, by diftilling them with fait of tartar. 6th- Whether they are fufible per fe with a blow-pipe, and how they are affefted by mineral alkali, borax, and microcofmic fait ; and whether they decrepitate, when gradually heated. 7th* Stones that melt perfe with the blow- pipe a^e certainly compound, and contain at leaft 3 fpecies of Earth, of which the calca- reous is probably one ; and if they give fire with fteel, the filiceous is probably another. SECTION III. Anal)fis of Earths and Stones, 163 SECTION III. Of the Analyfis of Earths and Stones. The beft general folvent for Stones or Earths feems to me to be Aqua Regia, com- pofed of two parts nitrous, and one of marine acid : if the ftone or Earth effervefees ftrongly with acids, no other preparation is requifite than a feparation of fuch parts as are vifibly heterogenous, and pulverization ; the folution is then eafily performed in a digefting heat, if requifite. The undiffolved refiduum, if purely filiceous, will melt into a tranfparent glafs with about \ its weight of mineral al- kali > if not, it is ftill compounded, and its foluble parts will yield to a reiterated di- geftion. If the ftone does not effervefce, or eafily diffolve in acids, after pulverization and di- geftion, but leaves an infoluble refiduum evidently compound, or but flightly altered, it will require to be pulverized and mixed with twice or thrice its weight of mineral alkali, and to be expofed to a low red heat for one or two hours. I found mica to re- quire a mixture of 4 times its weight of mineral alkali ; after which it is to be fepa- rated from the alkali by lixiviation and filtra- tion, wafliing it with diftilled water until the M 2 water 164 Elements of Mineralogy. water is abfolutely taftelefs and precipitates no metallic folution. The powdered ftone, thus edulcorated, is to be dried by heating it to rednefs, and then weighed, and 100 grains taken for fubfequent experiments : it were better if ftill more were ufed, but the analyfis would be more expen- five. The powder is next to be digefted in 8 or 10 times its weight of aqua regiay in a boil- ing heat in a retort to which a receiver is luted, and the digeftion reiterated as long as any thing appears to be diffolved by frefh portions of the acid. I found mica to require 50 times its weight of aqua regla before it was entirely decompofed, as the acid is fo volatile as very foon to diftill over. Oil of vitriol has the advantage of bearing a greater heat, diflblving barofelenite, and of ading more powerfully on argill than aqua regla ; but a large retort muft be ufed, for, often towards the end it puffs and throws up the Earth or ftone, and carries it into the receiver ; and it does not fufficiently act on calces of iron, if thefe be much dephlogifticated. Spirit of nitre affedu them ftill lefs : hence I often uie oil of vitriol firft, then precipitate by a mild alkali what it has diffolved, and rediflblve the precipitate in aqua regia. A perfect folu- tion Analyfu of Earths and Stones. 165 tion being thus effe&ed, the refiduum is to be well wafhed, and the wafhings added to the foluiion: the refiduum, -well dried and weighed, gives the weight of filiceous Earth in the compound. The folution is next to be examined ; which I will fuppofe to contain the 4 foluble Earths, calcareous, ponderous, magnefia, and argill, and alfo a calx of iron : it always contains an excefs of acid, of which it is in. great meafure deprived by boiling for a con* fiderable time, as both acids are very volatile, and indeed, of the marine none remains but what is combined with the calx of iron, as the nitrous chafes it from the Earths. By get- ting rid of this excefs of acid, lefs alkali will be required for the fucceding precipitation, and lels aerial acid fet loofe which would retain much of the precipitate by re-diflblving it : the folution fhould then be evaporated to about \ a pint. The folution being thus prepared, it is ufual to precipitate the calx of iron from it by the Pruffian alkali ; but to this method I have two objections ; ift< that the ponderous Earth, if any, would alfo be precipitated and confounded in the Pruffian blue ; and 2d< that this precipitation, befides being exceeding flow, feldom fails of leaving fome iron Hill M 3 in 1 66 Elements of Mineralogy. in the folution, as the excefs of the Pruffian alkali, which muft neceflarily be added, to b& certain that all the iron is precipitated, never fails to re-diflblve a portion of the Pruffian blue which thus remains in the liquor, and cannot be got rid off. Hence the method I ufe is as follows : firft, I prepare the Pruffian alkali after the manner of Mr. Bergman, by digefting and boiling a pure 'alkaline folution over Pruffian blue, until the alkali no longer effervefces with acids, nor precipitates a folu- tion of nitrous felenite, or any other Earth, except the barytes : I even make it a little ilronger ; for if it be barely faturated with the tinging matter, it foon fpoils and precipitates Other Earths, the tinging matter evaporating. I next examine how mucih of ,this alkali is neceflary to precipitate i gr. of iron from its folution in dilute vitriolic or marine acid, and I mark this on the label of the bottle that contains the alkali. I now come to the ap* plication, The folution of the earths being weighed I take 100 grains of it, and on thefe I gra- dually pour the Pruffian alkali (a portion of which is alfo previoufly weighed) until all the iron, or ponderous Earth and iron, is pre- cipitated; the weight of the alkali ufed, gives that of the iron contained in 100 grains of the folution, and the quantity contained in rpg I Analyfis of Earths and Stones. 167 100 gr. of the foliation, gives that contained in the whole folution, by the rule of proportion, from which the ponderous Earth, if any be found in fubfequent experiments, is to be dedu£ted. The quantity of iron being thus found, the remainder of the folution is to be preci- pitated by aerated mineral alkali, and then boiled for half an hour to expel a$ much as poffible of the fixed air; by this means the whole of its contents are precipi- tated, and nothing remains in folution, but cubic nitre and a little common fait ; when the precipitate has fettled after one or two days reft, the liquor is to be poured off, and the laft portions taken up with a glafs fyringe. Diftilled water is then to be added to the precipitate and boiled over it, and afterwards poured off and t^ken up uruil it comes of taftlefs. The precipitate being fufficiently dried, is to be re-diffolved in nitrous acid twice, and evaporated to drynefs, then calcined for one hour in a white heat, and laftly treated with about fix or eight times its weight of diflilled vinegar, in a heat of about 60 de- grees, for one or two hours ; by this means the ponderous, calcareous, and magnefia Earths will be extracted and feparated from M 4 the 1 68 Elements of Mineralogy. the argill and calx of iron, which will remain imdiflblved. Of this acetous folution TOO grains fhould be taken and examined with the Pruffian alkali, if any part be precipitated it is pon- derous Earth, and by heating this to rednefs its weight may be known, or ftill better by a previous experiment, determining the quan- tity requifite to precipitate i gr. of acetous barofelenltes, and by the rule of proportion, the quantity of it in the whole folution may be found. The remainder of the acetous folution, is to be evaporated to drynefs, and heated white in a clean polifhed iron crucible for two hours, then weighed and thrown into hot diflilled water, the calcareous Earth, (if any,) will be diffolved in a fufficient quantity of this water, of which an ounce can fcarcely diflblve i gr, fo that frequent affufions of hot water may be requifite; the magnefia will remain undif- folved, and is to be dried and weighed, its weight gives that of the pure calcareous Earth, from which that of the ponderous (if any) is to be deducted; the lime-water may alfo be precipitated by an aerated alkali. Laftly, the argill and calx of iron, which remained undiffolved by the acetous acid, are Analyfis of Earths and Stones. 169 are to be heated {lightly, to prevent their co- hering and reiteratedly boiled in dephlogifti- cated nitrous acid to drynefs, and finally dif- folved in that acid, which will then take up only the argill, which may be precipitated, dried and weighed; though indeed this trou- blefome operation may be unneceflary, as the- weight of the martial part being known by the experiment, with the Pruffian alkali ; that of the argill is known of courfe, when only the two remain. This is even better, as the calx always increafes in weight by thefe ope- rations. Befides this general method fotne others may be ufed in particular cafes. Thus to difcover a fmall proportion of argill* or magnefia^ inafolution of a large quantity of calcareous Earth, cauftic volatile alkali may be applied, which will precipitate the argill or magnefia, if any be, but not the calcareous Earth. Diftillcd vinegar applied to the pre- cipitate,. will difcover whether it be argill or magnefia. A minute portion of calcareous or pon- derous Earthy inafolution of argill or magnefia* may be difcqvered by the vitriolic acid, which precipitates the calcareous and ponderous, the folution ihould be dilute elfe the argili alfo Elements of Mineralogy. alfo would be precipitated. If there be not an excefs of acid, the faccharine acid is ftill a nicer teft of calcareous Earth. 100 gr. of gypfum contains about 32 of calcareous Earth. 100 gr. of barofelenite contains 84 of ponderous Earth. 100 gr. of faccharine fe- oienite contains 45 of calcareous Earth : the infolubility of barofelenite in 500 times its weight of boiling water fufficiently diflin^- guifhes it. From thefe data the quantities are eafily inveftigated. 3dly- A minute proportion of ar gill in a large quantity ofmagnejia, maybe difcovered either by precipitating the whole and treating it with diftilled vinegar, or by heating the folu- tion nearly to ebullition, and adding more aerated magnefia untill the folution is per- fectly neutral, which it never is when argill is contained in it, as this requires an excefs of acid, to keep it in folution. ' By this means the argill is precipitated in the ilate of embryon alum which contains about \ its weight of argill, (or for greater exaclnefs it may be decompofed by boiling it in volatil alkali.) After the precipitation the folution mould be largely diluted, as the Epfom fait, which re- mained in folution while hot, would preci- pitate when cold and mix with the embryon alum. .thlV, Analyfis of Earths and Stones. 171 ^thiy. ^ minute portion of magnefia in a large quantity of argil! is beft feparated by precipitating the whole and treating the pre- cipitate with diftilled vinegar. Laftly, Calcareous Earth and Earytes are feparated either by precipitating the barytes by the Pruffian alkali, or the calcareous by a cauftic fixed alkali, or by precipitating both with the vitriolic acid, and evaporating the folution to a frnall compafs, pouring off the liquor and treating the dried precipitate with 500 times its weight of boiling water ; what remains undiflblved is barofelenite. Table of the comparative hardnefs of different Species of Stones, extracted chiefly from the Memoirs of Stockholm^ for 1768. Mr. ^#/)?, the author of this Memoir de*- termined the hardnefs of moft of the follow*- ing ftones, by obferving the order in which they were able to cut and make an impreffion on each other. The firft are able to cut or /cratch the fucceeding, but not vice verfa. He added alfo the fpecific gravity of the fpe- cimens he ufed; the firft column fhews the hardnefs; the fecond, the fpecific gravity. The four laft fpecies I have added from my pwn pbfervation. Diamond 172 Elements, of Mineralogy. Diamond from Ormos> - 20 Pink Diamond, - - 19 - 3,4 Bluifh Diamond, - - 19 - 3,3 Yellowifh Diamond, - 19 - 3,3 Cubic Diamond, - - 18 - 3,2 Ruby, - - ~ 17 - 4,2 Pale Ruby from Brazil, - 16 - 3,5 Spinel, - - i3-3»4 Deep blue Sapphire, - - 16-3,8 Ditto palel, - - - 17 - 3,8 Topaz, - - - 15-4,2 Whitifh ditto, - - 14 - 3,5 Bohemian, - - - 11-2 ,8 Emerald, - - - 12-2,8 Garnet, - - - 12 - 4,4 Agate, - - - 12 - 2,6 Onyx, - - - 12-2,6 Sardonyx, - - - 12 - 2,6 Amethyft, - - -11-2, 7 Cryftal, - - - 11-2,6 Carnelian, - - - 11-2,7 Green Jafper, - - n 2,7 Redoifh yellow ditto, - 9 - 2,6 Shoerl, - - 10 - Tourmaline, - * 10 Quartz, - - - 10-2,7 Opal, - * - - jo - 2,6 Chryfolite, - - - 10 - 3,7 Zeolyte, - - 8-2,1 Fluor, - - - 7 - Calcareous Spar, - - 6 - Gypfum Table of Hardnefs: I 73 Gypfum, - - 5 - Chalk, - 3 - Remarks. if£* Artificial gems are eafily diftinguiflied from the natural, by their foftnefs, fufibility, folubility in acids, and in many cafes by their fpecific gravity. d 2dly* Stones whofe hardnefs does not exceed 1 1 may be fcratched by fteel. 3diy- It is remarkable that opal whofe hard- nefs is equal to that of quartz, does not ftrike fire with fteel, as Mr. Bergman attefts, is this owing to its brittlenefs ? but itfeems that opals are of different degrees of hardnefs, for Mr. Quift in a letter to Mr. Rinman, men- tions his having feen opals nearly as hard as- diamond. Mem. Stock. 1766. PART 1 74 Elements of Mineralogy, PART II, Saline Subftances. AL L thofe fubftances which are kriown only by this denomination, require leis than two hundred times their weight of boil- ing water to diflblve them. • They have moftly a peculiar tafte, and thofe of the mineral kind are uninflam- mable. CHAP. L Of Adds. The Acids to 'be met with in the mineral kingdom, are the aerial, the vitriolic^ the marine^ the fparry, the fuccinous, phofphoric^ nwlybdenous, arfenical, and tungflenic. The Aerial Acid is found either in an aerial ftate, as in mines, caverns, wells, or combined with water in mineral or common fprings, or combined with abforbent earths, or in ores, &c. it is eafily known by its pro- perty of extinguiihing lights, uniting to water, and then precipitating lime water, but not a folution of nitrous felenite. The Salts. 175 The Vitriolic when dephlogifticated, is always united to water, and as in the Earth, it muft meet with bodies with which it is capable of combining, I believe it has never been found free from all combination, though it may unite to fome bodies beyond the point of faturation. It is true Mr. Balta/ari fays, he found fome dry concentrated acid, adhe- ring to felenite in a grotto in Monte Zaccolino near Sienna. 7 Roz. but this has been fully difproved by the fubfequent obfervations of Mr. Murray, in the 37th vol. of the Me- moirs of Stockholm. In a combined ftate it is found in various neutral falts. , The phloglftigated or fulphurous vitriolic acid, frequently occurs in a free aerial ftate, burfting from volcanic mountains, and alfo in fome caverns and mineral waters. Of the other acids, none has hitherto been found in an uncombined ftate, except the JeadtitV€9 which has lately been found by Mr. H%ff'er> diffolved in the Laguni, or lakes of hot mineral water near Monte Rotundo^ Ber- chiaio, and Caftelnuovo in Tufcany, in the pro- portion of nearly 9 grains in 100 of water. Mr. Mafcagni has likewife found it adhering to fhiftus on the borders of the lakes, of a dirty white, yellow or greenifh colour, and cryftalized in the form of needles, i6Roz. 364. This j 76 Elements of Mineralogy. This Salt requires at leaft 20 times its own weight of boiling water to diffolve it, and 50 times its weight to keep it in fo- lution. It is alfo foluble in hot fpirit of wine, and this folution burns with a greenifli flame. Its folution in water, when heated, turns that of litmus red. It vitrifies in a moderate heat, but the glafs fo formed is again foluble in water. Its fpecific gravity is i ,479. The Nitrous Acid^ though generally ranked among the mineral acids, can fcarce be called fo, as it always requires for its for- mation, the putrefaction of animal or ve- getable fubftances. It is never found dif- engaged from all bafes (except perhaps in charnels and privys), but always united either to alkalis or Earths. The Marine Acid is found only in a ftate of combination with alkalis, earths and fome metals. The Sparry is found in fluor fpars, lapis lazuli, chryfoprafium, and phofphoric blende. The Succinousy found only in amber. The Salts. 177 The Phofphoric has as yet been difcovered only in foffile bones, and in one fpecies of lead ore. It probably owes its origin to the decornpofition of bones. The Molybdenous acid being very lately known, has been found only in molybdena. The Arfenical acid has been traced in the ores of other metallic fubftances, particularly of cobalt. The Tung ft en acid has hitherto been found only in the calcareous ftone, called Tungften. CHAP. II. Of Alkalis. Thefe are of two forts, fixed and volatile; the fixed are either of vegetable or mineral origin, which differ in a few properties, but it is to be obferved, that forae vegetables afford alfo an alkali intirely fimilar to that of mineral origin, particularly marine plants, or thofe that grow near the fea ; neither of them is ever found in a cauftic ftate, but all are com- bined at leaft with the aerial acid. They then effervefce with moft other acids, turn infufions of blue flowers of certain vegetables N green, Elements of Mineralogy. green, cryftalife with the three ancient mineral acids, &c. The Vegetable Alkali, is feldom found in the earth, except in wells in towns, as at Dow ay i &c. 4 Mem. Scat). Etr. alfo in the argillaceous allum ore of la Tolfa, and united to the nitrous acid near the furface of the earth in Spain and the Eqft Indies, probably from the putrefaction of vegetables. The Mineral Alkali is not only found in a ftate of combination with the vitriolic and marine acids, but alfo very commonly with the aerial, with which it retains, not only the name, but many of the properties of a free alkali, as the aerial' acid is eafily ex- pelled. In this mild ftate it is eafily known by its cryftalization, folubility in 2,5 times its weight of water, in the temperature of 60, efflorefcence by expofure to the air, ef- fervefcence with acids, and the properties of the different neutral Salts, refulting from its union with the different acids, decompofing /£VT£W0-neutral and ammoniacal Salts, &c. loo Parts of this alkali, when perfectly pure and recently cryftalized, contain ac^ jcording to Mr. Bergman^ 20 of mere alkali, 1 6 of aerial acid, and 64 pf water ; my de-» termination Salts. 1 79 termination was fomething different from this, but then the Salt had loft fome of its water by expofure to the air. This alkali is found in Hungary \n marfhy grounds of an argillaceous or rnarly nature, either mixed with earth, or cryftalized and efflorefcing. In Egypt it is found at the bottom of lakes, dried up by the fummer's heat. Alfo in the province of Stafis from that of Epfom.i but the precipi- tate retains nearly I the weight of the acid with which it was originally united, and is in reality Embryon Alum ; but by digefting it in volatile alkalis (for its bafis would unite to fixed alkalis) it may be perfectly purified. Its folution, like that of Epfom^ renders nitrous folutions of filver or chalk turbid, but mixes uniformly with thofe of nitrous or marine alum, or of the vitriols of any metal : thefe properties diftinguifh it fufEciently. 100 parts of it contain about 24 of acid, 1 8 of earth, and 58 of water. This fait is found native in a few mineral fprings*, though rarely, i Bcrgm. 280. and * Margr. 2 193. ia Salts. 185 in the mineral lakes of Tufcany, 16 Roz. 362. alfo germinating on the furface of free ftone or fhiftus in coal mines, or on lavas near volcanos, and on feveral rocks in the Arch'jpelago, and in feveral parts of Hungary, Bohemia, and Swifferland, though feldom pure ; but far the greater part of it is facti- tious, being extracted from various ores, the principal of which are the following : SPECIES VII. fo alfo from cala- mineand pyritaceous wood. Native alum, mixed with vitriolic ammo- niac, is found cryftalized on the borders of the mineral lakes of Tufcany. 16 Roz. 363. it is alfo found in a capillary form near the lake of St. Agnano, in the grotto of St. Germano. 37 Mem. Stock. SPECIES VIII. Salts. 189 SPECIES VIII. Vitriol of Iron. It is of a greenifh colour when perfectly and recently cryftalized, but efflorefces by expofure to the air, and becomes yellowifh : it requires 6 times its weight of water to dif- folve it in the temperature of 60 ; its acid is known by this, that the folution of this fait mixes without turbidity with the folutions of other ialts that contain the vitriolic acid, as Epforn, felenite, tartar vitriolate, &c. but renders the folutions of nitrous or marine felenite turbid ; and its bafis, by the black colour which the folution of galls or vegeta- ble aftringents immediately produce in its folution. 100 Parts of it recently cryftalized contain 20 of real acid, 25 of iron and 55 of water. It is frequently found native, either in coal mines, or in the cavities of pyritaceous mines, or adhering to the fcaffolds in a ftalac- titical form. Alfo in fmall round ftones called Ink ftones, of a white, red, grey, yellow or black colour, which are almoft intirely folu- ble in water, and contain a portion of copper and zinc. 2 Schlutter, 620. 2 Jars, 26$. Alfo fometimes in ihiftus. But the greatdl part jgo Elements of Mineralogy. part of that in ufe is prepared from the mar- tial pyrites or mundic. Martial Pyrites is an iron ore containing from -i to 1. of fulphur, from f to 4 of iron, the remainder argill and filex, the three firft intimately combined with each other, and the iron in a femiphlogifticated ftate. Monnet Eaux Miner. 281. 2 Gerh. Beytr. 57. It ftrikes fire with fteel, and thence derives its name; it is generally of a yellow or grey colour, of a globular or cubic fhape, inter- nally radiated and fometimes lamellar, com- monly in part foluble in nitrous acid with effervefcence, and flowly in the vitriolic, with which it forms alum ; it detonnates flightly with nitre and is very infufible : its fpecific gravity is from 3,7 to 4,912, - Some pyrites inftead of argillaceous contain calcareous Earth, thefe are common in France, and in them the iron is in a dephlogifticated ftate. Monnet Mineral. 339. Pyrites are frequently found in a ftatadtical fhape, and often form the matter of petrifactions : they are alfo found mixed and interfperfed through almoft every other fpecies of ftone except granite. Accord- ing to Mr. Monnet, thofe of a filamentous or ftriated texture contain leaft fulphur, thofe of a lamellar, moft ; the laft efflorefce diffi- cultly if at all, and are faid to contain from 25 to 35 per cent of fulphur, Vitriol Salts. igi Vitriol is formed in thefe ftones by expo- (ing them a long time to the action of the air and moifture, or by torrefadion in open air, and fubfequent expofition to its aftion, which operation in fome cafes muft be often repeated, according to the proportion of ful- phur, and the nature of the Earth ; the cal- careous pyrites are thofe in which it is moft eafily formed, and they effloreice the fooneft, good pyrites properly treated, yield about ^ of their weight of vitriol. Vitriol is alfo prepared from mineral waters that hold copper in folution, which is preci- pitated by iron ; this foUition of iron is after- wards cryftalizedand always retains forrtfj cop- per. In Hungary it is prepared from pyrita- ceous fhiftus, and in many places from a fpe- cies of calamine; the vitriol of goflaar com-, monly contains a portion of zinc, as that of Hungary and Saxony does of copper; the 'Englifh and French vitriols are purer, yet fometimes contain a fmall proportion of alum. Turf and peat are fometimes impregnated with vitriol; other earths alfo often contain vitriol and alum. Mon. Mineral. 460. This vitriol is fometimes found of a white colour on the borders of the mineral lakes of Tufcany. 1 6 Roz. 36 3 1 SPECIES IX. 1 92 Elements of Mineralogy, SPECIES IX. Vitriol of Copper. Its colour is blue, which degenerates into a mixture of blue and rufiy yellow after it has been long expofed to the air ; it requires about four times its weight of water to dif- folve it in the temperature of 60. Its fpecific gravity is about 2,23 ; if a piece of clean po- lifhed iron be dipped into the folution of this fait, it will almoft immediately be covered with a cupreous coat, this together with the deep blue colour ariiing from mixing it with a volatile alkali, diicovers its bafis, as its uniform mix- ture with other vitriolic falts does its acid, i oo Parts of vitriol of copper contain 30 of real acid, 27 of copper, and 43 of water. 80 Parts of good iron precipitate 100 of cop- per, from a folution, that does not contain a notable excefs of acid. This fait rarely occurs cryftalized, but is often found naturally diflblved in water, in Hungary, Sweden and Ireland: from this water blue vitriol is generally prepared. Mr. Cronjled fays it is feldom free from iron and zinc ; it is alfo occalionally extracted from fulphurated copper ores after torrefadion. Scblutt. Salts* 193 Schlutt. 638. According to Mr. Cronjlcd> the blue vitriol of Gojlaar contains a mixture of zinc. SPECIES X. Vitriol of Zinc. Its colour is white, it requires little more than twice its weight of water to diffolvc it in the temperature of 60; its fpecific gravity is about 2,000 ; it mixes uniformly with vitriolic neutral falts, but precipitates nitrous or marine felenites from their folutions, which afcertains its acid principle; it is itfelf precipitated whitifh by alkalis and earths, but not by iron, copper, or zinc, which fuffici- ently indicates its bafis ; if it contains any other metallic principle, this may be precipi- tated by adding more zinc, except iron, which will of itfelf precipitate by expofure to the air, or boiling in open air. 100 parts of vitriol of zinc, contain 22 acid, 20 of zinc, and 58 of water. This fait is fometimes found native, mixed with vitriol of iron, and in the form of white hairy cryftals, 2 Linne in the fame circumftances. 100 Parts of cubic nitre contain about 29 of real acid, 50 of mineral alkali, and 21 of water. According to Mr. Bowles, it is found native in Spain. O 3 SPECIES XVII. Elements of Mineralogy. SPECIES XVII. Nitrous Ammoniac. It generally deliquefces j when mixed with a fixed alkali, the volatile betrays itfelf by its fmell ; it deflagrates when the containing veflel is heated nearly red ; with fpirit of fait it makes aqua regia. 100 Parts of it contain 46 of nitrous acid, 40 of volatile alkali, and 14 of water, as I believe. It is frequently found in the mother liquor of nitre, Linne von Gmelin^ 332, Weber Abhand) von den Salpetre> 17. SPECIES XVIIL Nitrgus Selenite, This alfo deliquefces, its tafte is bitter, fixed alkalis decompofe it, and form cubic or prifmatic nitre, but cauftic volatile alkali cannot decompofe it, it does not deflagrate, yet paper moiftened with a faturate folution of it, crackles on burning, it lofes its acid in a ftrong red heat, its folution will not trouble that of filver in the nitrous acid ; vitriolic acid will precipitate its bafis, as will the acid of fugar, 100 Salts. 199 100 parts of it contain, when well dried, about 33 of acid, 32 of calcareous earth, and 35 of water. It exifts in old mortar, and the mother liquor of nitres alfo in chalk rocks near Rocheguyon. Macquers Di£l. Nitre. SPECIES XIX. Nitrous Epfom Deliquefces, does not deflagrate, does not render the nitrous folution of filver turbid, is precipitated by cauftic volatil alkali, and alib by the acid of fugar, but the precipita- tion is fcarce apparent, unlefs fpirit of wine or evaporation be applied. If nitrous fele- nite and nitrous Epfom be mixed, and both fo- lutions be faturated, a precipitate will alfo ap- pear ; neither vitriolic acid nor mild magnefia occafion any turbidity in its folution. 100 parts of it contain about 36 of real acid, 27 of magnefia, and 37 of water. It exifts in old mortar, and is found in the mother liquor of nitre. O 4 SPECIES XX. 20Q Elements of Mineralogy, SPECIES XX. Salt of Sylvius Requires about 3 times its weight of water to diflblve it; its fpecific gravity is 1,836; diffolved in nitrous acid it makes aqua regia ; it forms a cloud in the nitrous folution of filver ; fixed alkali precipitate nothing from its folution, nor does a mixture of marine felentine, but the acid of tartar caufes a pre- cipitate. loo parts of it contain about 30 of real acid, 63 of vegetable alkali, and y of water. It is found in fome boggs in Picardy, and fome mineral waters in Normandy* Monnet Hydrolog. 263* SPECIES XXI. Common Salt Requires about 2,5 its weight of water to diflblve it in the temperature of 60 ; its fpe- cific gravity is 2,12; the acid of tartar pre- cipitates nothing from it ; in other refpefts it agrees with the above. 100 parts of it contain 33 real acid, 50 of mineral alkali, and 1 7 of water. Salts. 201 It is not only found in the fea, fait lakes, and many fait fprings in the proportion of even 36 per cent, but alio in large mafTes under the earth in many countries, as Poland^ England, Tyrole, &c. alfo in coal and beds of gypfum. Born's Index. Its colour is either grey, red, blue, yellow or black. Cronjled §. 129. Born. SECTION XXII. Sal Ammoniac Requires about 3,5 times its weight of water to diflblve it in the temperature of 60 ; its fpecific gravity about 1,42 5 it makes aqua regia when mixed with nitrous acid » it diflblves copper * it wholly evaporates when laid on a hot iron. 100 parts of it contain 52 of real acid, 40 of volatil alkali, and 8 of water. It is found native and of different colours, grey, black, green, red, in the neighbour- hood of volcanos, and in the mineral lakes of Tufcany. 16 Roz. 362. Alfo in fome mountains of Tartary and Thibet. 2 Linne and infoluble in water and fpirit of wine, but foluble in fome fpecies of oil. Mr. Lergman fays he poflefTes a concrete rape-feed oil, which is hard and pellucid like copal, and infoluble in water and fpirit of wine. 2 Erde. Befchr. 267. SPECIES I. Inflammables. 209 SPECIES I. Inflammable Alr^ Fire Damp. This is eafily known by its property of inflaming, when mixed with twice or thrice its bulk of common atmofpheric air. When pure, it explodes all at once, but when mixed or combined with fixed air, it burns with a blue lambent flame. It frequently occurs in coal-pits and mines, and often on the fur- face of fprings in Perfia, Italy > and France* and feems to be nothing more than the ex- halation of petrol. SPECIES II. -" Hepatic Air. This air feems to confift of fulphur, held in folution in vitriolic or marine air ; it is in- flammable when mixed with -| of its bulk of common air. Water will take up about i its bulk of this air, and when faturated with it will turn filver black, but if ftrong dephlogifti- cated nitrous acid be dropped into this water, the fulphur will be precipitated. loo Cubic inches of this air, when united to water, may hold 8 grains of fulphur in P jfolution, 2 1 o r Elements of Mineralogy. folution, in the temperature of 60, and more if hotter. Pure air alfo decompofes hepa- tic air. It is (found in many mineral waters, and particularly in the hot baths of Aix la Chapelle. The caufe and manner of their containing fulphur, which was long a problem, has at laft been happily explained by Mr. Bergman. It plentifully occurs in the neighbourhood of volcanos, and in feveral mines. SPECIES HI. Naphtha. A fine thin fragrant colourlefs oil, which iflues out of white, yellow, or black clays in Perfia and Media^ is known by this name. It burns with a bluifli yellow flame, and is as inflammable as aether, and like it, extracts gold from Aqua Regia. It is not decompo- fed by diftillation, and yet if long expofed to the air, it changes colour, thickens, and de- generates into petrol. Its fmell is very dif- ferent from that of vegetable oils ; it diflblves refins and balfams, but not gum refins, nor claftic gum. It diflblves the eflential oils of thyme and lavender, but is infoluble in fpirit of wine andaether. Its fpecific gravity is 0,708. SPECIES Inflammables* 21 i SPECIES IV. Petrol^ Bergoel) Steinoel. Dodlor Pneftky has fhewn in the ^d vo- lume of his Observations and Experiments on Air, that eflential oils, l|ng expofed to the atmofphere, abforb not only the pure part, but alfo the phlogifticated part of it. An abforption, which muft, in time, produce confiderable changes in them ; by a procefs of this fort, naptha is converted into petrol, which is an oil of various degrees of denfity, according to the time during which it has been expofed to the atmofphere ; its colour is reddim, or yellow, brown, greenim, or blackilh, it is found trickling from rocks, or iffuing from the earth in the Dutchy of Mo- dena, and in various parts of France, Sivif- Jerland, Germany, and Scotland^ as well as in Afia. Alfo on the furface of the water of different fountains, or mixed with earth and fand, from which it is feparated by infufion in water ; the thinneft fort poflefles the pro- perties of naphtha, though in a lefler degree. It is rendered finer by diftillation with water, and leaves a refmous refiduum, and if dif- tilled with a volatil alkali, the alkali ac- quires the properties of fuccinated ammoniac, and hence contains the acid of amber. Some forts of it, according to Monet, are nearly P 2 of 2 1 2 Elements of Mineralogy. of the denfity of nut oil. It is infoluble in fpirit of wine. SPECIES V. Barladoes tar, Erdepech, Bergtheer, Kedria* terrejiris, Maltha. Petrol long expofed to the air, forms this fubftance. It is of a vifcid confiftence, of a brown, black, or reddifh black co- lour, fometimes inodorous, but generally of a more or lefs difagreeable fmell, par- ticularly when burned. It eafily melts, and burns with much fmoke and foot, and leaves either afhes or a flag, proceeding from heterogeneities contained in it. Spirit of wine cannot diflblve it. It contains a portion . of the fuccinous acid, for with mineral al- kali it gives a bitter fait, more difficultly fo- luble than common fait, and which treated with charcoal, will not afford fulphur. Mem. £erlin, 1758. It is found in Perfia, in the neighbourhood of Petrol^ in ftrata of gypfum and lime- ftone, or floating on water, alfo in Siberia, Germany, Switzerland, and in coal-pits, alfo in America* SPECIES Inflammables. SPECIES VI. Affhaltum, ludenpech, Berghartz, $tsinpech> Erhartete Bergtheer. This is a fmooth, hard, brittle, inodorous black or brown fubftance ; it breaks with a ftnooth fhining furface, melts eafily when heated, and when pure, burns without lea- ving aay afhes, but if impure, leaves allies or a flag. According to Mr. Monnet, it contains fulphur, or at leaft the vitriolic acid, which feems confirmed by the experiments of Meffrs. Gerhard* and Thory^ it is flightly and partially a£led on by Alcohol and aether. It is found on the fhores of the Red Sea, aUb in Sweden, Germany 9 and France. S?ECIES VII. Mineral tallowy Mumia, Beleffbon* This was found in the fea on the coafts of Finland, in the year 1736; it is perfe&ly white, and of the confidence of tallow, but more brittle, though as greafy. Its fpecific gravity is 0,770, whereas, that of tallow is 0,969 ; it burns with a blue flame, and a fmell of greafe, leaving a black vifcid matter, which is more difficultly confumed, it is foluble in fpirit of wine only when tartarifed, and evea * 2 Beytrage. f 6 CrellChemifche Journal, p. 67. P 3 then £14 Elements of Mineralogy. then leaves an infoluble refiduum, but ex- prefled oils diflblve it when boiling. It is alfo found in fome rocky parts of Perjia> but feems mixed with petrol, and is there called Schebennaad, Tfienpen, Kodreti.* Mr. Herman, a phyfician of Strqfburgh, mentions a fpring in the neighbourhood of that city, which contains a fubftance of this fort diffufed through it, which feparates on ebullition, and may then be collected, 3 Roz. 346. SPECIES VIII. Jet, Gagates, Lapis Obftdianus. Jet is much harder than afphaltum, always black, fufceptible of a good polifh and glaffy in its fradure, which is conchoidal ; it is highly eledrical; its fpecific gravity is 1,744; it melts in a moderately ftrong heat with a difagreable fmell, when burnt it leaves a grey earthy ochrous refiduum ; it is infoluble in fpirit of wine. It is found in England, Scotland, France, Italy, Germany, &c. SPECIES IX. Pitt or Stone Coal. Lithanthrax. Coal is a black, folid, compacl, brittle, in- flammable fubftance, of a moderate hardnefs, * J^fem. Su(d. 87. 2 Lin. von Gmel. 389. 2 Gcrb. Beytr. 211. laminated Inflammables 215 laminated texture, more or lefs fhining, but rarely fufceptible of a good polifh, does not melt when heated, and always leaves fome afhes ; it feems to confift of petrol or afphal- tum intimately mixed with a fmall proportion, of Earth, moftly argillaceous, feldom calca- reous, and often with pyrites ; according to Mr. Gerhard, fpirit of wine extracts a red colour from it, cauftic fixed alkali attacks the bituminous part, and fat oils aft on and form a varnifh, at leaft with fome forts of it : a fixed alkali has never been found in it, nor any fulphur, except it contained pyrites. Four varieties of it deferve to be diftin&ly confidered : none of them are eledrics ferje* I. and II. VARIETY. Cannel Coal, and Klllkenny Coal. Cannel coal is of a dull black colour, breaks ealily in any direction, and in its fra&ure prefents a fmooth conchoidal furface, if broken tranfverfly : this fort contains moft petrol and in a lefs denfe ftate; hence it burns with a bright lively flame : its fpecific gravity is about 1,27; Klllkenny coal con- tains the largeft proportion of denfe petrol or afphaltum : and hence burns with lefs flame and fmoke, and more (lowly though intenfely, the quantity of Earth in this coal iloes not exceed T~ of its weight : its. fpecific P 4 gravity 2 1 6 Elements of Mineralogy. gravity is about 1,4, it is frequently mixed with pyrites. III. VARIETY. Coal containing a moderate proportion of Petrol and Bitumen. This burns with more or lefs flame accord- ing to the proportion of petrol; in its fracture, it prefents a rougher furface than Canne/coal: its fpecific gravity is from 1,3 to 1,37; the beft coal is of this fort, by diflillation it affords firft fixed air, then an acid liquor, afterwards inflammable air, and a light oil of the nature of petrol, then a volatil alkali, and laftly a denfe pitchy oil ; the refiduum is nearly I of the whole, and being flowly burnt, affords 13 percent, of aihes, which is moftly argillaceous Earth, of which T^- or thereabouts is magnetic. Mem. Stock. 1781. j oo Parts of this coal contain about 1 7 of Earth, of which 4 are martial; hence we fee that coal does not confift of a fhiftus pene- trated with petrol, as many have thought, for then a large proportion of filex, mag- nefia, ari4 calcareous earth fhould be founci JV. VARIETY, Inflammables. £17 IV. VARIETY. Sulphureous Coal. This confifls of the former mixed with a notable proportion of pyrites : hence it is apt to moulder and break when expofed to the air, and contains yellow fpots that look like metal ; it burns with a fulphureous fmell, and leaves red afhes, or a flag ; water a£ts upon it after it has mouldered : its fpecific gravity is 1,5, or more. Befides thefe varieties, fhiftus, micaceous fhiftus, and gneifs are frequently found in the neighbourhood of coal-mines fo penetrated with petrol or bitumen as to conftitute an inferior fpecies of coal, but the bitumen being burnt, they preferve their form, and in fome meafure their hardnefs ; I have alfo feen grey flates fo foft as to be fcraped with the nail, and which were greafy to the touch, that burned like coal. All the different fpecies of coal arife from a mixture of the varieties here enumerated. Note. That wherever coals exift, flates are found near them, and fait or mineral fprings pften in their neighbourhood. SPECIES X 2i 8 Elements of Mineralogy. SPECIES X. Bovey Coal, Taub Kohle. Xylanthrax. This is of a brown, or brownifh black co-» lour, and lamellar texture, the laminse are fre- quently flexible when firfl dug, though gene- rally they harden when expofed to the air ; it confifts of wood pen-etrated with petrol or bitumen, and frequently contains pyrites, alum, and vitriol j its afhes afford a fmall quantity of fixed alkali, according to the German chymifts ; * but according to Mr. Mills they contain none ; '\ by diftillation it yields an ill fmelling liquor, mixed with volatil alkali and oil, part of which is foluble in fpirit of wine, and part infoluble being of a mineral nature. It is found in England^ France^ Italy ^ ferland) Germany ', Iceland* SPECIES XL Peat Geanthrqx. There are two forts of inflammable fub- flances known by this name; the firft and principal is of a brown, yellowifh brown, or black colour, found in moory grounds, iGerb. Beytr. 271. f Pbil. Tratts. 1760* Inflammables. 219 and when frefli of a vifcid confidence, but hardens by expofure to the air ; it confifts of clay, mixed with calcareous earth and py- rites, and fometimes contains common fait; while foft it is formed into oblong pieces, and the pyritaceous and ftony matters are fepa- rated ; when diftilled it affords water, acid, oil and volatil alkali, and its afhes contain a fmall proportion of fixed alkali ; they are either white or red according as it contains more or lefs ochre or pyrites. 2 Ed. EJfays, 244. 2 Gerh. Beytr. 265. It is found in Scotland, Holland, and Germany. Another fort is found near Nerwbury in Berk/hire ; it contains but little earth, but confifts chiefly of wood branches, twiggs, roots of trees* with leaves, grafs, ftraw and weeds. Phi!. Tranf. 1757. p. no. SPECIES XII, Turf. This confiPts of mould interwoven with the roots of vegetables ; when thefe roots are of the bulbous kind, or in large proportion, they form the loofer and worft kind of turf; but when mixed with a confiderable propor- tion of peat, they form what is called jfcwkf turf", it at firft hardens, but at laft crumbles by long expofure to the air. SPECIES XII& 220 Elements of Mineralogy. SPECIES XIII. Amber^ Bernftelny Agtftem, Succinum^ Elec~ trum, Carabe. Amber is a hard, brittle, taftelefs fub- fiance, fometimes perfectly tranfparent, but moftly femi-tranfparent or opake, and of a glofly furface ; it is found of all colours, but chiefly yellow or orange, and often con- tains leaves or infefts ; its fpecific gravity is from 1,065 to i>IO°> its frafture is even, fmooth and glofly; it is capable of a fine polifh, and becomes eleftric by fri&ion; when rubbed or heated, it gives a peculiar agreeable fmell, particularly when it melts, that is, at 550 of Fahrenheit, but it then lofes its transparency ; projected on burning coals, it burns with a whitifh flame, and a whitifh yellow fmoke, but gives very little foot, and leaves brownifh afhes ; it is in- foluble in water and fpirit of wine, though this latter when highly rectified extracts a reddifh colour from it, but it is foluble ia the vitriolic acid, which then acquires a red- difh purple colour, and is precipitable from it by water ; no other acid diflblves it ; nor is it foluble in fixed alkalis, nor in eflential oils, nor in expreiied, without fome decompo- fition, and long digeftion ; but balfams dif- folve it readily 5 75 gr, of it alkalife 100 of nitre, Inflammables. 221 nitre, and therefore too gr. of it contain nearly 90 of phlogifton ; by diftillation it affords a fmall quantity of water, an oil of the nature of petrol, and a peculiar acid called the fuc- cinous acid, btockar, p. i , n, 17, &c. Ac- cording to Baumer Reg. Men. 22. loo gr. of amber afford about 72 of petrol, and 4,5 of fait, that is, fuccinous acid; the remainder was fixed, or water. It is found in mafles of different fizes in feveral pits in Germany, particularly in PruJJia, but the beft fort is that which is taken out of, or caft on fhore by the fea. Ac- cording to Mr. Scheele amber yields by diflil- .lation an aqueous acid, which poffefles all the properties of vinegar ; if fo, it is probably of vegetable origin. Scheff. Forlef. §. 68. i Anmerk. Ambergris, Ambra. This is a grey, brown, yellowifh, black or brown fubftance, of the confiftence of wax, and an agreeable fmell, lighter than water, and eafily inflammable, caft up by the fea on the coafts of Madagafcar^ Coromandel^ &c. but as Dr. Sivediar has lately proved it to be of animal origin, I fhall take no further notice of it. 222 Elements of Mineralogy. Copal. Mr. Lehman and many others rank this alfo among minerals; but Mr. Bloch, in a ftill later diflertation, has fatisfadorily proved that it belongs to the vegetable kingdom. 2 Befchaft. BerL Gejellfch. p. 91. SPECIES XIV. Sulphur, Brlmftone. Sulphur is a taftelefs, hard, brittle, idio- eleftric fubftance, of a yellow or greenifh yellow colour, whofe fpeciiic gravity is from 1,9 to 2,35. According to Mr. Bergman it gently evaporates at 170, melts at 185, and flames at 302 of Fahrenheit. 3 Bergm. 242. It burns with a blue flame, and a difagreeable fuffocating fmell ; in clofe veflels it fublimes without decompofition, or only a decompofi- tion proportionable to the quantity of air they contain ; when melted it becomes red, but recovers its colour on cooling. It is infoluble in water, though by long trituration it is faid water will take up fome of it, but I believe it is rather diffufed thro* than diflblved in it ; neither can fpirit of wine unite to it, except when both are in a vaporous ftate, and then 72 parts of fpirit of wine InjlammMes. 223 wine take up i of fulphur ; it is foluble in hot oils, and alfo in fixed alkalis both in the dry and liquid way ; it is decompofed by boiling in concentrated nitrous acid, partly decompofed and partly diflblved by the vitrio- lic, and dephlogifticated marine acid ; it con- fifts of vitriolic acid and phlogifton united nearly in the proportion of 3 to 2 5 for 100 gr. of fulphur contain about 60 of acid, and 40 of phlogifton. It is found native either in folid pieces of indeterminate fhape, running in veins thro* rocks, or in fmall lumps in gypfums and lime-ftones, and in confiderable quantity in folfatera and the neighbourhood of volcanosf or cryftalized in pale, tranfparent or femi- tranfparent, ocltagonal or rhomboidal cryf- tals, in the cavities of quartz, and particu- larly in the matrixes of ores, or in the form of fmall needles over hot fprings, or near volcanos, and fometimes in old privies. 2dly* United ivttb clay^ as in the alumi* nous ore of la Tolfa, and alfo at Tarnoivitz in Silefta. The former has been already de- fcribed, the latter is a light grey earth, which when dry burfts in water like marl, poflefles a ftrong peculiar fmell like camphor. If it be diftilled, fome fulphur fublimes. JOO 224 Elements of Mineralogy. 100 gr. of this earth afford 8 of fulphtif* befides gypfum, and a fmall quantity of iron* Mem. Berl. 1 75 7. 3dly. Mixed with clay, iron and fetenite* This compound is of a grey, brown or black colour, found near Rome, in Auvergne, Spain and Iceland. 2 Lin. *uon. Gmelin. 447. 0 Ume-ftone^ in the form of a calcareous hepar. This is found at Tivoli near Rome, and elfewhere in Italy. Mem. Par. 1770, p. 6. or diflblved in mineral wa- ters ; 3 pounds of which fometimes contain 25 gr. of fulphur. 2 Gerh* Beytr. 17. It often forms incruftations on the brinks of thefe fprings. 5thly' In the form of an alkalitie hepar* This is laid to be found in fome waters in RuJJia* Schab. Samm. 4 TheiL p. 544. alfo at Tivo/i. gthiy. unlted to iron and clay in pyrites* Laftly, United to various metallic fub- ftances, as fliall be feen in the next part. At Ramelfberg and the Hartz they extract fulphur from the fulphureous ores of filver, and lead mixed with pyrites, by fublimation during the torrefaction of thofe ores : this forms Inflammables, 225 forms Crude fulphur^ which is purified by a 2d fublimation ; but in Bohemia and Saxony they obtain it by immediate diftillation from the pyrites, and this is again purified by fublimation in clofe veflels. 2 Schlut. 222. Moft of that ufed here comes from Italy* Sulphur is difcovered in earths of ftones either by its inflammation, or by diftillation, with or without white arfenic or mercury, or by folution of the matrix in marine, or dilute nitrous acid, or by digeftion in, or fufion with fixed alkalis. PART 226 Elements of Mineralogy. PART IV. Metallic SubJIances. I. |V/f ETALLIC fubftances are opake *•**' bodies, whofe fpecific gravity ex- ceeds 5,000, confirming of a heavy, dull, brittle earth combinable with phlogiilon, and during that union pofifeffing a peculiar fhining appearance. They are all conductors of electricity, and more perfectly fo than any other bodies during their union with phlo- gifton. They are all foluble either in the nitrous acid, or in aqua regia, and all preci- pitable in fome degree by cauftic alkalis, and (except platina) by the P ruffian alkali ; all when dephlogifticated communicate a tinge to borax or microcofmic fait when melted 1 with thefe fluxes, or render them opake ; all melt in fome degree of heat, and moft com- monly affume a convex furface, or if in fmall quantity a globular form when in fufion, and in that ftate are mifcible with each other for the moft part, but refufe to unite with any other unmetallic fubflance, even their own calces * ; but when calcined they are * Iron is an exception to this rule, for even in its re- guline ftate it is capable of uniting to its own calces flightly dephlogifticated, and to plumbago : fome of them alfo may contain fulphur even in their regulme flate as nickel, &c. ' capable Metallic Snbflancesi 227 capable of union with other earths and falts, The phlogifton in all of them is in a pure ftate, that is, free from water and aerial acid, fubftances that invariably accompany it in all other compounds, except acid airs and fulphur. The more earthy part or calx of fome metallic fubftances has been found to be of an acid nature. 2. There are 17 metallic fubftances now known 5 namely, gold* platina, filver, cop- per, iron, lead, tin, mercury, zinc, regulus of antimony, regulus of affenic. bifmuth$ cobalt, nickel, regulus of manganefe, fyde- rites, and regulus of molybdena. Of thefe gold, filver, platina and mercury are reckoned perfect or noble metals, becaufe when calcined they recover their phlogifton without the addition of any phlogiftic fub- ftance : whereas copper, iron, lead and tin cannot be entirely reduced without fuch addi- tion, and hence are called ignoble or imper- fect : however, all thefe (even mercury wrhen folid) are malleable to a great degree, and hence called intire metals * whereas zinc, regulus of antimony, regulus of arfenic, &c. are fcarce at all malleable, and hence are called femi+metals : however zinc and purified nickel are more malleable than any of the reft. 228 Elements of Mineralogy. reft. Hence there are 4 perfect metals, 4 imperfect, 8 intire, and 9 femi-metals. 3. Metallic fubftances in their natural ftate are found either united to their full comple- ment of phlogifton, and confequently pof- fefling their refpeclive and peculiar proper- ties, and thence called native) or more or lefs deprived of their phlogifton, and the pro- perties refulting from their union with it, moft commonly, if not always, by combi- nation with fome other fubftance, and then they are faid to be mineralized, becaufe this is their moft ufual ftate in the mineral king- dom, and the fubftance fo combined with them is called a miner alizer ; the whole is called an ore ; fo alfo are earths and ftones, in which metallic fubftances are contained in a notable proportion. 4. When the mineralizer is of a faline nature, and renders 'the metallic fubftance with which it is combined foluble in lefs than 20 times its weight of water, the compound is generally ranged among filts : thus the vitriols of iron, copper and zinc are rather clafled with falts than with ores, 5. The commoneft mineralizers are ful- phur, arfenic, and fixed air : the leaft com- mon are the vitriolic and marine acids ; the phofphoric Metallic Sulftances. 219 phofphoric has been found only in one in- ftance ; metallic fubftances mineralized by fixed air are called calciform ores, from their refemblance to the calces formed by art. 6. It is true that fome mineralogifts of the firft rank exclude arfenic from the number of mineral izers, as it is itfelf a metallic fub- ftance, faying, that with equal propriety other metallic fubftances that render metals brittle might be called mineralizers ; they alfo add, that arfenic is never united to metals but in its reguline ftate, and therefore that the compound it forms mould rather be called an alloy than an ore .; and, indeed, if this laft circumftance always took place, I mould not hefitate to agree with them ; but it feems clear to me that the calx of arfenic, and even its acid being capable of uniting with metals, (an union which the calx of no other me- tallic fubftance is capable of contracting) thefe metals cannot unite to that calx or acid with- out lofing fome part of their phlogifton, and confequently without being mineralized in the ufual fenfe of that word ; yet if regulus of arfenic be combined with metals without any lofs of phlogifton (an union which art may produce by means of the black flux) I will allow the compound fhould rather be called an alloy ; but fuch an union I believe feldom or ever takes place in the mineral kingdom. Hence 230 Elements of Mineralogy, Hence I chufe to follow the common guage, which, without very cogent reafons, fhould never be departed from. 7. All metallic fubftances are therefore of neceflity {lightly dephlogifticated when united to fulphur ; but as metallic calces, in their moft dephlogifticated ftate, are allb capable of uniting with fulphur, hence it happens that they are fometimes more and fom^times lefs dephlogifticated in various fulphurated ores, particularly the pyritous. 8. Metallic fubftances mineralized by fixed air are alfo fometimes more and fometimes lefs dephlogifticated. 9. Metallic calces always containing fome foreign ingredient afford a fmaller weight when reduced ; and it is this laft that is moftly denoted, and when the proportion of pietal in any ore is affigned. CHAP. L Gold. i. The diftin&ive characters of gold arc the following : i°- A fpecific1 gravity reach- ing to 19,64. 2dly* Infolubility in all acids, except aqua regia, and the dephlogifticated marine Gold. ^ 23 1 marine acid, and precipitability from thefe acids in the form of a purple powder by fo- lution of tin, or in a metallic form by the folution of vitriol of iron.- 3dly' A yellow, or reddifh yellow colour when in its metallic ftate. Gold expofed to the utmoft heat of Mr. Parker's lens for fome hours loft no fenfible part of its weight, yet when in contact with earthy matters, it communicated a blue or purplifh tinge to them, fo that I believe an exceeding minute portion of it was dephlogifticated. Gold Ores. 2. Gold being incapable of uniting with ful- phur, or even with arfenic, but very diffi- cultly and while in fufion, or with fixed air, is for that reafon never found minera- lized, but either native or invifibly mixed with other fubftances. SPECIES I. Native. 3. Native gold is found either feparate from any matrix in lumps, or vifible grains mixed with fand, and in this ftate it is found in many rivers in France, Africa^ and elfe- where, or iavifibly difperfed through large mafles £3- Elements of Mineralogy. mafles pf fand, particularly the yellowiftt red, or violet, and in this ftate it is fo gene- rally diffufed through all fpecies of Earths, though in exceeding fmall quantity, that Mr. Bergman thinks it is more univerfally found than any other metal, except iron. 2 Erde. Befchr. 313. If ico pounds of fand con- tain 24 grains of gold, it is faid the feparatioa is worth attending to, hut in Africa^ 5 pounds of fand often contain 63 grains of gold, or even more ; the heavieft fand, which is often black or red, yields morT. In Hungary , 10,000 pounds of fand yield but 10 or 12 grains of gold -, it was extracted, but withlofs. Born, letters from Hungary. Or vjfitfy 'unbodied in fome matrix, and in this ftate it is found, either in a granular, foliated, or ramified form, in ftones of the calcareous, but chiefly of the filiceous genus, as fpar, gypfum, felt- fpar, hornblend, jafpar, and moft frequently quartz, in Hungary ^ Tyrole, Siberia^ &c. 4. Gold interfperfed through fand, is fepa- rated by mere mechanical means, as is amply defcribed in the Paris Memoirs 1718* and 1736, and Borns's Letters from Hungary. $. But when it is imbodied in Earths and ftones, thefe may be eflayed in the moift way b'y pounding them very fine, weighing a de-^ terminate portion, and attempting their fo- lutio n, Gold. 233 lution, if calcareous, in nitrous acid, which will diflblve the matrix, and leave the gold at bottom untouched, or if gypfeous or fili- ceous by digefting them in aqua regia, as long as any metallic fubftance is taken up, which the folution of tin, or phlogifticated alkali will indicate, and then precipitating the gold by a folution of vitriol of iron. 6. Or by Amalgamation, with -,'- of their wreight of mercury, in a copper or iron veflel, in which the mercury and pulverifed fand are put together with water, which is kept con- ftantly boiling, and the mercury after fome time, abforbes the gold, from which it is fe- perated by diftillation, Leew. Com. 194. — or by heating the fand red hot, and quench- ing it in water 3 or 4 times, then melting it with twice its weight of litharge, then reviving the litharge by charcoal, into lead, which then feparates from the fand, and laftly, freeing the gold from the lead by cup- pellation. Lewisy Ibid. 7. Native gold is feldom found perfectly pure, being generaly alloyed with filver, or copper, or iron, or all three. If fuch alloy be diffolved in aqua regia, the filver will re- main at the bottom in the form of horn filver, If then a iblutk)n of vitriol of iron be drop- ped into the folution of gold, this latter will be 234 Elements of Mineralogy. be precipitated, and the copper and iron may be precipitated by the phlogifticated alkali, and feparated as hereafter will be feen. SPECIES II. Mixed twith yellow or Martial Pyrites. 8. It is found thus mixed in the mine of Adelfors in Sweden. According to Cronjled^ § 166, ico pounds of this ore contains but one ounce of Gold, and it is faid to be hardly worth extracting. The pyrites is of a bright yellow colour, clofe and com pad:. The gold in this ore is faid to be mineralized by ful- phur, by the medium of iron, becaufe it can- not immediately be extracted by aqua regia or amalgamation, but Mr. Bergman^ though he inclines to the opinion of the mineraliza- tion of gold, yet is candid enough to own, that the gold, when extracted from this ore, being of a granular or angular form, it is very doubtful whether it was not rather mixed than truly combined with the ful- phur and iron, and its proportion being ex- ceeding fmall, it is not wonderful that it fliould efcape aqua regia, more efpecially as the nitrous acid becomes fo phlogifticated by a&ing on the pyrites, as not to be able to dephlogifticate the marine, and mercury, from the nature of things, can have no ac- cefs to it. 9. This Gold. 235 g. This and fueh like ores, may be eflfayed by diflblving them in about 12 times their weight of dilute nitrous acid, gradually added, and a heat of about 1 20 degrees ; this takes up the foluble part, and leaves the gold un- touched with the infoluble matrix, from which it may be feparated either by lotion, or by aqua regia,* from which it is precipitable as above. The fulphur floats for the moft part on the folution from which it mould be fe- parated by filtration. The folution may con- tain iron, copper, manganefe, calcareous Earth,, or argill j if it be evaporated to drynefs, and the refiduum heated to rednefs for half an hour, volatil alkali will extract the copper ; the dephlogifticated nitrous acid, the Earths ; the acetous, the manga- aefe ; and the marine, the calx of iron. i o Gold may alfo be feparated from py- jites after torrefadion, by aqua regia, Mon. Mineral. 277. 1 1 . Pyrites containing gold, is alfo found in Siwijjerland and Hungary, that found in Hun- gary, contains 5 ounces of gold per quintal, Mon. Expo/itions des Mhies^ p. 47, the gold mines of Norway, are of the fame nature as thofe of Addfors, 2 Jars. 12. la 236 Elements of Mineralogy. 12. In the dry way, Mr. Bergman eflfays thefe ores, by mixing 2 parts of the ore, well pounded and wafhed, with one and a half of litharge, and 3 of glafs, covering the whole with common fait, and melting it in a fmith's forge, in a covered crucible ;~ he then opens the crucible, puts a nail into it, covers it, and heats it again, and continues to do fo until the iron is no longer attacked. The lead is thus precipitated, and contains the gold which is feperated by cuppellation, Scheff. 239. i An- merk. SPECIES HI. Mixed 'with Arfenical Pyrites'. 1 3. Found at Salzbergh in Tyrole, in moun- tains of quartz and fhiftus; the quintal affords only about 25 grains. It is feparated by lotion, and affords a profit of between 4 and foe/, per an. 2 Jars. 78. SPECIES IV. Mixed 'with a white, red, or Vitreous Silver Ore. 1 4. Near Cremnitz and Scb&ttnifz in Hun- gary, 2 Jars. 165, 195. SPECIES Gold. 237 SPECIES V. Mixed 'With afulphurated Ore of Siher, frony Lead, and Manganefe. 15. Lately found at Nagaya in Tranfyl- vania. This ore confifts of fmall dark co- loured plates of more or lefs brightness, in- hering in quartz, and a foft whitifh fubftance, which Mr. Bergman found to be manganefe. Part of the gold may be extracted from it by eliquation in a cuppelling heat, its fufi- bility being promoted by the lead. 1 6. If the dark coloured plates be feparated from the remaining mafs, and treated with aqua regia, the gold and iron will be ex- tra6led, and may be feparated as above menti- oned, N? 7. but none can be extracted by amalgamation, ScopoL An. 3. p. 90. 17. This ore is faid to afford 10 ounces of gold per quintal, befides filver, its fpecific gravity according to Gdlert^ is 4,043. SPECIES VI. Mixed *with fulphur ated Iron and Copper ', with Manganefe. 18. This is a yellow pyrites, found alfo at in which gold is contained ; Mr. Bindhiini 238 Elements of Mineralogy. Bindhelm lately effayed this ore in a particu- lar manner. The pyrites being well pulve- rifed, were heated in an open crucible, until the fulphur was burnt off. The refiduum while hot, was thrown into water, a reddifh brown matter remained undiffolved. This, when dried, was diverted in 3 times its weight of aqua regia, then diluted and filtered, and aether poured on it and fhaken. The aether took up the gold, and being burnt off, left it in its metallic form, 4 Berl. Scbrijf. 393. 19. In Peru gold is found mixed with a ftony matter, not well known, and alfo with a red Earth, from both which it is there ex- traded by amalgamation, 2 Jars. ^ CHAP. II. Platina. 1. Platina has as yet been found only among the gold mines of Peru. It comes to us in the form of large fmooth grains, of an irregular figure, iome of them hollow, whiter than iron, intermixed with quartz, and a fer- ruginous fand, and in the cavities, fometimes particles of gold, but more frequently quick- lilver is found, which may be feparated by diftillation ; whence it is conjectured, that it is not brought to us in its natural ftate, but that it has been feparated from gold with other matters, Platina. 239 matters, by amalgamation. Moft of its par- ticles are friable and magnetic, but fome few are malleable to a confiderable degree, and may be feparated by a magnet, but according to the accurate experiments of Count Sickin- gen, even thefe contain about 1- of their weight of iron. Before it is feparated from quartz, its fpecific gravity is from 6,000 to i i,ooof and after that feparation from 1 6 to 1 8. It is ibluble only in aqua regia, or dephlogifticated marine acid, and is nearly infufible in terref- trial fires, the great burning lens of Paris only agglutinated its particles in 20 minutes, Mr* Parkers perfectly melted them in lefs than two. It is precipitable from its folution by falammoniac, as our late excellent chymift Dr. Lewis has difcovered, a property by which it is eafily diftinguiihed, and feparated from all other metals. It is not precipitable by the Pruffian alkali, as ail other metals are. 2. Its ores, if it has any, are not yet known* 3. Platina is purified from iron by reite- rated coclion in fpirit of fait, folution in aqua /egia, and precipitation of the iron, by the Pruffian alkali. When pure, its colour ap- proaches to that of filver, its fpecific gravity is nearly 23,000, it is not in the leaft mag- netic. CHAR 240 Elements of Mineralogy, CHAR III. Silver. 1. Silver is the whiteft of all metals ; its fpe- cific gravity when pure is 1 1*095 ; it is foluble in the concentrated vitriolic acid with the af- fiftance of heat, and in the moderately dilute nitrous acid without that affiftance ; it is pre- cipitable from both by the marine, and from the nitrous in great meafure by the vitriolic ; its calces are reducible without the addition of any phlogiftic matter, and it is incapable of calcination by mere heat. SPECIES I. / Native. 2. Native filver is found in a granular, lamellar, filamentous, capillary, arborefcent, or cryftalized form, inhering either in baro- felenite, lime-ftone, felenite, quartz, chert, flint, ferpentine, gneifs, agate, mica, calca- reous fpar, pyrites, ihiftus, clay, &c. alfo in feparate mafles of various fizes, fome of the weight of 60 pounds, in or near the veins of moft metallic fubftances, particularly in Peru* and frequently in various parts of Europe, either of a white, brown, or yellowifh colour. 241 3. It Is often diffufed through fandr £hd ochre, alfo in grey lime-ftone in Lower Aujtria^ and in a greenifh clay near Schem-* nitz, or miked with ochre, clay and cakiforra. faickel. 4. It is feldom found pure* being gene- tally alloyed with copper, and fometimes with a fmall proportion of gold, iron, or re- gulus of antimony *, and fometimes about 5 percent, of arfenicf ; it is f-parable from gold and regulus of antimony by folution in nitrous acid, and from copper and iron by precipitating it by the marine acid £, an4 from arfenic by torrefaftion. 100 gr. of the horn filver contain 75 of real filver ; it is reducible by triturating it with about its own weight of fixed alkali with a little watery then melting the whole in a crucible, whofe bottom is covered with mi- neral alkali well prefled, and covering the mafs of horn filver alfo with the mineral alkali. 5. The native filver found near Konigfoerg contains fo much gold as to acquire a yellow colour from it, . i * Bergm. Sciag. §,154. •[• 13 Roz, Supplem.ip. 56. t A more perfect manner of feparating it from copper toill befeen N°- 21* R SPECIES II. 242 Elements of Mineralogy* SPECIES II. Mineralized By 'Sulphur. Vitreous Silver Ore, Glafzertz. 6. It is found either in folid large lumps* or inhering in quartz, fpar, gypfum, gneifs> pyrites, &c. of a lamellar, granular or capil- lary form, or cryftalized ; it is generally of a lead colour firft, but grows black by expo- fure to the air, but fornetimes grey or black, even when firft broken; its laminae are flexible and du&il, and even malleable in fome degree, and fo foft, that they may be cut with a knife; its fpecific gravity is 7,200 * ; it is one of the richeft of the filver ores. 100 parts of it contain from 72 to 77 of filver ; it is rarely contaminated with any other metal befides a fmall proportion of iron. 7. It is found in Hungary near Sbemnitz, and in Saxony near Freyburgh> particularly in the fampus mine of Himmelsfurjt. 8. It is analyfed by boiling it in moderately dilute nitrous acid, ufing abou* 25 times its weight, until the fulphur is quite exhaufted. * GeJlert Anfangs. 234. Silver*. 243 The fiivef is precipitated by marine acid, or common fait, and eftimated as in N°- 4. The PruJJian alkali will fhew if any other metal is contained in the folution ; the gold, if any, will remain undiflblved ; fixed alkalis will precipitate any other earthy matters coia- tained in the folution, 9. In the dry way it may be reduced by inciting it with the blow-pipe on charcoal ; for the fulphur is diffipated^ and the filver re- mains ; or by melting it with \ of its weight of filings of iron, as the iron will take up the fulphur and be fcorified. SPECIES III. Mineralized by a fmall proportion of Arfenic. 10. This ore is of a yellowifh white co- lour, and of a ftriated texture, refembling bifmuth, bat much harder; it melts very eafily^ and if kept in fufion, it lofes its arfenic, and the filver remains almoft intirely pure, as it contains but very little iron ; it contains about 90 per cent, of filver, and is found near §>uadanal~Canal in Spain. Mon. Mineral. 281. SPECIES IV. Mineralized by a large proportion of Arfenic. 1 1 . The proportion of arfenic in this ore is fo great, that it would fcarce deferve to be R 2 called 244 Elements of Mineralogy. called a filver ore, if the arfenic were not eafily diffipated : the quintal contains but from 4 to 6 ounces of filver ; it is very foft, and eafily cut, and when cut has a brilliant metallic appearance ; it confifts of conchoidal laminae ; it is found alfo at t^uadanal- Canal. Mon. Ibid. 12. It is reduced by evaporating the arfenic, which then leaves the filver flightly contaminated with iron. SPECIES V. Mineralized by Sulphur and Arfenic. Red Silver Ore, Rothgulden ertz. 13. This is a heavy, fhining fubftance, either tranfparent or opake, moftly of a crimfon or reddifh colour, though fometimes grey or blackifh, but when fcraped or pow- dered always reddifh ; found either in fhape- lefs mafles, or cryftalized in pyramids or po- lygons, or dendritritical, or plated or radiated incruftations, on or in matrixes of quartz, flint, fpar, pyrites, fparry iron ore, lead ore, pyrites, cobalt ore, jafper, barofelenite, gneifs, &c. when radiated or ftriated, it is called rothgulden blutb. In fire it crackles and melts after it has acquired a red heat, with an arfe- nical fmell ; it detonnates with nitre ; its fpe- cific Silver. 245 cific gravity is from 5,4 to 5,684. Mr. Bergman found 100 gr. of it to contain 60 of filver, 27 of arfenic, and 13 of fulphur. 2 Bergm. 303. but fometimes it contains even 70 per cent, of filver. The darkeft ores are the richeft, and thefe often contain a little iron ; the yelloweft are the pooreft > the moft yellow does not belong to this fpecies, being in fa£t orpimeat, containing 6 or 7 per cent* of filver. 14. To analyfe this ore in the moift way, Mr. Bergman advifes to boil it after it is re- duced to a very fine powder in dilute nitrous acids, asinN0 8, and to edulcorate the refi- duum very carefully which contains the ful- phur and arfenic, which may be feparated by boiling in a fufficient quantity of aqua regia : if the fulphur ftill retains any luna cornua, it may be feparated by cauftic volatil alkali. 15. In the dry way it is reduced after tor- refaftion by a mixture of iron and lead ; the iron takes up the fulphur, and the lead the filver, which is afterwards feparated by cup- pellation. R 3 SPECIES 246 Elements of Mineralogy. SPECIES VI. Mineralized by Sulpur, and a very frnall For* tion of Arfenic and Iron. Slack Silver Ore. Schwartz ertz^ Schwartz gulden. Silber mulm. 16. This is either of nfolid and brittle con- fidence, which diftinguifhes it from the vitreous ore, and of a glafly appearance in its fra&ure when recent, or of a loofer texture, and footy or deep black colour, like mofs or thin leaves lying on the furface of other filver ores, or of thofe of lead or cobalt, or in clays, ponderous fpar, gneifs, &c. it may contain about 25 per cent, of filver : the former is found in Dauphine, Hungary, and Saxony^ and contains at moft 60 per cent, of filver. Mon. Mineral. 302. 3 Lin. von. Gmel. 406. SPECIES VII. Mineralized by Arfenicy and containing a large Proportion of Iron. Arfenicomartial Silver Ore, Weifs ertz. Py- rites Argenteus of HenckeL 17. Mineralogifts do not well agree about the ore to which this denomination belongs. I follow Mr. Monnety who feems to have at- tende^ Silver. 247 tended to the divifion of ores moft exactly. According to him this ore is a hard fubftance, of a white, fhining appearance, and of a compacl, lamellar or fibrous texture; the brighteft is the pooreft in filver; the richeft gives only 10 per cent, the pooreft 6 or 8 ounces : it contains no fulphur ; and hence Mr. Monnet calls it a metallic regulus, not confidermg that the iron is in a calcined ftate, which fully proves that arfenic is a true mi- neralizer: the iron and arfenic are in various proportions, but the arfenic always exceeds. It is fouad in Saxony, the Hartz, at t^ua- danal-Canal) &c. 1 8. It is eflayed in the moift way, as in Np-4. SPECIES VIII. Mineralized by Arfenic and Sulphur, ivith a fmall Proportion of Copper, and a Jiill fmaller of Iron. White Silver Orey Weifsgulden. 19. It is a heavy, foft, opake fubftance, fine grained or fcaly, bright and fhining in its fra6ltires, of a whitifh, fteely or lead co- lour, fometimes cryftalized in pyramidical or cylindrical forms, but often in amorphous grajns, or refembling rnofs, or in the form of R 4 thin 248 Elements of Mineralogy, thin laminae incruftating other bodies, foun4 in quartz, fpar, ftellftein, pyrites, blend, lead ore, cobalt ore, fparry iron ore, fluors, &c. It is very fufible ; its fpecific gravity 5,000 or 5,300; its proportion of filver from 10 to 30 per cent? 20. It is found, though not commonly, in Saxony , Hungary , the Hartz, and St. Marie ait*, Mines. 21. Mr. Bergman analyfes this ore in the following manner. Having pulverized and weighed a certain portion of it, he attempts its folution in about 1 2 times its weight of dilate nitrous acid : the copper and filver are diflblved, and a white refiduum remains. The filver he precipitates, not with marine acid, for this would unite alfp to the copper, and with the filver form a triple fait, which would alfo fall, but with a clean plate of copper previoufly weighed ; the filver being in its metallic form, may immediately be weighed, and its contents known : the cop- perfhould then be precipitated by aerated mi- neral alkali > 1 94 gr. of this precipitate well dried are equivalent to 100 of copper in its metallic form ; but from this laft, the weight, which the plate of copper loft, muft be fub- grafted. 22. The Silver. 249 22. The white refiduum, containing the fulphur, arfenic and iron, is next to be ex- amined : by boiling it in fpirit of fait, the arfenic and iron are taken up; the arfenic is to be precipitated by the addition of water, and then the iron by the Prujfian alkali ; the fulphur remains undiflblved, and may be treated with volatil alkali to try whether it retains any copper or horn filver. 2 Bergm. 418. SPECIES IX. Mineralized by Arfenic and Sulphur^ with a large Proportion of Copper andfome Iron. Grey Silver Ore, Fahl erz, 23. This is a hard, grey, or dark grey fub» ftance, more or lefs brilliant, fometimes cryf- talized, but moftly amorphous, and is, irj fa£l, the grey copper ore hereafter to be mentioned, Chap. 4. N°* 26, impregnated with filver, and varies much in its contents from about i to 12 per cent, of filver, and from 12 to 24 of copper, the remainder be-» ing fulphur and arfenic, with a little iron : the richer it is in copper, the poorer in filver, and reciprocally. Mr. Monnet remarks, that wherever copper is united to arfenic, filver is alfo found ; it is the comm:>neft of all the filver ores : the grey filver ore of Dal \i\ Elements of Mineralogy. contains alfo regulus of antimony, and, according to Mr. Bergman, it contains 24 per cent, of copper, and 5 of filver ; but this belongs to the next Species. SPECIES X. Mineralized by Arfenic and Sulphur -, with Cof- fer', Iron, and Regulus of Antimony. Brown Silver Ore, Leber erz. 24. Its colour is moflly of a reddifh brown, fometimes dark grey, fometimes it is found cryftalized in pyramids, but moftly amor- phous j when fcraped it appears red > it con- tains from i to 5 per cent, of filver ; the greateft part is copper, and the next in pro- portion is arfenic. It is found in Sweden, Germany and Spain. 25. It is analyfed by boiling it in about 6 times its weight of dilute nitrous acid, which will take up the filver and copper, and leave the regulus of antimony and arfenic : thefe being boiled in ftrong nitrous acid are de- phlogifticated, and the arfenic becomes foluble in water ; the c<*lx of antimony remains un- diflblved ; the fulphur may be found in a fecond experiment, ufmg aqua regia inftead of Silver. 25* of the concentrated nitrous acid ; the filver and copper are feparated as in N°* 21. SPECIES XI. Mineralized by Sulphur and Arfenic^ 'with Iron and Regulus of Antimony. Plumofe Silver Ore> Feder ertz. 26. In point of colour this ore varies from 3. dull white to grey, dark blue, brown or black ; it is found in a capillary form, or, like wool, fo.metimes loofe, at other times at- tached, its filaments are rigid and inflexible; the whiter it is, the richer ; but it feldom con- tains even i per cent, of filver. It is found in Saxony and elfewhere. Some confound it with the foregoing. Its analyfis may be imderftood from N°'. 21 and 25. SPECIES XII. tyLinera]ized by Sulphur and Arfemc-> 'With Cobalt and Iron. Cobaltlc Silver Ore. 27. This ore is diftingulfhed by rofe-co- loured particles, of cobalt difperfed through a dark brown, blackifli, or grey, and fome- what fhining folid mafs. It is found in Saxony i 352 Elements of Mineralogy. Saxony* and at Allemont in Dauphin^ and contains about 40 or 50 per cent, of filver, and very Httle cobalt j the arfenic is in an acid ftate, and united to the cobalt. 28. To analyfe it, let it be diffolved in nitrous acid ; the filver and cobalt will be taken up, and moft of the iron will remain cal- cined, together with the arfenic ; the filver may be precipitated by the marine acid, and the cobalt by an aerated fixed alkali, and its weight determined, as will be {hewn ia Chap. 13. SPECIES XIII. Mineralized by Sulphur, *wlth Regulus of An* timony and Barytes. Butter~milk Ore. 29. It appears in the form of thin pellicles, on granular fpar. SPECIES XIV. Combuflile Silver Ore. 30. This is black and brittle, and leaves about 6 per cent of filver in its afhes, it is a coal in which filver is found. The filver is extracted as ufual by nitrous acid. SPECIES XV, Silver. SPECIES XV. Mineralized by the Vitriolic and Marine ActJs, 'with a little Iron> and fomeiimes 'with a mixture of the Vitreous Ore. Corneous Sifoer Ore, Horn ertz. 31. This fcarce and valuable ore is of a white, grey, pearly, or yellow, green, brown, purple, or black colour, frequently cryftalized in a cubic form, fometimes refembling an. Earth, eafily fufible without any fmoke. The black fort is friable, and eafily pulve- rifed, but the other fort is in fome degree malleable, may be cut with a knife, and takes a fort of polifh when rubbed. The vitreous ore mixed with the black, is foluble in nitrous acid, and may by that means be feparatecj* the faline ores being infoluble in that acid ; if pure from iron, thefe ores fliould contain 70 per cent of filver at leaft, but they moftly contain fome portion of iron, of which foma is even united to the marine acid according to Monnet. It is found in Saxony^ Bohemia, S/v Marie aux Mines, Siberia^ and Peru. It was firft eflayed by Mr. Wolfe, Phil. Trans. 1776, and afterwards, though lefs exaclly, by Mr* Monnet, in 1777? fee 9 Mem. Etr. p. 717, 32. Mr, Elements of Mineralogy, 32. Mr. Bergman gives the following fhott ingenious method of anaJyling thefe ores in the moift way. i* He digefts this compound ore in th£ marine acid for 24 hours, by which means the vitriol of filver is decompofed, and the whole is converted into horn filver. He then judges of the quantity of the vitriol of filver, by the quantity of vitriolic acid let looft in the liquor, and to find how much this is, he decants the clear liquor, and drops into it a folution of nitrous barofelenite, which is immediately decompofed by the vitriolic acid, and forms true vitriolic barofelenite, of which 100 grains contain 15 of dephlegmated vitriolic acid, and fo in proportion* Now 100 grains of vitriol of filver, contain 25,37 of the fame dephlegmated acid, fo that 25,37 grains of this acid, indicate 100 of vitriol of filver, and fo in proportion, and thus the quan- tity of filver in the vitriol of filver is alfo found, as 100 grains of it contain 74,62 of filver,* and the proportion of vitrol of filver being known, that of horn filver of courfe, is known ; but if the ore be of the black kind, after the whole is turned into horn filver, it fhould be digefted in cauftic volatil , • * According to Mr. Bergman^ 100 parts of vitriol of filver, contain but 68,75 of filver. alkali, Silver. 255 alkali, which will take up the horn filver, and leave the vitreous ore. The iron, if any, fhould be precipitated from the firft folution, by the P ruffian alkali, after the pre- cipitation of the barofelenite. Uncertain Mineralizations. SPECIES XVI. Goofe-dung Ore. 33. This is of a greenifli colour, mixed with yellow and red ; it is faid to contain about 6 per cent of lilver. Some think it a mixture of red filver ore, and calx of nickel, SPECIES XVII. Fotiaceous Silver Ore. Silberartrges, Berg- zunder, Blatter erz. 34. Its colour is mortdore. It is thought by fome to be native filver, by others a mixture of galena, ochre, and filver, it is found in mountain cork, it is fo light, that it fwims on water. It contains but one ounce of filver per quintal. See Lehman's Experiments, Berl 1758, SPECIES XVIIL Elements of Mineralogy. SPECIES XVIII. Mineralized by Sulphur, Arfenic and BtfmutB. 35. Such ores have been talked of, but their exiftence has not as yet been proved. 36. Silver has alfobeen found in the fulphu- fated ore of zinc called pech blend, and in that of lead called galena, particularly the latter, alfo in the copper pyrites, but in fmall quan- tity, as fhall be mentioned in their proper places. 37. If an ore yields I per cent of filver, it is generally worth extracting. CHAP. IV. Copper. I. Its colour is pale red as is well known. Its fpecific gravity from 8,7 to 9,300, de- pending not only on its .purity, but alfo on its condenfation, by hammering. It is foluble not only in acids, but alfo in alkalis and neu- tral falts. It is precipitable from moft acids, in its metallic form, by a clean plate of iron, and moft of its acid folutions are con- vertible into a deep blue, by volatil alkalis. Thefe characters are fufficient to diftin- guifh it. SPECIES. L Copper. 257 SPECIES I. Native. d. Native copper, that is copper hi a more or lefs malleable itate, and either of its own peculiar, onof a grey or blackifh colour, has been found either in grains, or in large fhape- lefs folid lumps, or in a foliated, capillary, arborefcent form, or cryftalized in quadran- gular pyramids, in or on clay, fhiftus, quartz, fluors, zeolytes, &c. in Siberia^ Sweden^ Ger- ^ Hungary, Tranfyfoania, &c. 3. It undoubtedly has fometimes been pro- duced from precipitation by iron from wa- ters in which it was held in folution, and this is the purefl fort, but in many cafes it could not have been produced in that manner, and then this fort is never very pure, but mixed either with gold, filver, or iron, or with ful- phurs this laft combination forms what is called black copper* 4. All thefe impurities are difcoverable by folution, in nitrous acid ; the gold remains undiffolved in the form of a black powder, foluble in aqua regia ; the filver may be pre- cipitated by the marine acid, or ftill better by .a clean polifhed plate of copper, the iron is S feparated Elements &f Mineralogy. feparated by boiling the whole as it is dephlo* gifticated, and rendered thereby infoluble* Mineralized. 5. We may obferve in general, that all cop- per ores after roafting, communicate a blue colour to volatil alkali, on digefting them in it. Before roafting, it is poffible that arfenie may prevent that effeft, or even fulphur, if in fufficient quantity* SPECIES It. Mineralized by the Aerial Acid* Calciform Ores. % 6. Of thefe there are three varieties, the red, the green, and the blue, all are foluble in acids, and blacken in a moderate heat* I. VARIETY. Red, Minera cupri calciformis Rubra> M!ncra hep at ic a> Leberertz. 7. We fometimes meet with this ore in a loofe form, then called copper ochre, but generally it is moderately hard, yet brittle, fometimes cryftalized and tranfparent, either in a capillary formi or in cubes, prifms, or pyramids, Copper. byfarhicls : it is found in England, Scotland^ Germany, &c. it effervefces with acids. 8. According to Mr. Fontana, i i Roz. 51 1< ioo parts of it contain 73 of copper, 26 of fixed air, and i of water. Mr. Bergman ailfo found it to contain fixed air, 2 Bergm. 430. The brown, or hepatic ote, contains a vari- able proportion of iron or pyrites, and fome- times fulphurated copper, and hence affords from 20 to 50 per cent, of copper. It is often iridefceht; II. VARIETY. Green, Malachite, Mountain Green. 9. Malachite has the appearance of greert jafper, but is not quite fo hard, for it does not ftrike fire with fteel > it is either of a ra- diated or equable texture, generally of an oval form, and the fize of an egg, but fome- times it forms capillary filaments. Its fpe- cific gravity, according to Mufchenbroeck, is from 3,5 to 3*994; it is fometimes mixed with calcareous Earth and gypfunu It is found in Norway Siberia, &c< to. According to Mr. Font ana, ioo Parts of the pureft fort, contain ^5 of copper, and &5 of aerial acid and water. 82 i *. Mountain 560 Elements of Mineralogy. i r. Mountain Green, is generally found in a loofe and friable ftate, rarely cryftalized and indurated, often mixed with calcareous Earth and iron, andfome arfenic. 100 Parts of the pureft contain 72 of copper, 22 of aerial acid, and 6 of water. III. VARIETY. Mountain Blue, Chryfocolla of fame. 12. This alfo moft frequently appears in a loofe form, but fometimes indurated and even cryftalized, but it is then mixed with quartz. 100 parts of it contain about 69 of copper, 29 of aerial acid, and 2 of water. Mr. Morveaii) in the Memoirs of Dijon, for 1782, has fhewn, that the calces of copper are determined rather to a blue than a green colour, by a greater proportion of phlogifton. 13. They are analyfedin the moid way by folution in acids, and precipitation by the mineral aerated alkali, if they be pure, or by the PruJJian alkali, if they contain earths. 194 grains of the precipitate formed by the mineral alkali are equivalent to 100 of cop- per in its metallic ftate : fo alfo are 350 gr. of the precipitate formed by the Pruffian alkali, as Mr. Bergman has determined : copper alfo may be precipitated in its metallic ftate Copper. 261 date by means of iron, though it is not eafy to get it pure, if the nitrous acid be the folvent. 14. I have found that 112 gr. of good iron, precipitate 100 of copper from a faturate and dilute folution of it in the nitrous acid, and 80 gr. of the fame iron precipitate, 100 of copper from a faturate and dilute folution of it in the vitriolic acid ; fo that weigh- ing the iron before and after, the quantity of copper may be eftimated by the lofs of weight of the iron ; but care muft be taken that the iron do not remain in the nitrous acid after the copper is precipitated. Experience will point out fome other precautions too tedious to be inferted here. 15. If iron be mixed with the ore, it may be feparated by long boiling in nitrous acid. 1 6. In the dry way, after torrefaftion, they may be eflayed by melting them with I or I of their weight of borax, and 1 of their weight of pitch. Some lofs always attends the black flux. Thus Mr. Fontana having eflayed 576 gr. of a calciforrn ore by black flux, obtained but 376 or 380 of copper, yet by diftillation he got 408, u Roz. p; 511* S * SPECIES III. Elements of Mineralogy. SPECIES III. Cupreous Stones. Analogous to the calciform ores are the cupreous Hones, Turquoije and Lppis Ar- ineniis. 17. Turquotfe is the tooth of an animal penetrated with the blue calx of copper ; it lofes its colour when heated ; it is opake, and of a lamellar texture, and fufceptible of a fine polifh ; its fpecific gravity is from 2,5 to 2,908 ; fome are of a deep blue, fome of a yrhitifh blue, but become of a deeper when heated. This fton£ is found in Perfia and Languedoc. The copper may be extracted from it by diftilled vinegar. According to Reauinur, Mem, Par. 1715, nitrous acid will not diffolvethat of Perfia^ though it will that of France* which fhews a difference between them. 1 8. Lapis Armenus is another blue ftone; which does not admit of any polifh, and con- lifts of calcareous earth, or gypfum pene- trated with the blue calx of copper ; hence it fometimes effervefces witji acids, and fome- times not, but never gives fire with fteel ; \\ lofcs its colour when heated. i ....... . . ... SPECIES IV. Copper. 263 SPECIES IV. Mineralized by Sulphur withfcarce any Iron. Vitreous Copper Ore, Kupfer glafe ertz. 19. Its colour is red, brown, blue or violet ; It is generally fo foft as to be cut with a knife, and as to form, it is fometimes cryf- talized in regular figures, and fometimes amorphous; it is much more fuftble than pure copper ; its fpecific gravity is from 4,81 to 5,338. It is found in the mines of other copper ores, and in lime done, fpar, quartz, mica and clay ; it is the richeft of all the copper ores, and affords from 80 to 90 per ceqt. of copper, i o or 1 2 of fujphur, with a fmall proportion of iron ; the red ores are the pooreft, containing moft iron. 20. To analyfe this ore, Mr. Bergman ad- vifes a folution of it in 5 times its weight of concentrated vitriolic acid by ebullition to drynefs and the fubfequent addition of as much water as will diflblve the vitriol thus formed. This folution he precipitates by a clean bar of iron, and thus obtains the cop- per in its metallic form. If the folution be contaminated with iron, he re-diflblves thus the copper thus obtained, in the fame manner, and fo procures a richer folution, which he again precipitates with iron. 84 21. Dr, 264 Elements of Mineralogy, ii. Dr. Fordyce, in the PhilofophicalTranf* affions for 1780, fuggefts an improvement, by firft diffolving the ore in nitrous acid, and precipitating it by a fixed alkali (if this fo- lution be boiled, any iron it may contain will be precipitated) the precipitate he re-diflblves in vitriolic acid, and precipitates it with iron, 22. The proportion of fulphur may be found by diffolving the ore in dilute aqua re-* gia, as the fulphur will remain undiffolved. SPECIES V. Mineralized by Sulphur, 'with 20 -or 30 per cent, of iron. Azure Copper Ore, Kupfer Lazur, Kupfer malm. 23. This differs from the foregoing only in containing more iron; its colour confiftsin various {hades of blue, or reddifh blue j it is as hard, and much more brittle ; it contains from 40 to 60 per cent, of copper, from 20 to 30 of iron, and the remainder fulphur ; the poorer it is in iron, the richer in copper j it has been by many confounded with in- durated mountain blue^ SPECIES VI. Copper* 365 SPECIES VI. Mineralized by Sulphur, 'with a large Propor- tion of Iron. Telloiv Copper Ore, yellow Pyrites. 24. Its colour is yellow, or yellow mixed with red or green, or variegated like a pi- geon's neck ; it is moderately hard, not rea- dily giving fire with fteel as other pyrites do ; in its fra&ure it prefents lharp fragments ; it is fometimes found cryftalized, and fome- times amorphous ; its fpecific gravity is about 4, i 6 ; it occurs both in feparate mafles and imbodied in ftones, and is the commoneft of all the copper ores. 25. With refpect to its contents, the cryf- talized fort is the pooreft in copper, of which it contains only from 4 to 8 per cent, the re- mainder is chiefly iron \ it is generally reddifh, and is in facT: a martial pyrites, with a fmall proportion of copper ; the greenifh yellow con- tains moft fulphur, and from 1 5 to 20 per cent, of copper ; the pure yellow contains moft copper ; namely, from 20 to 30 per cent, its texture is foliated ; thefe pyritous ores al- ways contain argill, and a little of filiceous earth. SPECIES VIL 3 66 Elements of Mineralogy* SPECIES VII. Mineralized by Sulphur and Arfenic^ with <% little Iron. Arfenical OK grey Copper Ore. Kupfer, Jahl ertz, Weifs kupfer ertz. 2,6. This is of a white, grey, or brown colour; it is moderately hard, and very brittle, fometimes cryftalized, and1 often of a4n indeterminate figure; it is of very diffi- cult fufion, and heavier than the preceding. 27. It contains from 35 to 60 per cent, of copper 5 the brown is the richeft in copper ;. the white or grey contains moft arfenic; it frequently contains filver, and if this exceeds 3 or 2 per cent. it; is called greyjili)er It is found imbodied in all forts of ftones* and mixed with other copper ores as \yell as. with the ores of other metals* 28. The analyfis of thefeore-s in the moift way may be underftood from what has been already faid. To effay them in the dry way, they ihould firft be pulverized and feparated as much as poflible from ftony and earthy particles, then roafted to feparate the fulphur and arfenic, then melted with a mixture of an equal weight of Mr. Tilled flux, which confifta, popper. ponfifts of 2 parts pounded glafs, i of cal* cined borax, and 4- of charcoal : if the ore be poor more borax may be added ; black flux is hurtful, as it forms an hepar which holds part of the copper in fqlution. Mem, far- 1775- 29. Mr. Margraaf, in the Memoirs of Berlin for 1775* recommends a mixture of equal parts of clay well warned, fluor, and lime-ftone, and \ part of charcoal, with an equal weight of the torrefied ore ; the whole to be melted in a porcelain heat. The coal he ufes is that left after the diftillatiqn of tartar. SPECIES VIII. Mineralized by Sulphur and Arfenic, with Zinc and Iron. Blendofc Copper Ore. 30. Mr. Monnet fays he has met with this ore oply at Catharine berg in Bohemia ; Jt is of a brown colour, of a hard, folid, and compact granular texture ; it contains from 1 8 to 3® per cent, of copper. 31. It is analyfed in the liquid way by fo- lution in nitrous acid and precipitation of the popper by iron : the iron and zinc are preci- pitated 2,68 Elements of Mineralogy. pitated then by the Prujfian alkali ; the pre- cipitate calcined isre-diffolvedin nitrous acid, and the folution evaporated to drynefs ; the iron being thus deplogifticated becomes info- luble in nitrous acid ; the calx of zinc is re- diffolved in that acid, and again precipitated by the PruJJian alkali. 100 gr. of that pre-* cipitate wafhed and dried are equivalent to 20 of zinc in its metallic ftate, and 100 gr. of dephlogifticated iron are equivalent to 73,5 of iron in its metallic ftate. SPECIES IX. Argillaceous^ Sbiflofe^ or jlaty Copper Ore* Kupfer Schiefer. 32. This ore feems to confift of the vi- treous copper ore, intimately combined with fhiftus, and not barely difperfed through it; in vifible particles ; it is of a brown or black colour, lamellar texture, and very heavy ; it affords from 6 to 10 per cent, of copper, and is of difficult fufion, unlefs lime-ftone be added ; it contains a little bitumen, calcareous earth and iron, asjhi/tido. SPECIES X. Bituminous Copper Ore. Kupfer brand ertz. 33. This is faid to be found in Sweden -, it i* a fpecies of coal which gives little or no flame, Copper. 269 flame, but confumes and leaves afhes, from, which copper is extra&ed. SPECIES XL Copper in a foreign Form* 34. Animal and vegetable fubftances are fometimes found penetrated with copper. SPECIES XII. Mineralized by the Vitriolic or Marine Acids. 35. Thefe are mentioned and defcribed in the fecond part : in the dry way they are re-* ducible by Mr. Title t's flux. CHAP. V. Iron. I* Its fpecific gravity is from 7,6 to 8,0o? that of the moft dephlogifticated calx of iron, only 6,7. It is foluble in all acids, and the faturate folution precipitable by vegetable aftringents of a black colour* and by P ruffian alkali of a blue ; in its metallic or flightly de- phlogifticated ftate it is attraftable by the mag- net > it is the moft difficultly fufible of all metallic fubftances, except platina and man- ganefe. SPECIES L Elements of Mineralogy. SPECIES I. Native. 2. It is now known that native iron ex- ifts in many places, the moft remarkable mafs of this fort is, that difcovered in Siberia, ^vhich weighs 1600 pounds. It is of that fpecies called redjhort iron, being malleable while cold, but brittle when red hot. Pal- las Retfen, 3 TbelL p. 41 1< Mineralized. Calciform Ores. 3. The bafis of the calciform ores, is either tlie black or blackiih brown "calx of iron, which is in fome meafure phlogifticated and magnetic, or the red calx of iron, which i£ more dephlogifticated, and not magnetic be- fore torrefadion. SPECIES II. Jbroivn Calx of Iron, mixed 'with Iron in its metallic State. Steel Ore. Sfablerz. FerrumChalybeatum,Lin. Minera Ferrinigra. Cronft. §. 212. 4. Of a dark fteel colour, folid, compafi^ and finning in its ft adure 5 fcarcely gives fit 3 with Iron. 271 With fteel> gives a black powder, is magnetic, and in fome degree malleable when red hot. It affords from 60 to 80 per cent, of good iron. It is found at Adelfors and Danne*. mora in Sweden* alfo in the IJle ofElbe^ and North America. 5. Chryftalized iron ore in an o£tohoedral or cubic form, ferrum tejfulare> and miner a ferri cryfalizata of Wallertus^ belongs to this fpedes, it is fomewhat lefs magnetic, pro- bably becaufe it contains lefs of metallized iron. SPECIES III. Magnet. 6. This differs but little in its appearance from the preceding ore, but has lefs luftre ; it is either coarfe or fine grained, the coarie grained lofes its power fooneft. It feems to contain a fmall quantity of fulphur, as it fmells of it when red hot. It is probable that it contains more particles of iron in its metallic form, than the preceding ore, but it is often contaminated with a mixture of quartz and argill. It is poffible it may con^ tain nickel, for this when purified to a cer- tain degree, acquires the properties of a magnet, 2 Bergm. 242. Its conftitution has not as yet been properly examined. SPECIES { Elements of Mineralogy, SPECIES IV. Brown Calx of Iron, combined With Plum* bago. Black Eifen Glimmer^ Schwartz Eifen Rahm or Eifenman. y.This confifts of black fhining fcales, more or lefs magnetic ; Mr. Rinman found it to confiil of plumbago, and 26 per cent, of iron. Hijioria Ferri. §. 57. SPECIES V. feroivn Calx of Iron, united with the white Calx of Manganefe, and mild Calcareous Earth in various proportions. White or Sparry Iron Ore^ Weifs Eifen Spath$ Stahf/tein* 8. Its colour when frem dug is but by expofare to the air, it firft becomes grey, then brown, at laft reddifh, yellowim3 or black* Its fhape, either amorphous or fhomboidal, it is frequently tranfparent, its texture lamellar, fcaly, granular, or cellular* Sometimes it affumes a ftalaclitical form, and fometimes it is found in a powdery ftate, and is then of a brown blackifh colour, is fre- quently interfperfed with quartz and py- rites, Iron. 273 rites,&c.and does not give fire with fteel, unlefe thefe foreign fubftances be ftruck. Its fpe- cific gravity is from 3,6 to 3,895, or 4,00® it feebly effervefces with acids, particularly when pounded and heated, affords from 20 to 27 per cent of fixed air. It is fcarce ever magnetic before calcination, but if heated, it decrepitates, grows black, becomes mag- netic, and lofes from 15 to 40 per cent of its weight. 9. 100 Parts of this ore from Eifendrtz in Steria, afford according to Mr. Bergman, 38 of the brown calx of iron, 24 of the white calx of manganefe, and 38 of mild calcareous Earth. Another fort from Weft Silvretberg contains 22 of the brown calx of iron, 28 of the white calx of manganefe, and 50 of mild calcareous Earth. What quantity of iron and manganefe in a reguline ftate, thefe quantities of each calx would produce, may be feen by the table inferted at the end of this treatife ; the aerial acid is united not only to the Earth, but alfo to the metallic calces, as appears by its proportion. Many other ores are poorer, and fome to fuch a degree as not to deferve the name of an ore. It is fre- quently mixed not only with quartz and py- rites, as already mentioned, but alfo with fhoerl, zeolyte, mica or afbeftos. T When 274 Elements of Mineralogy. IQ. When this ore bears a ftaladlitical ap-? pearance, and is very white, it is called Jlos Jerri and eifen bluth : this affords 27 per cent. of reguline iron according to Mr. Rinman, and confecjuently 35 of the brown calx. SPECIES VI. Magnetic Sand. IT, That of Virginia, whofe colour is black, is of this fort j its fpecific gravity is 4,600, and it contains about I its weight of iron ; but its compofition has not yet been difcovered, SPECIES VII. fled Calx cf Iron indurated, and combined with a lit tie Argill, and frequently with Manganefc* Hematites. Glafs kopf. 12. It is generally of a red, yellow, purple, or brown colour, of a metallic luftre, and very hard, though feldom fo hard as to give fire with fleel ; when fcratched, it {hews a red trace ; it is not magnetic before torrefac- tion, but by that heat it becomes black and magnetic ; its ftru&ure is either folid, gra- nular, fcaly, or fibrous; it occurs either in {hapelefs Iron. . 27,5 ihapelefs mafles, or in a ftaladitical form, or even cryftalized in regular forms according to GmeHny though Mr. Ddljle denies it : in fome places it forms whole mountains ; it affords from 40 to 80 per cent, of iron. Ac- cording to Mr Gerhard it contains argill, for he extracted alum from it. Mr. Hklm found it alfo to contain manganefe. SPECIES VIII. Hematites In a loofe form, mixed with a notable Proportion of ArgilL H£ matitical yellow^ red and 6rown Ochres. 13. Ochres are diftinguifhed from clays by containing a larger proportion of martial particles ; thofe that become brown by calci- nation, and alfo magnetic, belong to this fpecies ; fometimes the ferruginous particles are mixed with argill, and calcareous or mu- riatic earths, and then thefe ochres effervefee with acids. SPECIES IX, Red Calx of Iron combined with Plumbago. "Red Eifen Glimmer, Eifenrahm and Eifenman. 14. This differs from the black in this, that it is not magnetic before tor refaction. T 3 SPECIES 3 76 Elements of Mineralogy. SPECIES X, Red Calx of Iron, mixed with a fmall Propar* tion of the bro and indurated. Torften. 15. This is of a bright bluifh black, or yellowifh grey colour, and fibrous texture, {hews a red trace when fcratched, and is ^yeakly magnetic before calcination. Ac- cording to Mr. Rinman it is lefs dephlo- gifticated than hematites. Hiftoria Ferri. §. 285. SPECIES XL Emery. 16. Emery feems to be a mixture of the red and white calces of iron, with fome un- known liony fubftance, perhaps tripoli ; it fcarcely yields in hardnefs to any fubftance, except diamond; the beft fort is of a dark grey colour, but becomes brown, and in great meafure magnetic by calcination ; other forts are of a reddifh rufty white, or yellowifh colour; its fpecific gravity is from 3,000 to 4.,ooo ; it is never ufed as an iron ore, nor is its proportion of iron well known. Iron. 277 SPECIES XII. Red Calx of Iron united to Siderite. Grey Iron Ore. 17. This has a fhining metallic appearance* and commonly gives fire with fteel ; it is not in the leaft magnetic, and when fcratched fhews a red trace ; it yields from 40 to 66 per cent, of coldjhort iron. 1 8. The ore called by the Swedes fmjlierne malm, or miner a fleiadum, is a mixture of the grey iron ore, with rhombic nodules of that delcribed in N°- 5. SPECIES XIIL Argillaceous Iron Ores. 19. Of thefe we may diftinguifh two prin- cipal varieties, namely, thofe found in mountains and high lands, and thofe found in fwampy grounds, or low lands overflown with water ; both are deftitute of metallic luftre, but very weighty, and fome of them when dry abforb water like clays. Tj I. VARIETY. 478 Elements of Mineralogy. I. VARIETY. High land Argillaceous Ores. Miner a fern Ochracea. 20. Thefe are either yellow, red, brown> or greyifh, indurated and friable, or loofe and powdery, or in grains ; they confift chiefly of the red or yellow calx of iron, or of the grey iron ore, or torjlen in a loofe farm, mixed with argill or clay, and confe- quently often contain manganefe, or fideritey and fome, particularly in France, and the neighbourhood of Liege , are faid to contain the calx of zinc. Hence there are many varities of them, and their yield of iron, as well as its qualities, are very different : they do not effervefce with acids, (unlefs calca- reous or muriatic earth be cafnally mixed with them,) and are difficultly foluble in them; the rnoft foluble are the beft; they never obey the magnet before calcination, and rarely after it. 21. Horn-ftone over- loaded with iron be- longs to this fpecies. 22. Mr. Rinman mentions a 'white iron ore found in Kenty mixed with clay or marl, %hich affords 47 per cent, of brittle iron, and Iron. 279 and is fcarcely foluble in acids* Hiftor.ferri* P- 733- II. VARIETY. Sivampey Argillaceous Ores* Mnera ferri Lacuftris ve! fubaquofa. Mine defer Limoneuse. 23. When dry, this ore is friable, and brown, or brownifh black, and appears either in Jumps of an irregular fhape, or in round balls porous or folid, or in flat round pieces, or in grains, and fometimes in (lender trian- gular prifms parallel to each other, and very brittle. It is mixed with argill and ex- tractive matter, and becomes magnetic after calcination, by which operation it lofes about J of its weight, and the greater part of what, is thus volatilized is water, the remainder aerial acid and volatil alkali. The crude ore affords about 36 per cent, of regnlus, and after calcination about 50 per cent, it is the chief matrix of fiderite, and the iron pro- cured from it is coldfhort^ at leaft in Sweden. The iron of Hufaby^ of which Mr. Bergman treats in his analyfis of iron, • is drawn from this ore. Mr. Hielm has found fome forts of it to contain 28 per cent, of manganefe. T 4 SPECIE 280 Element* of Mineralogy. SPECIES XIV. Red Calcareous Iron Ore'. 24. This is found in a loofe form in many 'parts of England ; it effervefces ftrongly with acids, and is ufed as a pigment. SPECIES XV. Siliceous Iron Ore. 25. Befides jafper, garnet and trapp over- loaded with iron, there is found, principally in France^ a black, heavy, unmagnetic fand, of the filiceous kind, which is faid to contain iron and zinc in great quantity. 26. Baron Born, in his letters from Hun- gary, mentions a blue cryftalized iron ore, which he fays is a fhoerl overloaded with iron. SPECIES XVI. Muriatic Iron Ore. 27. Serpentine overloaded with iron forms this fpecies, but it is feldom worked. SPECIES XVII. Martial Calamine. 28. Calamine is properly an ore of zinc, but fometimes it contains fo large a propor- tion Iron. 281 tion of iron as to be worked with a view of obtaining this metal ; it confifts of a mixture of quartz and argill, with the calces of iron and zinc ; its colour is yellow, red, or brown, and it is moderately hard. SPECIES XVIII. Mineralized by Sulphur. Martial Pyrites, 29. Thefe are ftony concretions of ful- phur, clay, and calx of iron, fo hard as to give fire with fteel. There are two prin- cipal varieties of them. I. VARIETY. Pale yellow Pyrites. 30. This has been already defcribed among the ores of alum, II. VARIETY. Brown or reddifo brown Pyrites. Miner a fern be pat ic QI Waffer kiefs. 31. It is generally of a fpherical ihape, or cryftalized in cubic, rhomboidal, or other po- lyhedral forms, and is devoid of metallic luftre ; it difficultly gives fire with fteel, and contains very little fulphur, but much more iron Elements of Mineralogy. iron than the yellow pyrites, and not unfre- quently a mixture of calcareous Earth. It » fometimes magnetic before, and always after calcination. It is incapable of vitrioli- nation. The iron it affords is brittle. SPECIES XIX. Mineralized by Sulphur and Arfenic. White, Grey, or Bluifh grey Pyrites , Marcaffiic Raitjh gelb kiefs, Gijt kiefs, Arfenic Stein. 32. It is found either in folid compact fnafles of a moderate iize, or in grains, it gives fire with fteel ; when burnt, it affords a blue flame, and an arfenical fmell, and by diftillation, orpirnent, or realgar, it is not magnetic, either before or after calcination, it contains much more of arfenic than of fulphur. It is analyfed by digeftion in ma- rine acid, to which the nitrous is gradually added, otherwife the fulphur would be deftroyed. See N? 34. SPECIES. XX. Mineralized by Arfenic fingly. Mifpickel. Speifs of the Bohemians. 3 5. Its colour is generally of a bright white, fefembiing a mixture of filver and tin, rarely variegated 283 Variegated like a pidgeons neck, and is not eafily altered by expofure to the air. Its form either -granular, cufpidated, cuneiform, prif- rnatic or rhomboidal. It is magnetic neither before nor after calcination, is foluble in acids, affords arfenic by diftillation, in the propor- tion of 30 or 40 per cent, and fometimes con-* tains a fmall proportion of copper and filver, It is frequently mixed with other metallic ores, and often found in indurated clay, quartz, fpar, fhoerl, &c. 34. When iron contains lefs than T'^ of arfe- nic, it is magnetic, Scheff. §. 300, therefore if the calcination be puftied fo far, the iron will remain magnetic. It may be analyfed by folution in the marine acid, which will take up the iron and leave the arfenic, or by fo- lution in aqua regia, which will take up both, but water being added, will precipitate the arfenic and leave the iron. The iilver will remain in the form of horn filver, and the copper may be feparated by the methods already mentioned.' SPECIES XXL / Combujllble Iron Ore. i 35. Of this kind Mr. Cronjled mentions two varieties, one, of which the greater part is 284 Elements of Mineralogy. is volatil, in a ftrong heat long continued, and feems to contain iron, plumbago, and coal intimately mixed. The other burns with a languid flame, lofes about 4. of its weight, refembles pit-coal, but is fomewhat harder, and yields about 30 per cent of iron. SPECIES XXII. Mineralized by the Vitriolic Acid. 36. This has been mentioned under the head of faline fubftances. Uncertain Mineralizations. SPECIES XXIII. Iron Blende. 37. TThls is faid by Mr. Monhet to be a ftone of a grey iron colour, formed of di- verging laminae, of great hafdnefs and a metallic appearance, but infoluble in acids, and infufible in the ftrongeft fire, Mineral. 356. Sometimes this ftone contains arfenic, in this cafe it blackens by expofure to the air. SPECIES XXIV. Wolfram. 38. This flone which is generally found in tin mines, is of a black or brown fhining colour, Iron. colour, of a radiated or foliated texture, of a moderate hardnefs, and fometimes fo brittle, as to be eafily broken between the fingers, but very weighty fince its fpecific gravity is 7,119 ; when fcratched it fhews a red trace, which diitinguiflies it from tung- ften. It is fcarcely folubb in acids, and of very difficult fulion. According to, Lehman* it confifts of filiceous Earth, calx of iron, and a fmall proportion of that of tin, Chym. Schrift* 356, and from his experiments, I am incli- ned to think it contains manganefe. SPECIES XXV. Native Prujfian Blue. 39. It confifts of play mixed with iron, and fome unknown tinging fubftance, gene- rally found in fwampy grounds or bogs. It is at firft white but when expofed to the air, it becomes either of a light or deep blue. When heated, it turns greenifh, and emits a flight flarne, and then becomes red and magnetic, it is foluble both in acids and Alkalis, but the latter precipitate it from the former, and the former from the latter ; the precipitate is at firft greenifli, but gra- dually aflumes a white hue, but recovers its falue tinge if it be fteeped in vegetable aftrin- gents, Ber^m. Sciagr. §. 206. Phil* Tranfi 1768 286 Elements of Mineralogy. 1768. The Earth of Beuthnitz in SHe/ia* mentioned in the Memoirs of Berlin for the year 1 757, feems to belong to this fpecies, it contains about -^ of its weight of iron. SPECIES XXVI. Green Earth of Verona and Normandy. Terre Verte. 40. This is ufed as a pigment, and contains iron in fome unknown ftate, mixed with clay, and fometimes with chalk and pyrites; allum and feienite arealfo accidentally found with it. It is difficultly foluble in acids, is not magnetic before calcination, and becomes of a coffee colour when heated. It is faid to afford about 40 per cent of iron. If iron be precipitated from vinegar, by the arfenical acid, the precipitate will be green, 36 Mem. Stock, and it will preferve its colour though expofed to the air. Iron precipitated from the marine acid by lime water, is frequently green, and green fluors are known to derive their colour from this metal. The molyb- denous acid gives alfo a green colour to iron, but this fades, Of Iron, Qf the Analyfis and EJJay of Iron Ores, In the moijt Way. 41. The general method of analyfing in the moift way the calciform ores, which do not contain much earth or ftony matter, is, after reducing them to a fubtil powder, to diflblve them in the marine acid, and preci- pitate them by the PruJJian alkali ; the quan- tity of alkali ufed difcovers that of iron in its metallic ftate, which the ore would afford, as already mentioned in the analyfis of earths, or the precipitate warned and dried may be weighed ; its weight divided by 6 (fubtrad:- ing 4 per cent, for the iron already contained in the alkali) gives the quantity of iron in its metallic ftate which the ore contains. But if the iron be united to any confi- derable proportion of zinc or manganele, its eftimation by the above methods is not fuSU ciently accurate ; therefore the P ruffian blue muft be calcined to rednefs, and the calx treated with dephlogifticated nitrous acid, which will then take up only the calx of zinc : when this is feparated, the calx mould be again treated either with nitrous acid, with the addition of fugar, or ftill better, with the acetous acid, either of which will feparate f he manganefe, if any ; the remaining calx 288 Elements of Mineralogy. of iron may then be diflblved by the marine, and precipitated by the mineral alkali, Of it may be further calcined, and then weighed. The annexed tables fhew the correfpondence betwixt the weight of the calx, or the precipi- tates with that of iron in its metallic ftate. See alfo Chap. 15. N°- 18. 42. To analyfe the 'white calcareous iron cre> it fhould be firft calcined to find the weight of the fixed air and water, then thrown into dephlogifticated nitrous acid, and fhaken for a few minutes until the menftruumt begins to acquire a yellow colour ; it will then contain the calcareous earth only, which may be precipitated by the mineral alkali, and weighed; the refiduum well calcined may be treated with the acetous acid as above. 43. According to Mr. Rlnman, the con-* tents of this ore may be conjectured very nearly from its fpecific gravity ; for as 80 is to i oo, fo is the fpecific gravity of this ore to its contents per cent. 44. The pyritous, argillaceous and ftony ores are analyfed by folution in marine acid, to which, if neceffary, a little of the nitrous may be added : this digeftion fhould be continued as long as the menftruum acquires a yellow Iron. 289 a yellow colour ; co&ion may be requifite at the end. 45. Many ores, which are difficultly fo- luble before calcination, become eafily foluble after they are calcined. 46. To difcover fiderite in an ore, it fhould be diflblved in dilute vitriolic acid 3 the folu- tion, after ftanding fome hours, will depofit a white calx, if fiderite be contained in it. In the dry Way. 47. Mr. Morveau recommends the follow- ing flux for all iron ores: 8 parts pulverifed glafs, i of calcined borax, and { of charcoal, well mixed j of this flux he takes two parts, or, if the ore be very poor, 3 parts, and i of the ore, and places them in a crucible, lined with a mixture of a little clay, and pounded charcoal |- of an inch thick, to which a cover is luted : this he places in a fmith's forge, and urges it with a ftrong heat for half an hour ; to find whether the ore requires calci- nation, he inftitutes this trial with equal weights of the ore calcined and uncalcined, and compares the refults ; the weight of the ore fhould not exeed 60 grains. 48. Mr. Bergman efiay s the white fparry iron ore by placing it in a crucible lined with char- U coal Elements of Mineralogy^, coal i an inch thick at bottom, and ~ on the fides, fimply covering it with calcined borax, luting on this another crucible, which healfo expofes to the heat of a fmith's forge. 49. Argillaceous and filiceous iron ores rnay be eflayed in the following manner: take of the ore 4 parts, quick lime 1525, fluor fpar 1,25, powdered charcoal i, decre- pitated common fait 4 ; the whole, being well mixed, place in a crucible lined with charcoal, to which a cover fhould be luted* and the lute being dry, commit it to a fmith's forge, giving a moderate heat for J of an hour, and the ftrongeft for the re- mainder of the hours if the lime be flacked, double the quantity muft be ufed. 6 Crcll. Nev. Entdeck. 50. Calcareous ores may be treated in the fame manner, except that inftead of quick lime double the quantity of fluor mould be ufed. 51. Pyritousores are alfo eflfayed nearly in the fame manner ; the proportions being 4 parts of the ore previoufly roafted, 2 of quicl^ lime, 2 of fluor, if of charcoal, and 4 of decrepitated common fait. Ibid. 52. Iron ores, which, though at firft bright in their frafture, foon grow black by expofure to the air, contain much man- ganefe. 53- Tin. 291 53. To find whether iron or its ore con- tains manganefe, let a fmall quantity of it be heated white in a crucible, and on this project 5 times its weight of purified nitre, taking care that no coal or aflies fhould get into the crucible : when all is cold, the upper part of the crucible will be covered with a greenifh or bluiih cruft, if the iron contain manganefe. 3 Bergm* 66. When the folu- tion of iron in the marine acid is of a red colour, this alfo denotes the prefence of manganefe, though that colour foon changes to a yellow, by extracting phlogifton from the martial part. 54. Mr. Bergman gives alfo a method of finding whether the ore affords coldfhort or redihort iron. He melts the regulus ob- tained from the ore with J of its weight of good malleable iron in a crucible lined with charcoal, and well covered. If the regulus thus obtained be brittle when cold, the ore affords coldfhort iron, or if it cracks under the hammer in a white heat, it is redfhort, 3 Bergm. 46, CHAP. VL Tin. i . The colour of tin is too well known to qeecl being defcribed ; its fpecific gravity is U 2 fro*} 292 Elements of Mineralogy, from 7 to 7,45 ; the lighteft is the pureftj it melts the moft readily of all metals ; it i$ eafily diflblved in fpirit of fait or aqua regia, and its folution is precipitated blue or purple \>j that of gold. SPECIES I. Native. 2* The exifterice of native tin has long been queftioned, but it has undoubtedly been found fome years ago in Cornwall in the form of thin flexible laminae iffuing out of a ma- trix of quartz, or regularly cryftalized. Phil. Tranf. 1766. p. 37. and Mr. ^uift9 a very competent judge, attefts its purity in the Memoirs of Stockholm for the fame year. 3. To afcertain its purity, Mr. Bergman advifes dephlogifticating it by the nitrous $cid. 140 gr. of this calx wafhed and dried are equivalent to 100 of tin in its metallic form ; the folution will take up the copper, and a fmall proportion of iron which the tiq, may contain, and thefe again may be fepa- rated by boiling ; if there be any arfenic, it wi}l be found in the walhings. SPECIES 293 SPECIES IL Calciform Ores. 4. Thefe ores are remarkable for their great weight, their fpecific gravity being from 5,955 to 6,75 : they may be reduced to 4 Varieties. I. VARIETY^ Tin Spar, white Tin Ore* 5. It is generally of a whitifh or grey CO* lour, fometimes greCnifh or yellowifh, femi- tranfparent and cryftalized in a pyramidical form, or irregularly : it was formerly thought to contain arfenic 5 but Mr. Margraaf found it the pureft of all tin ores, i Margr, 188,, 189, though it is faid to contain fometimes a mixture of calcareous earth j its fpecific gra- vity is 6,007* II. VARIETY. Opakej broivn or black Tin Ore. 6. This is alfo cryftalized and imbodied in a ftony matrix of quartz, fluor or mica, or mixed with white or yellow pyrites, or in ores of lead or zinc, cobalt, wifmuth or iron; when thefe cryftals are large, they are called by the Germans zingraupen> and when fmall U 3 zin ft 94 Elements of Mineralogy. xin zwltter ; the black are reckoned the rich- eft, and afford about 80 percent, of tin ; they all contain a mixture of iron. 7. The ore called iveifs zingraupen is that which was mentioned under the calcareous genus by the name of tungften ; it contains no tin. When any arfenic is found in tin, it proceeds from the matrix, for tin itfelf is never mineralized by it ; and for the fame reafon zinc is fometimes found in tin. 8. The fpecific gravity of this ore is 6,75. Mem. Stock. 1778, p. 321. III. VARIETY. Reddifh or reddijh yellow Tin Ore, Garnet Tin Ore. 9. This confifts of fmall cryftals femi- tranfparent or opake, and fometimes it is found of a fpherical form, ftriated, and re- fembling haematites or zeolyte; its fpecific gravity is from 5 to 5,8 j it contains more of iron than of tin. IV. VARIETY. Tin Stone> Zinjlein of the Germans^ Tinberg of the Swedes. 10. The preceding varieties confift for the moft part of metallic particles ; the prefent, chiefly Tin. 29J thiefiy of fiones or fands of different forts, which contain calx of tin invifibly diflemi- hated through them ; their fpecific gravity^ when the proportion of tin is of any im- portance, is confiderable j they may be of any colour, blue, grey, black and brown are the commoneft 5 they are called Lode/lones. 12. Tin ores are very fcarce, not being hi- therto found in any confiderable quantity, ex- cept in the Eaji Indies^ Cornwall, Bohemia and Saxony. 1 3. It is remarkable that tin has not as yet been found in any ftones of the calcareous genus, except fluors, but only in thofe of the filiceous or agillaceous kind. SPECIES lit. Mineralized by Sulphur. 14. This was lately difcovered by Mr. Bergman among fome minerals which he re- ceived from Siberia. He obferved two forts of it analogous to the two artificial combina- tions of tin with fulphur ; one nearly of the colour of zinc, and of a fibrous texture, which contained about twenty per cent, of fulphur, and the remainder tin 5 the other inveloped the former like a cruft, refembled aurum mu- and contained about ^o per cent, of U 4 fulphur Elements of Mineralogy. fulphur, a finall proportion of copper, and the remainder tin. Mem. Stock. 1781, p. 328. 15. To efiay tin ores in the liquid 11^7 has hitherto been thought imprafticable ; how- ever, Mr. Bergman has devifed the following method, which is generally fuccefsful. Let the tin ore, well feparated from its ftony matrix by wafhing, and reduced to the moil fubtile powder, be digefted in concentrated oil of vitriol in a ftrong heat for feveral hours, then when cool add a fmall quantity of concentrated marine acid, and fuffer it to ftand for one or two hours ; then add water, and when the folution is clear pour it off, and precipitate it by fixed mineral alkali. 131 gr. of this precipitate wafhed and dried are equivalent to 100 of tin in its reguline ftate, if the precipitate confifts of pure tin ; but if it contains copper or iron, it ihould be calcined for one hour in a red heat, and then digefted in nitrous acid, which will take up the copper, and afterwards in marine acid, which will feparate the iron. 1 6. In the dry ivay^ thefe ores, after pul- verization and feparation of the ftony matter by wafhing, are to be melted with a mixture of double their weight of a flux, confifting of equal parts of pitch and calcined borax, in a crucible "Lead. 297 crucible lined with charcoal, and to which a cover is luted 5 fufion fhould be fpeedily procured. 17. Mr. Bergman recommends a mixture of one part of the ore with two of tartar, i of black flux, and i part of rofm : this is to be divided into three parts, and each fuc- ceffively projeded into a crucible heated white, and immediately covered after the foregoing portion ceafes to flame ; the whole operation takes up but 7 minutes or lefe. Stc/. §. 304. CHAP. VII. Lead. 1. This metal is fufficiently diftinguifhable by its colour, which is well known, its fpecific gravity, which reaches from 11,3 to 11,479, its great foftnefs and eafy fufibility. It is more or lefs foluble in all acids, and particu- larly in the nitrous, and all its folutions have a fweetifh tafte, it is precipitable from the nitrous by the vitriolic or marine, and from the marine alfo, by the vitriolic. SPECIES I. Native Lead. 2. It is faid to have been found in Mon- mouth/hire Elements of Mineralogy. mouth/hire in fmall pieces, Phil. Tranf. p. 20, alfo in th£ Vharais, Genfanne hiji. guedoc, vol. 3. p. 208. Henckel alfo men- tions it in his Flora Saturnifans. If it con- tains copper, this latter may be detected by a plate of iron immerfed in its folutio'n in nitrous acid, and the prefence of filver, if any be contained in it, will be difcotfered by a plate of copper. SPECIES II. Mineralized by the Aerial Acidi Calciform 3. Of thefe we may diftinguim 5 varieties,' all eafily foluble in nitrous acid, and with efFervefcence if heat be ufed, and alfo in exprefled oils ; all contain a little iron, but Jiever filver. I. VARIETY* White, Lead Spar, Lead Ochre, Native Cerufs. 4. Lead Spar is fometimes tranfparent, but generally opake, and cryftalifed in regular forms, of a laminar or ftriated texture. Lead ochre, or native cerufs is the fame fubftance, but in a loofe form., or indurated and fhape- lefs j fometimes it is found in a filky form. Both contain a little iron, and fometimes calcareous Lead. 299 calcareous earth and argill. Jacquirts Mifcell. 157. 3 Roz. 348. both grow red or yellowifh when fufficiently tieated. They effervefce with acids, and afFord from 60 to 80 or 90 per cent, of lead ; both are found in Brittany '9 Lorrain, Germany, and England. II. VARIETY. Red, Bro Vitreous Zinc Ore, Zinc Spar. 4. Of a whitiih, grey, bluifh grey or yel- lowifh colour, and of a hardnefs. generally fufficient to ftrike fire with Heel ; in its frac- ture it refembles quartz, amorphous, ftalac- titical or cryftalized in groups, and weighty; by calcination it lofes y of its weight, with- out emitting a fulphureous or arfenical fmell, and is infufible in the ftrongeft heat either fmgly or with mineral alkali, but eafily fufible with borax or microcofmic fait. In the mineral acids it is foluble with effer- vefcence, and with the vitriolic affords vitriol pf zinc. ioo gr. of this ore contains about 3 1 4 Elements of Mineralogy. 65 of the calx of zinc, 28 of aerial acid, 6 of water, and i of iron, and fometimes a little of filex. 2 Bergm. De Mm. Zinci. 5. Note, Mr. Bergman fufpedls the fub- ftance called zinc fpar by Baron Born to be a different fubftance. Mr. Bindheim found it infoluble in acids before calcination, and in the dry way infufible with the three ufual fluxes, but after calcination it becomes fo- luble in acids. 4 Berlin Scbriff* 399, II. VARIETY. Mixed ivith a notable Proportion of Iron. Tutenago. 6. Mr. Engejlroni) in the Memoirs of Stock- holm for the year 1775* has given us an ana- lyfis of an ore of this fort from China ; it was of a white colour, interfperfed with red ftreaks of calx of iron, and fo brittle as to be eafily broken betwixt the fingers ; in the dry way it exhibited the fame appearances as the former Variety* except that it loft no part of its weight ; it was foluble in the mineral acids, particularly with the afTiftance of heat, and with the vitriolic afforded vitriol both of zinc and iron ; the quantity of fixed air was fo fmall as to be abforbed by the folution ; it contained ia various fpecimens from 60 to 90 per Zinc. 31$ per cent, of zinc ; the remainder was iroa and a fmall proportion of argill. Mr. Bind- heim alfo difcovered this Variety in Germany^ and found it to confift of zinc, a little iron and filex. 4 Eerh Schrifi. 400. III. VARIETY. Mixed ivith Iron and Clay in various Pro- portions. Calamlne, 7. Its colour is white, grey, yellow, brown or red, not fo brittle as the 2d Variety, and of various degrees of hardnefs, though fcarce ever fo hard as to ftrike fire with fteel ; its texture equable or cellular, and its form either amorphous, cryftalized or ftaladitical ; when calcined it lofes no part of its weight, except it be mixed with charcoal, and then flowers of zinc fublime ; it is foluble in acids, and with the vitriolic affords vitriol of iron as well as of zinc, which {hews the iron it contains is not much dephlogifticated. The fpecific gravity of the beft fort, that is, the grey, is 5,000: 100 parts of this afforded jidr, Bergman 84 of calx of zinc, 3 of iron, i of argill, and 12 of filex; but in other fpecimens thefe proportions are very different; ores are fo poor as not to contain above 4 3i 6 Elements of Mineralogy. 4 per cent, of calx of zinc; a good orefhould afford at leaft 30 per cent, and its fpecific gravity be about 4,400 or 5,000. 8. Sometimes calamines contain a mixture of calcareous earth and lead. 3 Lin. effervefcence arifes. Its fpecific gravity is from 3,706 to 5,0005 it is foluble in about 70 or 80 times its weight of water in the temperature of 60, or in 15 or 20 times its weight of boiling water ; the folution turns tincture of turnfole red, and fyrup of violets green ; it is fcarcely foluble in the vitriolic acid, fomething more in the marine, and mod perfectly in the nitrous di- luted ; when in a powdery form, it is called Jlos arfenici, and has been often taken for a calcareous earth. 6. White pyrites, which confifts- of the calx pf arfgnic, mixed with fulphurated irpn, has been 330 Elements of Mineralogy. been defcribed among the iron ores. Spe- cies 19. SPECIES III. Mneralized by Sulphur. 7. Of this there are two Varieties, the yellow and the red ; both are fublimable in clofe veflels, detonate with nitre, with fixed alkalis form a hepar, and are foluble in oils. I. VARIETY. TclloiV) Orpiment. 8. This is rarely found cryftalized. Baron Born once found it in a polyhasdral form in a blue clay in Hungary ; it is generally com- pofed of fhining, flexible laminse like mica, more or lefs folid ; its fpecific gravity is about 3,315; it contains only about ~ of its weight of fulpfiur ; it burns with a blue flame, II. VARIETY. Red,- Realgar^ Raufchgelbe. 9. It is found either in fhapelefs or ftalacli- tical mafles, opake or femi-tranfparent, or tranfparent and regularly cryftalized in odlo- haedral pyramids or prifms, and then called ruby of arfenic\ its fpecilic gravity is 3,225, 100 Regulus of Arfenic. 331 100 parts of it contain 16 of fulphur; ni* trous acid foon deftroys its rednefs, 10. To analyfe thefe ores, they fhould be digefted in marine acid, adding the nitrous by degrees to help the folution ; the fulphur will be found on the filter ; the arfenic will remain in the folution, and may be precipi- tated in its metallic form by zinc, adding fpirit of wine to the folution. 2 Bergm. 442. SPECIES IV. Calx of Arfenic djffufed through Earths or Stones. 1 1 . Henckel mentions a grey or bluifh marl in which this calx was found ; clay and cal- careous ftones are alfo fometimes impregnated with it $ it is difcovered either by the fmell when laid on burning coals, or by lixiviation. 12. In the dry 'way calx of arfenic isfepa- rated from the ores which contain it by fub- limation in a well luted retort, and a gradual heat, but fome always remains, which cannot be expelled but by an open fire and the addi- tion of charcoal. 13. White arfenic, that is, calx of arfenic, is reduced to a regulus, either by quickly melting it with a mixture of 2 parts foft foap, 33* JLhmtnis of Mineralogy. foap, and two parts of mineral alkali, pouring it when in fufion into a hot iron cone, or by mixing it with oil to the confidence of a fyrup, and then with a gradual heat diftilling the whole to drynefs ; towards the end the regulus fublimes, and may be made more perfect by a fecond diftillation with its own weight of oil ; by reafon of the offenfive fmell the diftillation ihould be m^de in the open air. CHAP, XII, Bifmuth. 1. Bifmuth is of a reddifh or yellowifh white colour, of a lamellar texture mode- rately hard, and brittle ; its fpecific gravity exceeds that of any of the femi-metals, or even moft of the intire metals, yielding only to that of platina, gold, jnercury, lead and filver, being from 9,600 to 9,700 ; its fufi- bility is nearly as that of lead \ \\ is eafily foluble in nitrous acid or aqua regia, but fcarcely in the vitriolic, and ftill lefs in the marine ; its folution is colourlefs, and is pre-s cipitableby the addition of pure water. 2. 113 grains of this precipitate from nitrous acid, well walhed and dried, areequi- t to 100 of bifmuth in its metallic forip. SPECIES. I. Bifmuth* 333 SPECIES L Native. 3. This is the commoneft of all native me- tallic fubftances* and is generally found either in cubes or odagons, or of a dentritical form* or in that of thin laminae inverting the ores of other metals, particularly thofe of cobalt, from which it is eaiily diftinguifhed and fepa- rated by its great fufibility ; it is faid to be fometimes alloyed with filver ; if fo, they are eafily feparated by folution in nitrous acid, and the addition of water, which precipitates only the bifmuth, and leaves every other metal in the folution. SPECIES IL Mineralized by the aerial Acid. Native Calx of Bifmuth. 4. When pure it is of a yellowilh white colour, and either in a powdery form, or in- durated like mortar ; but it is frequently of a greenifh yellow colour, being mixed with ores of other metals ; the red and yellow part is moft commonly cobalt ore, though it has often been miftakenfor bifmuth ; it is fre- quently found in glittering particles interfperfed through ftones of various kinds j filver, iron, and other rnetals are alib found in it; frorn 334 Elements of Mineralogy. all which it is feparable by folution in nitrous acid, as before explained. Mineralized by the vitriolic Acid. Wifmutb Bluth. 5. This is faid to be of a yellowifh, red- difh, or variegated colour, and to be found mixed with the calx of bifmuth, incrufting other ores. Veltheim Grundrifs. Mineralized by Sulphur. 6. It is chiefly found in Sweden, is of a bluifh grey colour, lamellar texture, and tef- fellar form like galena, but much heavier ; it fometimes prefents parallel ftriae like anti- mony, and its colour is variegated ; it is faid to contain befides bifmuth alfo cobalt and arfenic. 3 Lin. von Gmelin, 133. This ore is very fufible, and the fulphur moftly fe- parates on fcorification ; it is foluble in nitrous acid, and is analyfed like the foregoing ores. Mineralized by Sulphur with Iron. 7. This is faid to be of a lamellar cunei- form texture, and to be found in Norway. 8. In the dry way bifmuth is extracted from its ftony ores by mixing 2 parts of the pulverized Cobalt. 335 pulverized ore with i of pounded glafs, and i of calcined borax, melting the whole in a crucible lined with charcoal. CHAP. XIIL Cobalt. 1 . Cobalt, or regulus of cobalt, as it is called by fome, is of a bluifh grey colour, very hard, brittle, arid fteel grained ; its fpe- cific gravity is about 7,700; its fufibility is nearly as that of copper ; it is difficultly cal- cined, and its calx is of a blue, fo deep as to appear almoft black; and this calx melted with borax, or potafh and white filiceous fand, gives a blue glafs : this calx is not vo- latil ; the regulus is eafily foluble in fpirit of nitre or aqua regia, and the colour of the fo- lution is red, but difficultly in the vitriolic and fcare at all in the marine acid j the calx is more eafily diflblved by thefe acids ; it yields even to the acetous. SPECIES I. Native. 2. This has not as yet been found ; that which pafles for fuch is mineralized by arfenic. SPECIES 336 Etemehts of Mineralogy. SPECIES II. Mineralized by the aerial acid. Stack Ochre of Cobalt, Vitreous Ore ofCobatti Kobalt miilm, Schtaken-Kobatt. 3. This appears either in a loofe, powdery form, fometimes as fine as lamp black, either grey or bkckim, and called cobalt oehre, or in black indurated fcoriform maflesj called Schlaken Kobalt, or vitreous cobaltic ore : they are both commonly free from fulphur and arfenic, and wheti there are any, they are only mechanically mixed with this ore ; fome fmall proportion of copper and iron is alfo fomdtimes found in it ; it is frequently imbodied in ftones or fands of a black co- lour 5 talc, chalk and gypfum impregnated with it have been called by the fame name* and by fome Spiegel Cobalt ; it is alfo con- tained in fome green and blue earths as al- ready mentioned, p. 78, and 79* 4. Toanalyfe this ore let it be diflblved in the nitrous acid ; a plate of copper dipped in the folution will difcover and precipitate the filver, if any, and a plate of iron will dif- cover and precipitate copper, if the folutioa contains any ; but it mould fpeedily be with- drawn left the cobalt alfo ihould be precipi- tated ; Cobalt. 337 tated -r then the whole fhould be precipitated by a fixed alkali, and dephlogifticated by ab- ftra£tion of the nitrous acid and calcination ; if the calx be then digefted in diftilled vine- gar, the cobaltic part alone will be taken up, and may be precipitated by mild mineral al- kali. 1 60 gr. of this precipitate denote 100 of cobalt in its metallic ftate. SPECIES III. Mineralized by the Vitriolic or Arfenlcal Acids. Red Cobalt Ochre, Kobalt bluth, Fleurs de Cobalt. 5. This alfo is found either loofe and pure, or mixed with chalk or gypfum, or indurated and cryftalized in tetrahaedral cryftals, or in a ftaladtitical form ; it melts eafily, and then becomes blue ; it frequently invefts other co- baltic ores, and is found fometimes in ftonesf or fand. Mr. Bergman has fhewn that the arfenical acid, and not the calx of arfenic, enters into this combination, for cobalt is never red, but when united to an acid. 6. To analyfe this ore, Mr. Bergman ad- vifes to diflblve it in water, acidulated with fome acid (fuppofe the nitrous) and then to precipitate the cobaltic part with mild mi- neral alkali ; the liquor will contain cubic Z nitre 338 Elements of Mineralogy. nitre and Glauber's fait, if the vitriolic acid be the mineralizer, or arfenicated foda, if the arfenical acid exifts in the compound. SPECIES IV. Mineralized by Arfenic, with fear ce any Iron. Grey Cobalt Ore. Stahl derbon Kobalt, Glanty Cobalt. 7. Solid, heavy, compact, fometimes of a dull, and fometimes of a bright appearance, frequently cryftalized in a teflelar, fometimes In a dendritical form, and generally fo hard as to give fire with Heel. 8. It is analyfed by folution in aqua regia, or nitrous acid and evaporation to drynefs ; the reiiduum treated with the acetous acid will yield to it the cobaltic part ; the arfenic ihould at firft be precipitated by the addition pf water. 9. Or elfe this ore may firft be roafted to expell the arfenic, and then treated with ni- trous acid, the cobalt will be diflblved with very little of the iron, then by boiling the folution moft of the iron will be precipitated, and by adding a fixed alkali, the remainder of the iron will firft be precipitated yellowiih, and afterwards the cobalt reddifh. Mem. EerL Cobalt. 339 1 779. p. 1 6. So alfo the PruJJlan alkali will firft precipitate the iron blue, and afterwards the cobalt reddifh, (ibid.) or rather grey. SPECIES V. Mineralized by Sulphur and Arfemc 'with Iron. White arfenicated Cobalt Ore, Kobalt Glantz. 10. This bears a great refemblance to the Jaft, but is fofter, for it never ftrikes fire with fteel, and fometimes it is fo foft that it may be fcraped with a knife ; it rnoftly appears under fome polygon form > the moft ftiining forts of this, and of the former Species, have been called Cobalt Glantz. It is analyfable like the former Species ; the fulphur may be caught on the filter. SPECIES VI. Mineralized by a fmall Proportion of Sulphur 9 with a notable Proportion of Iron without any Arfemc. White unarfenicated Cobalt Ore. 11. It is fometimes found in large mafles, and fometimes in grains cryftalized, of a dull \yhite colour, and frequeutly bears the ap- Z 2 pearance 34-O Elements of Mineralogy. pearance of mifpickel ; it becomes black, and not red by calcination, which dtftinguifhes it from pyrites i it contains fo little fulphur, that none can be extracted from it ; when diflblved in aqua regia, its folution is yellow while cold, but greenifh when boiling, which viciffitude of colour is peculiar to marine co- balt ; it contains much more iron than it does cobalt. 1 2. In the dry way cobaltic ores, after free* ing them from their matrix by warning, and from fulphur and arfenic by roafting, are re- duced by melting them with three parts black flux in a lined and covered crucible, in a fmith's forge ; the beft ores contain from 60 to 80 per cent, of regulus, the worft under 25 per cent. Smalt is reducible in the fame manner, 13. To eflay the tinging power of cobaltic ores, the roafted ore is melted with three times its weight of pot-am, and five times its weight of pounded glafs or flint, putting in the pot- am firft, then the glafs or flint, and overall the ore. Schejf. 322. 14. If any bifmuth be contained in the cobalt ore, it will not mix with the regulus of cobalt, unlefs nickel alfo be contained in it, but will fimply adhere to it, and may be fe- parated Nickel 341 parated by the hammer, or by melting it, as it melts much eafier than cobalt ; when cobalt is by means of nickel united to bif* muth, the compound is called Speifs; fo alfo is a compound of cobalt, nickel, bifmuth, fulphur and arfenic* 15. In general, cobaltic ores are known by their property of affording fympathetic ink when digefted in aqua regia, after the bifmuth is precipitated by the addition of water. CHAP. XIV. Nickel I, Nickel is a reddifh white femi-metal of great hardnefs, fo that it can fcarce be filed, and of an equable texture I its fpecific gra- vity varies according to its purity from 7,421 to 9,000, the pureft being the heavieft ; when very pure it is in fome degree malleable, and always magnetic, and hence it is deemed to re- tain iron. The fufibility of the common re- gulus is nearly as that of copper : it calcines more difficultly than cobalt; its calx is green, and rifes in a tuberofe fungous form ; it is difficultly foli^ble in the vitriolic or marine acid, but eafily in the nitrous ; all thefe folu- tions are green, and volatil alkali turns them Z 3 blue. 342 Elements of Mineralogy. .blue, but iron difcovers no copper in them, as it does in every combination of copper^ fulphur, iron, arfenic and cobalt. Hence nickel muft be deemed a diftincl: femi-metal : befides, Mr. Bergman has ihewn that ful- phur, arfenic and cobalt may be perfectly fe- parated from it, though perhaps iron cannot ; but it feems to me very probable that nickel itfelf may be magnetic : the pureft regulus is ityuch more difficultly calcined or melted. SPECIES I. Native. 2. This is mentioned by Mr. Rinman to have been lately found in a mine of cobalt in Hejje ; it is very heavy, and of a liver colour, that is, dark red ; when pulverized and roaft- ed under a muffle, it forms green excrefcences, and fmokes, but its fmoke has no particular fmell, and no fublirnate, whether fulphureoits or arfenical, can be caught ; it is ibluble in 'acids, and the folution is green ; but a po- lifhed iron plate difcovers no copper. SPECIES II. Mineralized by the aerial Acid. Native Calx of Nickel. 3. It is found in the form of a green calx, mixed Nickel. 343 mixed with calx of iron, fcattered over the ore of kupfernickel ; alfo in fome greea clays. Cronft. §. 255. SPECIES III. Mineralized by the Vitriolic Acid. Vitriol of Nickel. 4. Already mentioned in the 2d Part* p. 195. SPECIES IV. Mineralized by Sulphur and Arfenic^ imth C if it be ex- pofed to the air, particularly in moift weather, it foon crumbles into a blackifh brown pow- der, 346 Elements of Mineralogy. der, which is fomething heavier than the regulus. It is foluble in acids, but moft readily in the nitrous, and its folutions are moftly colourlefs, but that in the nitrous is generally brownifh from a flight taint of iron, but there is always a fpurigy refiduum of the nature of plumbago, left undiflblved. Thefe folu- tions give a white precipitate with aerated alkalis, which precipitate when heated grows black. 3. The regulus is obtained by mixing the calx or ore of Manganefe with pitch, making it into a ball, and putting it into a crucible lined with powdered charcoal ~- of an inch thick on the fides, and ~ of an inch at bottom, then rilling the empty fpace with powdered charcoal, covering the crucible with another inverted and luted on, and expofing it to the ftrongeft heat of a forge for an hour or more, SPECIES I. Native. 4. This has not as yet been found, nor can it be expeded, (unlefs perhaps alloyed in native iron) as manganefe lofes the pro- portion of phlogifton neceflary to its me- tallic form, more readily than any other me- tallic fubftance. SPECIES Manganefe. 347 SPECIES II. Mineralized by the Aerial Acid. Native Calces of Manganefe* 5. The aerial acid is the only mineralizer of mahganefe in a dry ftate, yet known -, and according to the different degrees of phlogifti- cation of the manganefe, it forms with it calces of different colours and different properties, to underftand which it is iieceffary to remark, that when manganefe is as much phlogifti- cated as it can be, without being in a reguline ftate, it forms a •white calx, which contains a large portion of fixed air (about 40 per cent.) which enables it to retain phlogifton, as the compound of acid and calx, at- tracts phlogiflon more ftrongly than either does when flngle ; in proportion to its de- phlogiftication, and by union with other fub- Itances, its colour is either blue 9 greenly ellorw^ red) brown or black \ blue^ is that which it acquires from the proportion of phlogiflon, which it is enabled to retain by reafon of its union with fixed alkalis ; green arifes from a mixture of the blue with the yellow calx of iron -y yellow always arifes from the prevalence of the calx of iron ; red> from a flight phlogiftication of the calx of manga- nefe ; blacky from its thorough dephlogifti- cation. 348 Elements of Mineralogy. cation. Yet if the black calx be long roafted* it becomes green* which I think arifes from the expulfion of fixed air, which leaves its phlogifton with the manganefe, and thus produces a blue* which mixed with the yellow calx of iron, gives & green; broivn arifes from a mixture of the red and black calces of manganefe. Thefe obfervations I have ex- tra&ed from Ms. Scotch** incomparable differ- tation. 6. All thefe calces, of whatever colour they may be, communicate a garnet colour to glafs of borax, when treated with a blow pipe, for being melted into a round globule, the furrounding atmofphere dephlogifticates them fufficiently to make them affume this colour. 7. Hence we may diftinguifh 3 principal varieties of the native calx of manganefe, the white, the red, and the black. I. VARIETY. White Ore of Manganefe. 8. This contains but a very fmall proportion of iron 5 it has been found by Mr. Rinman both in fmall white cryftals, and in round mafles in the cavities of quartz and adhering to glanzblend, rather lefs hard than lime- ftone, Manganeje. 349 ftone, of a fparry texture, and fcarcely mag- netic even after roafting, foluble with effer- vefcence in nitrous acid, and affording a colourlefs folution, which folution, with mild alkalis, gave a white precipitate, and the pre- cipitate, when heated, presently grew blacks a fure criterion of manganefe. Mem. Stock, 9. Mr Lapeiroufe found this white ore in the form of a fpungy efflorefcence, vegetating on the furface of fome iron ores, particularly haematites. 10. It has been feen alfo by Mr. Rinman in the form of a calcareous fpar, of the colour of rofin^ and fomewhat {tuning, in fome places covered over with a footy powder, and in thin pieces femi-tranfparent at the edges, and not hard enough to ftrike fire with fteel ; nitrous acid diflblves it almoft intirely, with mild alkalis the folution gives a white precipitate, which blackens when heated. It confifts of manganefe imbodied in zeolyte, it melts perfe with the blow pipe into a whitifh grey porous flag, and with the addition of calcined borax gives a garnet coloured glafs. 11. Many of white fparry iron ores may alfo be claffed among the ores of manga- nefe, 350 Elements of Mineralogy. nefe, as they contain more of it than of iron. II. VARIETY. Red Ore of Manganefe* 12. It contains lefs fixed air, and is accom- panied with more iron than the former va- riety, and alfo with calcareous or ponderous earth and filex. It is found either loofe and iemi-indurated in a matrix of calcareous fpar, or talky fhiftus, or on hsemetites and other iron ores, or in heavy hard mafles of a lamellar, radiated, or equable texture, or cryftalized in pyramids, rhomboids, QV {hort bright brittle needles. 15. Roz. 6.9, III. VARIETY. Slack and Brown Ore of Mangctnefe. 13, I place thefe together, as they differ- but little ; they are found either cryftalized ia the fame form as the red ore, or in folid; mafles, fome of which have a metallic ap- pearance, others are dull, earthy, and mixed or embodied with quartz, or in a loofe earthy form ; their fpecific gravity is about 4,000 both, particularly the brown and the red arc foluble in fome meafure by digeftion in oil of vitriol, and the folution is at firft reddifh, but afterwards Manganefe. 35* afterwards becomes colourlefs, unlefs they contain a large proportion of iron. But the dephlogifticated nitrous acid does not a£t on them except fugar be added, and then this acid, as well as the concentrated vitriolic, operates a colourlefs folution, which with mild alkalis, gives a white precipitate of the fame nature as the firft variety ; they contain more iron and lefs fixed air than the former va- rieties. 14. Per Igor d Stone belongs to this variety, it is of a dark grey colour like bafaltes or trapp, may be fcraped with a knife, yet is difficultly broken ; when calcined it becomes of a red- difh brown colour and harder, but not mag- netic. Its fpecific gravity is confiderable, it does not mehperfe, but with borax it affords an amethyftine glafs ; nitrous acid fcarcely a£ts on it without the addition of fugar, this ftone feems alfo to contain argill, and fome portion of iron, 15. One of the moft remarkable ores of manganefe is that called black rwad j it is of a dark brown colour, partly in powder and partly indurated, and brittle. If half a pound of this be dried before a fire, and afterwards fuffered to cool for about an hour, and then two ounces of lintfeed oil be gradually poured on it, mixing them loofely like ba,rni with flour. 352 Elements of Mineralogy. flour, little clots will be formed, and in fome- thing more than half an hour the whole will gradually grow hot, and at laft burft into a flame, as I have feen feveral times at the houfe of Sir Jofefb Banks. The tempera- ture of the room where the experiment was made was about 50: the heat this ore was expofed to while drying might be about 130. 1 6. According to Mr. Wedgerwoo(T§ ana- lyfis 100 parts of black wad contain 43 of manganefe, 43 of iron, 4,5 of lead, and 5 of mica. 1 7. To analyfe the abovementioned ores, they fhould be firft roafted to dephlogifticate, the calx of manganefe, and iron if any, then treated with dephlogifticated nitrous acid to diflblve the earths ; the refiduum fhould then be treated with nitrous acid and fugar, by which means a colourlefs folution of manga- nefe will be obtained, which being precipi- tated by aerated mineral alkali, will give a precipitate 100 gr. of which are equivalent to 100 of regulusof manganefe. 1 8. Many fpecies of iron ore contain man- ganefe. To difcover it, let the iron be dif- folved in fome acid, and precipitated by the PruJJian alkali ; let the folution be poured off, and the precipitate digefted in pure water ; Manganefe. 353 water s the Pruffian manganefe will be dif- folved, and the PruJJian iron remain undif- folved. See alfo Chap. 5. N?4i and 53. Manganefe in Vegetables. 19. " Manganefe feems to be contained in the afhes of moft vegetables, and to it the blue or greenifh colour of calcined ve- getable alkali is owing. Thefe colours are generally attributed to the phlogifton " of the alkali ; but if fo, they fhould not *' be found in fixed nitre, as the nitrous acid '* fhould carry off during its decompofition u all the phlogifton ; yet this alkali is always " greenifh, fo that the colour feems to arife " from the afhes of the charcoal with which " the nitre was decompofed. If 3 parts of " the alkafi of tartar, i of fifted afhes, and " % of nitre be melted together, they form " a dark green mafs, which being diflblved " in water affords a beautiful green folution, " and this being filtered, on the addition of a " few drops of oil of vitriol, becomes red, " and after a few days a brown powder is *4 depofited, which has the properties of " manganefe." Scheele 56 Mem. Stock. 3C774> P* 189. The afhes of ferpyllum con- tain very little of it, thofe of trees contaia moft. Jbid. 1 80. A a CHAP, 354 Elements of Mineralogy^ CHAP. XVI. Siderite. 1. The firft diftindt mention I find made of this fubftance is in the Mineralogy of Mr. Monnet, p. 384, printed in 1779 * but the merit of difcovering its nature is undoubt- edly due to Mr. Meyer of Stetin, who, no$ contenting himfelf with vague generalities, developed its principal properties by a feries of ingenious and well connected experir ments publifhed among the Memoirs of the philofophical fociety of Berlin for the year 1781 and 1782 ; fome few of which he alfa mentioned in the Memoirs of the preceding year. Mr. Bergman, ignorant of what Mr. Meyer had done, arrived at the fame conclu- fions nearly at the fame time, as may be feen in the 3d volume of his works, and difcovered fome additional properties of thi$ new femi-metallic fubftance. From thefe fources I have extracted the following ac- count of it. 2. Siderite is principally found in iron or the firft fufion or caft iron, and in the ores of £oldfhort iron. The manner of its extraction has been already mentioned, Chap. 5. N? 46. A pound of caft iron fometimes affords; Siderite. 355 about 12 drachms of this calx, whofe natural colour is white, but it is generally tinged brown or yellow from a mixture of the calx of iron. Mr. Bergman purifies it by repeat- edly abftrading the nitrous acid over it, which dephlogifticates the iron, and leaves the calx of fiderite foluble in the mineral acids, but not in the acetous. 3. The folutions of it in the vitriolic and marine acids cryftalize, though very diffi- cultly ; it rather tends to form a jelly, parti- cularly if there be an excefs of acid ; the fo- lution in the nitrous is reddifh, and in the marine yellowilh ; all are flowly precipitable by water. 4. This calx is alfo in fome meafure fo- luble in water, but i part of it requires 1500 of boiling water for its folution. 5. Alkalis, both fixed and volatil, fome adtion on it, and acquire a brown tinge from it. 6. In the dry way it melts per fe on char- coal, and is not volatil ; it gives glafs a green colour, except it meets phlogifton, and thea the colour is brown. Y« It is reduced to a regulus by melting it A 3 % with 356 Elements of Mineralogy. ,v with half its weight of borax in a crucible lined to the thicknefs of ~ of an inch with a mixture of charcoal and a little clay, and expofing it to the fire of a fmith's forge for three quarters of an hour. 8. The regulus is of a fteel grey colour, fiot fo hard as cobalt, exceeding brittle, not magnetic in fmall pieces, though flightly fo when powdered. Its texture is granular ; its fpecific gravity about 6,710. 9. Its fufibility is nearly as that of cop- per, and it feems to contain fomething more phlogifton than iron does ; it is not volatil when heated. 10. It is very difficultly foluble in any acid, and requires the affiftance of heat ; arter ebullition for fome days ihe nitrous acid out of 5 grains diffolved only 4, aqua regia 4,2, dilute vitriolic acid 3,5, and the marine 3. Infufion of galls turns thefe folutions black ; the Prujfian alkali gives a dark blue precipi- tate, and common alkalis a white precipitate, 11. It precipitates gold, filver and copper very flowly from their folutions, and in their metallic form ; but lead from nitrous acid in the form o a calx; it does not precipitate rriercury from the nitrous agidi Molybdetifa 12. It is itfelf precipitated from the ni- trous acid in the form of a brown calx by zinc and iron. Copper feems to precipitate only a little dephlogifticated iron from it, to which a little of the white calx is united; lead alfo produces the fame effect. 13. It does not detonate with nitre, though it alkalizes it, and is dephlogifticated by it. 14. It does not unite with fulphur. 15. It fublimes with fal ammoniac, and takes a yellow colour. 1 6. It does not amalgamate with mercury, but when in fufion it unites with iron, cop- per, or cobalt, but not with any other me- tal, except perhaps nickel, which has not been tried $ it converts bar iron into the ftate of crude or caft iron, and when in a fmaller proportion renders it.cotdjhort. CHAP* XXIL Molybdena. Molybdena membranacea Cronft* 1 J4» Wafferbley of the Germans. I. It refembles plumbago, but its laminae are larger, brighter, and when thin flightly flexible ; it is of a lead colour, and does not A a 3 ftrike 358 Elements of Mineralogy. ftrike fire with fteel 5 its fpecific gravity fo 4,569. 2. In an open fire it is almoft intirely vo- latil and infufible. Microcofmic fait or borax fcarcely affecT: it, but it is adted upon witk much effervefcence by mineral alkali, and with it forms a reddifh mafs, which fmells of fulphur. 3. It is affeded by no acid, but the ni- trous and arfenical, both require the affiftance of heat 5 the latter is converted into orpi- ment. 4. Mr. Scbceltliz& found it to confift of an acid of a peculiar nature united to fulphur ; a fmall proportion of iron is commonly found in it ; but this feems merely fortuitous ; 100 parts of it contain about 45 of acid, and 55 of fulphur. 5. It is decompofed either by detonation with nitre, or by folution in nitrous acid : this latter method is the readieft : for this purpofe it is to be 5 times diftilled, each time with 4 times its weight of fpirit of nitre ; -a white calx at laft remains, which is the mo- Jybdenous acid. 6. This acid is foluble in 570 times its weight Weight of water in the temperature of 605 the folution reddens that of litmus, precipi- tates fulphur from the folution of liver of fulphur, &c. the fpecific gravity of the dry acid is 3,400. 3 Bergm. 127. 7. This acid is precipitkble from its fdlti- tion in water by the Prujfian alkali, and alfo by tindiure of galls the precipitate is reddifh brown. 8. If this acid be diftilled with three times its weight of fulphur, it re-produces molyb- dena, 9. The folution of this acid in water unites to fixed alkalis, and forms cryfta- li£able falts ; fo it does with calcareous earth* iriagnefia, and argill : thefe laft combinations are difficultly foluble ; it adls alfo on the bafe metals, and with them affumes a bluifh colour. 10. This folution precipitates filver, mer-i cury, or lead from the nitrous acid, and lead from the marine* but not mercuryi It alfo precipitates barytes from the nitrous and marine acids, but no other earth. Mo- lybdenous barofelenite is foluble in cold water, Aa4 ii. This 360 Elements of Mineralogy. u. This acid is itfelf foluble in the vi- triolic acid with the affiftance of heat, and the folution is blue when cold, though co- lourlefs while hot ; it is alfo foluble in the marine acid, but not in the nitrous. 12. Molybdenous tartar and ammoniac precipitate all metals from their folutions by a double affinity. Gold, fublimate corrofive, zinc and manganefe, are precipitated 1778. 14. This acid has been lately reduced by Mr. Hielm^ but the properties of the regu- lus thus obtained are not yet publifhed. CHAP. XVIII. Of the Tungftenic Acid. Though this acid, and the manner of ob- taining it have been already mentioned, p. 38, yet as it is of a metallic nature, a few of its diftinguifhing properties may properly be in- ferted here. i. Its folution in water reddens that of litmus ; Saturnite. 36 1 litmus; with alkalis it forms cryftalizable falts ; with barytes calcareous earth, and mag- nefia infoluble compounds. 2. This folution is precipitated white by the PruJJian alkali, and the precipitate is fo~ luble in water. 3. It precipitates the folutions of vitriols of iron, zinc, copper, and the nitrous folu- tions of filver, mercury and lead, and that of lead in marine acid; all thefe precipitates are white : the folution of tin in marine acid is precipitated blue, but the folutions of gold and fublimate corrofive are not altered by it. 4. The folutions of chalk or alum are not altered by it, but that of barytes in the acetous acid is precipitated, and the precipi- tate is infoluble. CHAP. XIX. Saturnite. The fubftance to which I ventured to give this name, is faid by Mr. Monnet, to be found in the lead mines of Pottl/aoven in Brittany, and is feparated from the lead ore during its torrefadion. According to him it relembles lead in its colour and fpecific gravity, Elements of Mineralogy. gravity, isfoluble in the fame acids, and witfl the fame phenomena ; but it is much mo're fufible, very brittle, eafily fcorified and vo- latilized, and refufes to mix with lead wheii ill fufiofu It were to be wiftied it was better examined. CHAP. XX, Reflexions on the nature of Cobalt ^ Nickel^ and Manganefe. I. The principal reafon why any fimple fubftances are reckoned fpecifically different from each other, is their manifefting pro- perties permanently different iri the fame cir- cumftances, and every fubftance muft be deemed fimple, until it can be refolved into* different principles, or formed out of them, fevery other indication is at beft a furmife grounded <3n mere poffibility, but deftitute of probability, and therefore inadmiffable iri any exact fcientifical fyftem i upon this foun- dation moft chymifts and mineralogifls have admitted the abovementioned fubftances to a diftincT: rank among femi-metals* Yet as fofne othef s deferVedly of great note, namely, Mr. Pabft, Mr. Monnet, and Romt de Lifle± have afferted, that all, or fome or other of thefe femi-met&ls, are either modifications of iron, or compounds of fome fort; I prefume it will not be amifs before I conclude this treatife* toi Hate Reflexions on Cobalt^ &c. ftate the reafons they have alledged* and juftify the opinion I have followed. Of Cobalt. 2. With regard to cobalt, fome have thought it to be nothing elfe but a compound of iron and arfenic, aflerting that fuch a compound would communicate a blue colour to glafs, but this pretenfion has been fully refuted by the experiments of Mr. Brandt. Mem. Sued* p. 46 and 47. and thofe of Mr. Monnet. Dijfa Des. Mett. p. 279. 3. Others have thought that the tinging quality is produced in cobalt, merely by its union with arfenic, becaufe it fometimes happens, that cobalt will not tinge, unlefs arfenic be added to it. But the true reafon of this phenomenon is, that cobalt will not tinge unlefs it is dephlogifticated, nor even, then unlefs it melts, and it fometimes hap- pens that cobalt is too much dephlogifticated, and then it will not melt in the ufual heat, without the addition of arfenic, which ferves as a flux to it ; for that arfenic is not other- wife efifential to its tinging property is evi- dent from this, that fomq cobalt ores, which tinge admirably well, are yet abfolutely free from arfenic, fuch as the vitreous ore, Sp. zd< It 364 Elements of Mineralogy. 4. It is true, that in feme circumftances glafs may be tinged blue by iron, as Mr. Gmelin has learnedly fhewn in the jth part of Mr. Cre/fs Chymical Journal ; but this iron is not transformed into cobalt ; for if that glafs be digefted in aqua regia, the folution will not form a fympathetic ink ; but, on the con- trary, will manifefl every property of iron $ •whereas glafs tinged blue by cobalt will,when digefted with aqua regia, afford fympathetic ink, and manifeft the other diftinctive cha- racters of cobalt. Nickel 5. Mr. Monnet thinks that cobalt and nickel are one and the fame metal, which when united to iron, exhibits the properties of, and is called cobalt, but when free from iron, is called nickel; fo that nickel is the fimple fubftance, and cobalt the compound. The folutions of cobalt he adds are red, merely on account of the iron, otherwife they would be green like thofe of nickel ; the blue tin- ging matter he fays is inherent in cobalt, but it cannot be developed without the addition of iron and arfenic. This opinion carries its own refutation with it, for common nickel always contains at leaft as much iron as cobalt does, and yet conftantly gives glafs a reddifh yellow colour, and if ever the addition of arfenic Reflexions on Cob alt ^ <&c. 36$ arfenic makes it give a blue tinge to glafs, it is becaufe it contains a portion of cobalt, which is not eafily dephlogifticated, but re- mains in a reguline ftate, and while it remains in this ftate, it can give no colour to glafs, but the addition of arfenic dephlogifticates this portion of cobalt, and thus enables it to unite to, and tinge glafs, and this is fo true, that the addition of nitre, which dephlogif- ticates ftill more powerfully than arfenic, produces the fame effed, as Mr. Bergman has {hewn in his elaborate differtation on Nickel, 2 Nov. A£l. Ups. p. 243. fo chat arfenic is no way neceflary ; and moreover it is abfo- lutely falfe, that the addition of iron and arfenic will ever give nickel the properties of cobalt, as Mr. Monnet himfelf muft well know. However, the reafons he alledges to prove the identity of thefe femi- metals are, 6. i°' That cobalt and nickel are foluble in the fame acids, and a£ted on by thefe acids in the fame manner, all the difference being that the folutions of cobalt are red, and thofe of nickel green ; a difference affuredly ve~y great, and which no addition of iron and arfe* nic to nickel will alter, as it fhould according to his fyftem ; for let him combine iron and arfenic with nickel as he pleafes, he will never make a fubftance whofe folution in acids will be red, as that of cobalt is; But further, if by 366 Elements of Mineralogf. by acids he means the mineral acids and the acetous, then he may as well fay that bif- muth is the fame fubftance as cobalt and nickel, for it is aclred upon by thefe acids in nearly the fame manner, but if he means the long tribe of other acids, the aflertion is not true, fmce the tartarous acid for inftance does not act on nickel, whereas it does on cobalt. 7. 2Iy* Becaufe though the ores of Nickel become green by calcination, and thofe of cobalt, blue, yet if the calcination of the nickel be continued, its calx will become brown j but I do not fee how this change to a reddifh brown, approximates nickel to cobalt, any more than the green colour does, for it is equally different from the blue or chocolate colour of cobalt, and it appears from Mr. Bergman's experiments, that the green colour arifes from a mixture of arfenic, for wheq nickel is thoroughly free from it, its calces are brown. 8. 3dly' Becaufe nickel long expofed to the air, contains a green ruft, as does cobalt But this appearance would as well indicate ,copper. 9. 4thly' Becaufe both nickel and cobalt unite with the fame metals. ]He probably forgo; Reflexions on Cobalt , &c. 367 forgot that cobalt and bifmuth will not unite, nor will cobalt and filver, or cobalt and lead, whereas nickel will unite to any of them when well purified from cobalt, and with bif- muthj even without fuch purification 10. 5tK1y- Becaufe according to Cronjled himfelf, nickel will give a blue colour to borax. But Mr. Bergman has {hewn, that when it is well purified from cobalt, it will give a hyacinthine, and not a blue tinge to borax. Mr. Monnet adds, that cobalt, melted with quartz and alkali, gives %greeni/h brown glafs in ibme circumftances, and quotes Brandt, but Brandt fays the colour was rtddtfh brown, and in effecl: this colour fhould be expefted from the fpecies of cobaltic ore he examined, which was loaded with iron, and from the manner in which the experiment was con- ducted, the cobalt being too much dephlo- gifticated. 1 1. Laftly, he obferves that the cobalt is al- ways magnetic ; but it is to be obferved, that this magnetifm conftantly decreafes in propor- tion as it is freed from iron, and yet the cobalt remains in full pofleffion of all its proper- ties, therefore its properties do not depend on the prefenceof iron, and if it were perfectly free from iron (a ftate of purity to which Mr. Monch fays he has reduced it, 3 Crdl. p, 164) it would not 368 Elements of Mineralogy. not be in the leaft magnetic j befides this ar- gument would fubvert Mr. Monnet's own opi- nion, for nickel is alfo always magnetic. 12,. Mr. Rome' de Li/le thinks that nickel confifts of iron, cobalt and copper intimately united :* although Mr. Bergman has demon- ftrated that this opinion is deftitute of any proof, either fynthetic or analytic ; for, in the firft place, he mixed thefe fubflances in various proportions, but could produce no- thing that refembled nickel ; and, in the id place, he fhewed that copper is very feldom mixed with it, and when it is, may eafily be feparated, and cobalt alfo may be fepa- rated though more difficultly. But Mr. Rome looks on the blue colour which volatil alkalis produce in the folutions of nickel, as an evident {ign of its containing copper. To make this proof of any weight, we muft aflfume this principle ; that two different me- tals cannot give the fame colour to the fame menftruuni) which is evidently falfe, for gold and platina give the fame colour to aqua regia, to fay nothing of the various me- tals, whofe folutions in nitrous acid are colourlefs. The only confequence ftriftly de- ducibie from the colour of a menftruum is purely negative; namely, that it does not * Chryftilographie, p, 91, finely Reflections on Cobalt, &c. 369 Jihgly contain any fubflance, which is known to communicate a different colour to that men- Jiruum in the fame circumjlances ; for there is fcarce any one property of any fubftance that may not be communicable to fome other fub- ftance, as it is only the aggregate of all their properties that fully diftinguifhes fubftances from each other. 13. He further adds, that nickel cannot be looked upon as a diftincT: femi-metal, be- caufe it cannot be thoroughly purified from iron. What ftrefs fhould be laid on this ar- gument, we fhall prefently confider in treat- ing of manganefe ; but in the mean time we may obferve that it is far from being clear that nickel can never be purified from iron ; for the only ground of this fufpicion is, that the pureft nickel is magnetic ; but this mud be deemed infufficient, unlefs it be taken for granted that magnetifm is a property inhe- rent in iron only, and incommunicable to all other pofiible metallic fubftanees, as we know it is to thofe that are already known ; a pofition which feems to me fully contra- di£ted in the cafe of nickel; for when it is pu-* rifiedas much as poffible from iron, it becomes more inftead of lefs magnetic, and even ac- quires what iron does not, the properties of a magnet. What hinders us then from al- lowing magnetifm, like the property of giv~ B b 370 Elements of Mineralogy. ing a blue colour to alkalis, to be common to thofe different metallic fubftances in which we find it ? Manganefe. According to Mr. Rome this ferni-metal is a mixture of iron, zinc and cobalt : that it contains iron is not denied ; but it is afferted, that befides iron it contains a peculiar femi- metal, whofe properties are independent of the prefence of iron, fince they are abfo- lutely different from thofe of iron, and every alloy of iron with any other known metallic fubftance, and are fo much the more appa- rent, as the portion of iron it contains is diminifhed. Neverthelefs, Mr. Rome objects that the regulus of manganefe can never be totally freed from iron, and that all the ex- periments hitherto made upon it being made on a mixed femi-metal, the properties dif- covered by thefe experiments ihould be deemed thofe of a mixed, and not thofe of a fimple fubftance. But the fallacy of this reafoning will readily appear, if it be confi- dered that, though until lately, platina could not be obtained perfectly free from iron ; yet the moft judicious chymifts in Europe, Lewis, Margraafi Schejfer, Macquer and Baiime, were of opinion that it was a peculiar diftincl: me- tallic fubftance; and at this day regulus of antimony and tin are never abfolutely free from tot Cobalt* from iron, yet no one dreams of attributing their peculiar properties to an alloy of iron, and any other metal ; and indeed if this manner of reafoning were of any weight, no properties could be attributed to any fimple fubftance ; for what fubftance can be procured abfolutely pure ? When was water rigoroufly pure ever found or procured, or gold of 24 carats ? Unlefs therefore we can produce by art a compound fimilar to that which we pre- fume to be a mixture, or Ihew fome good reafon why fuch a compound cannot be arti- ficially produced, or unlefs we can decom* pofe fuch fubftance, and thereby deftroy its peculiar properties, or at leaft alter them by the fubftra&ion of any one of its fuppofed conftituent parts, we muft look upon the fuppofition that fuch fubftance is effentially a compound^ as groundlefs relatively to the pre- fent ftate of our knowledge, on which alone, and not on mere poffibiiities, we can ra-» tionally found any aflertion. The word mo- dification has been ftrangely abufed on this occafion. Cobalt, nickel and manganefe, have been faid to be only modifications of iron ; but as long as it is not known wherein that modification confifls, this word prefents no idea whatfoever, and any other infignifi- cant word may as well be ufed. If it be laid that it denotes iron 'with the addition of fome unknown fubftance, then it would follow at B b 2 leaft, 372 Elements of Mineralogy. leaft, that by diminifhing the proportion of iron, the fpecific properties of the compound would be altered, which is not true with re- fpedt to thefe femi-metals, for the freer they are from iron, the more perfectly they ma* nifeft their peculiar properties ; fo that in every fenfe this afiertion is either falfe or un- intelligible. With refpeft to zinc and cobalt, there is not the leaft foundation for fufpe&ing, much lefs affirming, their exiftence in regulus of manganefe, as they are never found even in the ore of manganefe, except fortuitoufly ; but, on the contrary, this ore is moft fre- quently found without a • particle of either ; nor does the regulus fhew any property that approximates it more to them than to other metallic fubftances, but, on the contrary, many that belong to no other, nor to any compound of any other metallic fubftances. APPENDIX Geological Obfervations. 373 APPENDIX III. Geological Obfervations. Mountains: pLEVATIONS, confifting chiefly of day, •*•* fand or gravel, are called Hills 9 thofc that confift chiefly of ftone are by mine- ralogifts called Mountains. As they are the chief repofitories of minerals, and particu- larly of metallic ores, I fhall here relate the moft interefting obfervations relative to them that have occurred to me, or that have been made by others. Mountains may be confidered either with a view to their antiquity and origin, their height, or their ftrudure. Of the Antiquity and Origin of Mountains. In this point of view mountains are di- vided into primxvaly that is, of equal date with the formation of the globe, and fecon- dary, or alluvial; fome add even tertiary ; but this diftin&ion I think fuperfluous. Among the primaeval, thofe that confift of granite hold the firft place. The higheft mountains, and moft extenfive ridges in every B b 3 part 374 Elements of Mineralogy, part of the globe, are granitical. Thus the Alps and Pyrenees are the loftieft in Europe** and particularly fuch of them as confift of granite, the Altaifchan, Uralian and Cau~ cafus in Afia> and the Andes in America. From them the greateft rivers derive their origin. The higheft of them never contain metallic ores, but fome of the lower contain veins of copper or tin, as thofe of Saxony^ Silefta and Cornwall. The granitic ftones next the ore always abound in mica ; petre- faclions are never found in them. Many of the granite mountains of Afia and America form large plat-forms at about half their height, from which feveral lofty fpires arife. No fuch plat-forms have been obferved in the Alps or Pyrenees. 2* That the formation of thefe mountains preceded that of vegetables and animals is juflly inferred from their containing no or- ganic remains either in the form of petrifac- tion or impreffion, from their bulk, exten-r fion and connection, which feem too confi- ^erable to be afcribed to fubfequent caufes, and from their ufe and neceffity for the pro- duction of rivers, without which it is hard to fuppofe that the world bad exifted at any period fmce the creation of animals. Moft liaturaiifts are at preient agreed that granites Geological Qbfervations. 375 were formed by cryftallization. This opera- tion probably took place after the formation of the atmofphere, (which in the hiftory of the creation is called the firmament) and the gra- dual excavation of the bed of the ocean ; foon after which, it is faid, that by the command of God (that is, by virtue of the laws of na- ture which he eftablifhed) the dry land ap- peared ; for by means of the evaporation of part of the waters into the atmofphere, and the gradual retreat of the remainder, the va- rious fpecies of earths before diflblved ordif- fufed through this mighty mafs, were difpofed to coalefce, and among thefe \\itjiliceous muft have been the firft, as they are the leaft fo- iuble : but as they have an affinity to other earths with which they were mixed, fome of thefe muft alfo have united with them in various proportions, and thus have formed in diftinct mafles the felt fpar, fhoerl and mica, which compofe the granite. Calca- reous earth enters very fparingly into the compofition of this ftone ; but as it is found in Ihoerl, which is frequently a component part of granite, it follows that it muft be one of the primitive earths, and not entirely de- rived from marine exuviae as many ima- gine. Quartz can never be fuppofed to be a prod lift of fire, for in a very low heat it burfts, cracks, and lofes its tranfparency, and in thehigheft we can produce, it is infutible; Bb fo 376 Elements of Mineralogy. fothat in every eflential point it is totally un- like to glafs to which fome have compared it. As granite contains earths of every genus, we may conclude that all the fimple earths are coeval with the creation. This obfervation does not preclude further refearches into their compofition ; for though water undoubtedly dates from the creation, yet fome late expe- riments ihew it to be a compound : their fim- plicity may be only relative to the prefent ftate of our knowledge. Mountains, which confift of lime-ftone or marble of a granular or fcaly texture, and not difpofed in ftrata, feem alib to have preceded the creation of animals, for no organic traces are found in them. Alfo thofe that confift of ftones of the argillaceous genus, and of the 6th compound fpecies of the filiceous genus, feem to be primaeval, as they contain no or- ganic remains : thefe often confift of parallel ftrata of unequal thicknefs, and the lower are harder and lefs thick than the upper, whence the lower feem to have been firft formed, and the upper latter. They are the principal feat of metallic fubftances, whofe ores run acrofs the ftrata in all directions ; hence they are by the Germans called Gang geburge, and by the French Montagues ajihns. Coal is never foun4 Jn them. It Geological Obfervations. 377 It is little to be doubted, but that fubma- rine volcanos preceded not only the creation of animals, butalfo the feparation of dry land from the waters, the Mofaic expreffion, Let there be Light, feems to me to denote the confequences of thofe laws of nature to which vulcanos owe their origin. The fpecific gravity of the globe exceeds 3 or 4 times that of water, and confequently its proportion of earth is greater than that of water ; but at the creation the mafs of water as fpeci- fically lighter, lay for the mod part at the furface, until by the excavation of the bed of the ocean, and by evaporation, it made way for the appearance of dry land. Hence the interior regions of the globe, were never fo overwhelmed with water, but volcanos might be formed within them, as they are at this day under the lea. The flame of thefe fires being adapted to excite the fenfation of light, fufficiently authorifed Mofes to call it by that name, and the period during which it ex* ifted by that of Day^ in contradiftinction to the period of darknefs which preceded and fuc- ceeded it. Mr. Giraud de Soulavie has diftincHy proved the exiftence of thefe primaeval voU canos, in various parts of his Natural Hiftory of the South of France. Alluvial mountains are evidently of pofte- nor formation, as they contain petrefacliona and 378 Elements of Mineralogy. and other veftiges of organic fubftances, they are always ftratified. The principal granitic ridges are flanked by argillaceous, as thefe are by alluvial moun- tains. Of the height of Mountains. There is no circumftance relating to moun- tains, that excites the furprife, or interefts the curiofity of mankind to a greater degree than their height ; hence many methods have been devifed to determine it. The trigono- metrical is the moft antient, and in many cafes exadt, but it is often imperfect, and in fome cafes impracticable ; the barometrical alfo remained for a long time imperfeft, until the celebrated Mr. De Luc, with indefatiga- ble induftry, and uncommon fagacity, brought it to a degree of accuracy, " fcarce to be ex- pe£ted. Some improvements have lately been made in it by Sir George Shuckburgh^ and the calculation has been rendered ftill more fimple by Mr. Magellan. In this method the elevation of mountains is determined by the different heights of 2 columns of mercury, one at the top and the other at the bottom of the mountain, the de- gree ,v Geological Olfervations. 279 gree of heat of each being equal, or reduced to an equality, and the common temperature of the atmofphere being given. Two baro- meters are therefore ufed, and each has a thermometer annexed to it. The degree of heat to which both barometers are re- duced, is 55? of Fahrenheit, yet if either of the barometers be at 30 inches, and the ther- mometer attached^ to it at 55, no reduction need be made in that barometer j but if either barometer be at 30, and the thermometer at- tached to it below 55?, we muft add the expan- fion the mercury would have by the heat of 55?, or if it be above 55? we muft fubtrad the excefs of expanfion it gains by that heat.* Now every degree of Fahrenheit produces an expanfion, of, 00304 of the barometrical inch, when the baro- meter is at 30, therefore when the thermometer is at n degrees below or above 55? we muft add in the former, or fubtradt in the latter cafe, 0,00304 n to, or from the barometrical height. But if the mercury in the barometers ftand above or below 30 inches, then let the cor- redion be found as if the mercury were at 30, and let it be denoted by r, the correftion fought by x and the barometrical height b^ then ~= x. The thermometers fhould go alike, or if not, the difference fhould be ob- ferved and fubtrafted. * Thefra&ions to be added orfubtra&ed, are marked on 3 feparate fcale, called the fcale of corrcdtion. The 380 Elements of Mineralogy. The barometrical heights, of both barome- ters being thus corrected, the logarithm of the number of inches at which the mercury in the upper ftands, is to be fubftracted from the lo- garithm of that of the lower ; the difference between the 4 firft decimal figures on the left gives nearly the number of fathoms, as that of the two laft decimals does of the parts of a fathom between the upper and lower barome- ters, which being multiplied into 6, gives the number of feet and parts of a foot. I faid nearly r, for this height is not exact, except when the mean temperature of the atmofphere is 3??,24 of Fahrenheit. The mean temperature of the atmofphere is the arithmetical mean between the degrees, marked by two detached thermometers, one above, and the other below, both being held for about an hour in the ftiade. When this medium is 3^,24, the above method is juft, and requires no further cor- rection, but if the medium exceeds, or falls fliort of 3i?,24 that difference muft be found, fuppofe itz:^. The approximate height muft now be cor- rected by multiplying it in feet, into the fraction 0,00243, let the product—/*, then Geological Obf creations. jSr p d added to the approximate height, if the mean temperature be above 3i?,24, or fub- ftra&ed from that height, if the mean tem- perature be below 31,24 gives the true height. The following example will make the cal- culation more intelligible, the inftruments on the top of the mountain are denoted by A9 and thofe at the bottom by B. OBSERVATIONS. Barometer A - 25>T9 Inches. Its attached thermometer 46? Detached thermometer A 39,5 Barometer B at the fame time 29,4 Attached thermometer - 50 Detached ditto - - 45? CALCULATION. Here the lower barometer ftands below 30 inches, and its attached thermometer below 55? namely at 50. then 72 = 5 and ,00304x5 = ,01520 this would be the correction to be added if the barometer were at 30, but as it is at 29,4 then b_c_, 29,4 x, 01520^,44688 _ 0 g 3° " 3° 3° which 382 Elements of Mineralogy. •which is to be added to 20,4 29>^C \> ^ + ,0145 ^ 29,415 its cor reded height Again the upper barometer is at 25,19 in- ches, and its attached thermometer at 46 then 72 — 9. and £ — ,02736 and h £^25,19 x 02736 30" "^cT = ,02297— x and 25,i9 + o2297r:25,2i297 or in round numbers 25,213 as its corrected height. Now the logarithm of 29,415 is 1,468568, and the log. of 25,21$ is 1,401624, whofe 4685,68 difference is - 4016,2;). 669,44 The difference of the 4 firft figures on the left, gives the number of fathoms, and is therefore feparated by a comma from the laft, which gives the decimal parts of a fathom, and 669,44, x 6 — 4016,664 feet, this is the ap- proximate height. The mean temperature is next to be found. The detached thermometer A was at 39,51 and the detached thermometer B at 45, now then 39>5 Geological Obfervatlons 383 39>5-H5~84>5 and— ^ = 42,25, which is 2 therefore the mean temperature of the atmof- phere ; the difference between this and 31*24 =: 11,01 —d. The fraction ,00243 *s now to ^ plied into 4016,664, the produdt is 9,7604 which multiplied into d— 107,462, and as the mean temperature is above 31524. pd is to be added to the approximate height then 4016,66 + 107,4611:4124,12 feet, the true corrected height. Some of the moft remarkable mountains, whofe heights have been taken with tolerable accuracy are, IN AMERICA. Englifli feet above the level of the fea. Chimbora^o - 20575,8 or 3, 89 miles. El Cora9on - n 15783 The town of Quito - 9243 IN AFRICA. Teneriffe - - 11022 De Borda 1 3 Raz. Pico Ruivo in Madeira - - - 5141 PblL tranf. 1765. IN 384 Elements of Miner alogjf. IN EUROPE. Mont Blanc, highefl of the Alps 15672 Sir G. Shuckburgk Pbll.tr. 1777. Vefuviusin 1776 3938 Sauflure, jflEtna ... 10954 Canigou, one of the Pyrenees 9214 St. Bartelemi in pays de Foix 7565 Mont d'Or in Auvergne - - 6696 PuydeDome ... £221 Hecla .... <;ooo Von Troil. The height of the Afiatic mountains has never been accurately determined. Mr. Berg- man remarks, that the fphericity of the earth is no more altered by the height of the higheft mountain, than that of a globe of 2 feet in diameter, would be by an elevation of the fize of a grain of fand. The line of congelation in fummer, under the Equator, is at the height of 15400 feet; at the entrance of the temperate zone, 13428 ; on Tenenffey in latitude 28, at about 1000; in Auvergne, in latitude 45, at 6740 nearly; with us, in latitude 52, it is probably at 5740. The greateft height hitherto afcended, is 157^3 feet; in Peru9 vegetation ceafes at the height of 14697 feet, and on the Alps^ at 9585, Mr. SauJJure found the air lefs pure at 3 834 feet 5 Mr. UArcct obferved, that on the Geological Obfervations. 385 the Pic de midi (one of the Pyrenees, lower than Conlgou) fait of tartar remained dry for an hour and a half, though it immediately moiftened at the bottom of the mountain. The vapor of marine acid was alfo inviiible on the fummit. The eledlric and magnetic powers were as ftrong as on the plain. 8 Roz. 4°3- Of the Structure of Mountains. Mountains confidered as to their flru&ure, are divided into intire> Jiratijiedy and confu- fed. Intire mountains are formed of huge maf- fes of ftone, without any regular fiffure, and moftly homogenous ; they confift chiefly of granite, fomedmes of gneifs, fhiftus, flagftone, fandftone, limeftone, gypfum, porphyry, ferpentine, or trapp. Some in Sweden and Norway confift of iron. Stratified mountains are thofe whofe mafs i^ regularly divided by joints or fiffures ; thefe ftrata are confidered in relation to the angle which their fiflures make with the ho- rizon and meridian, with refpecT: to the former they are called horizontal, rifmg, or dipping. With regard to the latter, they are faid to run to this or that point fo many degrees 5 G c they 386 Elements of Mineralogy. they are moft commonly parallel to eachother, and rife or fall with the mountain. The ftrata of which mountains confift, are either homogeneous or heterogeneous. Homogenous ftratified mountains confift chiefly of ftones of the argillaceous genus, as fhifti, hornftones, flagftones, or of the fif- file compound fpecies of the filiceous genus, as gneifs, and metallic rock, or of both, the one behind the other. Sometimes of pri- maeval limeftone, that is, limeftone of a gra- nular or fcaly texture, in which no animal veftiges appear. This limeftone repofes on the argillaceous or filiceous ftrata; fometimes the argillaceous are covered with mattes of granite, and fometimes with lava. Thefe mountains, as already obferved, are the chief feat of metallic ores, particularly thofe of gneifs, metallic rock, and hornftone. When they are covered with limeftone, the ore is generally between the limeftone and the argillaceous ftones. Thefe ores run in veins and not in ftrata. The calcareous rarely contain any ore, when they do, it is either iron, copper, lead, or Mercury. Petrefac- tions Geological Obfervations. 387 lions are found upon, but not in thefe moun- tains. Heterogenous,orcompoundftratified moun- tains *, confift of alternate ftrata of various fpecies of ftones, earths or fands either of the calcareous or argillaceous genus, or both, or metallic ores, and fometimes lava, as toad- ftone, &c. The lime-ftone is always of the laminar, and not of the granular or fcaly kind, and when it contains any ore, this is placed between its laminae ; it is very feldom that ftones of the filiceous genus form any ftratum in thefe mountains, except lavas ; but the ftrata are frequently interrupted by filiceous mafles ; fuch as jafper, porphyry, granite, &c. thefe may be called flops f. Coal, bitumen, petrifications and organic impreffions, are found in thefe mountains ; alfo falts, calamine, gold in the fandy ftrata, iron in intire ftrata or neftways, copper in the ftrata, lead ore, fingly or mixed with copper, (it fometimes {hoots through the ftrata in fmall veins,) cobalt ore in the flops, pyrites every where ; it fometimes confti- tutes whole ftrata ; the matrixes of thefe ores are chiefly of the calcareous or barytic genera, rarely quartz, and never mica. * Flotxgelurge. f Klancken, kamme, RucJien Week- f*1. I am not acquainted with the correfpondcnt EngKJb technical terms, C c 2 There 388 Elements of Mineralogy. There are other mountains analogous to thefe, which yet cannot properly be called ftratified, as they confift only of three im- jnenfe mafles ; the loweft granite, the mid- dle of the argillaceous genus, and the upper- moft-of lime-ftone. When they are metalli- ferous, as they generally are, the metallic ores are found in the argillaceous part, or between it and the calcareous ; thefe ores form veins or bellies, and not ftrata ; thefe may be called triplicate mountains. Confufed mountains; that is, of a confufed or promifcuous ftrudure, confift of ftones of all forts heaped together without any order ; their interfaces are filled with fand, clay and mica ; they fcarce ever contain any ore. Of Volcanos. Volcanos, or burning mountains, are pe- culiar to no climate, and have been obferved in every quarter of the globe : they have no neceflary or regular connection with other mountains, but they feem to have fome with the fea, for they are generally placed in its; neighbourhood. It is true that antient ex- tinguifhed volcanos have lately been difco- vereci in the inland parts of moft countries 5 but this is one of the many proofs that the fea at feme remote period covered thofe coun- tries. Geological Obfervatwns. 389 tries. Sub-marine volcanos have often been obfervecl even in our own times. Thefe mountains are of all heights, fome fo low as 450 feet, as that in Tanna *^ but they generally form lofty fpires, internally fhaped like an inverted cone placed on abroader baiis. This cone is called the crater of the volcano, as through it the lava generally paries, thc-ugh fometimes it burfts from the fides, and even from the bottom of the moun- tain ; fometimes the crater falls in and is ef- faced; fometimes in extinguifhed volcanos it is filled with water, and forms thofe lakes that are obferved on the fummit of fome mountains. Both the crater and bafis of many volcanic mountains confift of lava either intire or de- compofed, nearly as low as the level of the fea, but they finally reft either upon granite, as the volcanos of Peru, or on fhiftus, as the extinguilhed volcanos of Heffe and Bohemia, or on lime-ftone, as thofe of Sllefia, the Vi- centine Alps^ and Vefauius. The decompofed and undecompofed lavas form irregular firata that are never parallel to each other. No ore is found in thefe mountains, except iron, of which lava contains from 20 to 25 per cent. * Fojler, 143. C c 3 and 39© Elements of Mineralogy. and fome detached fragments of copper, antimonial and arfenical ores. If we confider the immenfe quantity of matter thrown up at different periods by vol- canic mountains, without leffening their ap- parent bulk *, we muft conclude the feat of thefe fires to be feveral miles, perhaps him* dreds of miles, below the level of the fea ; and as iron makes from T to J of all thefe ejections, we may infer that the interior parts of the earth confift chiefly of this rcietal, its ores, or ftones that contain it, whofe greater or lefler dephlogiftication in different parts may be the caufe of the variation of mag- netic direction. The origin of thefe fires is not eafily ac- counted for. It is well known that mar- tial pyrites, being moiflened, will acquire heat j but that this heat fhould burn: into actual flame, the concourfe of open air is ab- folutely requifite ; however, if we fuppofe the heated pyrites to have been in contact with black wad and petrol, we may fappofe the flame to arife, as we fee it produced by art from the deficcation of that fubftance, and its mixture with the mineral oil, Thaj; ore when heated affords dephlogifticated air, * Mr. Gerhard computes that Vefwlus has ejected from the year 70 to the year 1783, 309658161 cubic feet. 2 Mi" ntral. Gefcb, §.87. Of Geological Obfervattons. 391 of which a very fmall quantity is fufficient to produce flame : this flame once produced, may be fupported by dephlogifticated air from other ores, which Dr. Prie/lly has {hewn to afford it, and the phlogifton may be fupplied by pyrites, bituminous fhiftus, bitumen and coal ; marl, fhiftus, horn-ftone, ftioerl, with a further addition of iron from the pyrites, are the true fources of the melted matter or lava. The explolion and eruption of this melted matter proceeds, in all probability, from the accefs of a large quantity of water, which either enters through fome crack in the bottom of the fea, or from fources in the earth ; if the mafs of water fo admitted be fufficiently great, it will extinguifh the fub- terraneous fire; if not, it will fuddenly be converted into vapour, whofe elaftic force is known to be feveral thoufand times greater than that of gunpowder ; if the fuperincum- bent weight be too great, it may caufe earth- quakes, but will propel the melted matter lat- terally towards the mouth of the volcano, where, meeting with lead refiftance, it will expel it, together with all the unmelted ftony maffes it meets in its paflage. It is eafy to conceive that before the denfe melted matter is ejected, the dilated air of the vol- cano will firft be forced out, and carry with it the afhes and loofer ftones adhering to the fides and crater of the volcano, as has been C c 4 obferved, Elements of Mineralogy. obferved, and elegantly defcribed by our mo- dern Pliny Sir William Hamilton. The fubftances ejected by volcanos are, phlogifticated, fixed, and inflammable air, water, afhes, pumiceftones, ftones that have undergone no fufion, and lava. The water proceeds partly from that con- tained in the volcano, partly from the con- denfed vapors, and partly perhaps from the intimate union of the phlogifton and dephlo- gifticated air ; an union which fome late ex- periments fhew to be productive of water in certain circumftances. Part of the afhes is plentifully moiftened with this water, and forms tufa traafs> &c. Stones of all forts and fizes, even of 10 feet in diameter, are projected by volcanos* and fometimes to great diftances : hence probably thofe folitary maflfes of granite, which are fometimes met with in lime-ftone countries. Lavas, in their paflfage through the vol- •cano and its caverns, and during their flow- ing, ,neceirarily involve various forts of ftone, which are not therefore products of fire, though found in lava ; fuch as quartz, fpar, Ihoerl, &c. and thus various porphyries and pudding- Geological Obfervatlons. 393 pudding-ftones are found, which have lava for their ground. Bafaltes, and in many inftances fhoerl, feem to me to ow6 their origin both to fire and water : they feem to have been atfirft a lava, but this lava, while in a liquid ftate being im- merfed in water, was fo diffufed or diffolved in it with the affiftance of heat, as to cryfta- lize when cold, or coalefce into regular forms. That bafaltes is not the refult of mere fufion appears by a comparifon of its form with its texture ; its form, it being cryftalized, fhould be the effect of a thin fufion, but in thatcaie its texture fhould be glafly; whereas it is merely earthy and devoid of cavities. Hence we may underftand how it comes to pafs that lava perfectly vitrified, and even water, are fometimes found inclofed in bafaltes. Mon. Mineral. 511. Von Troi/, 285. The immenfe mafles of lava ejeded by volcanos, prefenting but a relatively fmali furface to the atmofphere, are many years in cooling, and many hundreds of years are re- quired for their decompofition ; this decom- pofition is quicker or flower as they have been more or lefs perfectly melted. According to the obfervations of Sir William Hamilton, the lava of Vefuvius forms one or two feet of mould in 1000 years; this bed of mould being 394 Elements of Mineralogy. being afterwards covered with frefh lava, aricf this, after mouldering by that of ftill latter eruptions, affords fome ground for calculating the age of the volcano at leaft within certain limits. The beds of lava are deepeft and narrowefl in the proximity of the crater, and broader and fhallower as theyare morediftant, unlefs fome valley intervenes ; pumiceftone and ames lie ftill more diftant. From thefe obfer- vations extinguifhed volcanos are traced. Many excellent inveftigations of this fort may be feen in Mr. Sou/aviis hiftory o£ the fouth of France. Bafaltic mountains (common in Sweden) feem to owe their origin to lub-inarine vol- canos. Purifications. The moft remarkable obfervations relative to petrifactions are, ift- That thofe of fhells are found on or near the furface of the earth ; thofe of fifh deeper, and thofe of wood deepeft, Shells mjpecie are found in immenfe quantities at confiderable depths. 2%. That thofe organic fubftances that re- fift Geological Obfervations. 39$ fift putrefaction moft are frequently found petrified ; fuch as {hells and the harder fpe- cies of woods : on the contrary, thofe that are apteft to putrefy are rarely found petrified, as fifh, and the fofter parts of animals, &c. ^aiy. That they are moft commonly found in ftrata of marl, chalk, lime-ftone or clay, feldom in fand-ftone, ftill more rarely in gypfum, but never in gneifs, granite, ba- faltes or fhoerl j but they fometimes occur among pyrites, and ores of iron, copper and filver, and almoft always confift of that fpe- cies of earth, ftone, or other mineral that furrounds them, fometimes of filex, agate, or carnelian, 4thjy- That they are found in climates where their originals could not have exifted, thofe found in flate or clay are comprefled and flattened. Of Metallic Ores. Iron ore is the only one that forms intire mountains , all other ores form but an in- confiderable part of the mountain in which they are found, Ores either run parallel to the ftony ftrata, or 396 Elements of Mineralogy. or run acrofs them in all directions ; thefe* laft are called 'veins. The courfe of veins, with relation to the meridian, is called their direction, and with relation to the horizon is called their inclina- tion. Their direction, in the language of mi- ners, is denoted by hours; the horizontal circle being divided into twice 12 hours, 12 from fouth to north, and 1 2 frorn north to fouth : eaft and weft directions are therefore denoted by 6 o'clock. Inconfiderable veins that diverge from the principal are called Jlifs ; confiderable mafles of ore that have no great length are called bellies or Jlock-ivorks ; fo are alfo accumulated veins or thick bodies of ore formed by the junction of feveral veins. The ftones which fill the cavities that form the veins are called the matrix (gang) of the ore ; the rocks that lie over the veins are called the roof- thofe that lie under them the Jloor^ and by fome the hading ; the matrix is almoft always a finer fpecies of ftone than the furrounding rocks, though of the fame genus ; even the rocks themfelves are finer grained as they approach the vein. There I Geological Obfervatlons. 397 There is no matrix peculiarly appropriated to any metal; it has only been remarked, that tin is generally found among ftones of the filiceous genus, and lead very frequently among thofe of the calcareous. There is no certain fign from which the exiftence of an ore in any mountain may be inferred, except the veftiges of it in the beds of torrents or mineral waters, anc) the ftruc- ture of the mountain itfelf, of which enough has been already faid. Of Hof Springs. Mr. Tifflngton has remarked, that waters flowing through a blue marl filled with no- dules of pyrites are warm; Mr. Guettard has alfo obferved, that all the hot mineral fprings of France flow from ihiftus : hence there is no occafion to derive their heat from fubterraneous volcano. TABLE 398 Elements of TABLE I. The Quantity of Metal in a Regullne State af- forded by 100 Grains of different Metallic Calces^ and to which confequently they are rejpeffiively equivalent. 100 Grains ----- Grains. Brown calx of iron afford of regulus - - - from 79 to 89 grs, Red ditto - - - from 71,4 to 78 Brown calx of copper from 84 to 86,5 Minium ----- 89 Calx of tin - - - - 96 Precipitate per fe - - 92 Flowers of zinc - - 85,5 Calx of bifmuth 98 Grey calx of antimony 96 White calx of manganefe 54 Hence the quantity of calx, which loo parts of any of thefe metals would afford, is eafily found; thus loogr. of lead would af- ford 113 of minium for -^89. 100 : : 100 TABLE *« ( 399 ) W *t ^^ "S s 3-1 I -I s^s .§ 8 5 ^ -5 o C3 ^ fg •« LH O • ^o o o ~ • II OS p"S fH ,J o ^s ,0 .-£ « ^ .t; «S o o C5 •V I • O £ JS 2 "S « s w ^^! ,2 G als^'e o Il 11 vo O O O^ G • "§• cq a T3 rt . -I *-S 15 r: It s MOO 8 "8 fis tS II g •^ o 8 bO O en iy • »^ rrj *-^5 ^•^ «« o Hlfl Qj OS £ -~ "2 o e':§ «Sel W rt C tr* , rt ° ta < Ss w o S.S 3 Q - -8 g *-• 4J» O CJ £3 JH •§ 'H T3 £ a o S 85T5 c "<3 w N OO O "8 . .a 'o ** rt "5 CO ^ la •^ o C rs >> €0 -0 S "2 § rs » ff« !j c* o II c rt ^ •s-S' B o !i o 8 2 T « a .^-S 05 ^ '_£ M O '£-« 5** s^ u ^ CO 03 2 I £.- ^ Irs-F s. ^J §s r=J H-i S o bJO M f> 5 QJ ti i o u< 3 . — i3/2§ Serpentine - 45 23 18 12 3 Talc Mufcovy - - - ?o — 4? 5 Talc Venetian - - - a larger portion"of : irgil i and fmaller of magnefia. Note, The magnefia and calcareous eartha are in a mild flate in all the above ilones. * At a medium and 30 fixed air. f And z of talc. t At a medium. J! At a medium. § And 6 barytes. Argillaceous Genus, Silex. Argiil Calcareous Magnefia. Iron. V ^rater. Pure clay dry - - 63 37* — — — Argillaceous marl dry 46 27 25 "f MM* — — Fuller's earth - 53 18 5 3 4 *7i Pouzzolana - " 57 20 6 ,o — Tripoli - - - - 90 7 — — . —*— 3 — Pure mica - - - 38 28 20 j 4 II — Martial mica - 34,5 25>5 18 52 — Roof llate or (hiilus 46 26 4 mild 8 mild J 4 ~. Flagft. or argill. ihifl* 36 5° 4 — Horn-ftone - - 37 22 2 16 -3 Killas 60 25 «*••• 9 6 — Toadftone - - -63 7 • i •••• — i 6 — Zeolyte - 60 20 8 — I2§ Pitch -done - - 65 16 . • 1 HI !.•• mtmm .—- — 5 14 "II Gronftcn Horn-ftone and mica, or horn- ftone and-Aiorl. SteHfteii Mica, quartz and argill. Binda Horn-ftone, mica, fliorl, quartz, and pyrites. Grovvan Argill, mica and quartz. * At aniedium wnen peifectly dry, 63 hi^-eous. f Mild at a medium, J And marine acid ftt a medium. }| White calx of iron, § At a medium, ^ And air. ( 4°9 ) Vitreous copper ore — 10 or 1 2 fulphur, and 90 of copper. j4zureore—20 to 30 iron, from 40 to 60 of copper, the remainder fulphur. Telloiv copper ore — pyrites, fulphur, and from 4 to 30 parts of copper* Grey copper ore — arfenic, pyrites, from 35 to 60 copper, and a little filver. Bkndofe copper ore — pyrites, pfeudo galena, from 1 8 to 30 copper. Shijlofe copper ore — fchiftus, fulphur, from 6 to 10 of copper. 100 Parts. Iron. Steel ore — from 60 to 80 iron. Black eifen rahm — 74 plumbago, 26 iron. Sparry iron ore — 38 calcareous earth, 2 ganefe, and 38 iron. Flos ferri — 65 calcareous earth, and 35 calx of iron. Magnetic fand of Virginia — about 50 of iron. Hematites — from 40 to 80 of iron. Grey iron ore — fiderite, and. from 40 to 66 of iron. Highland argillaceous ore — from 30 to 66 of iron. Ditto fwampy — fiderite, and 36 of iron* Siliceous ore — 25 to 30 of iron. 100 ( 4*0 ) too Parts. Tin. Black tin ore — 80 tin, fome iron. Red ditto — more of iron than of tin. Sulphurated tin — 40 per cent, fulphur, a little copper, the remainder tin. 100 Parts. Lead. White lead ore — a little iron, argill or calca- reous earth, 80 to go of tin. Red ditto — more iron, argill, 80 or 90 of lead. Green ditto — ftill more iron, feldom copper. Bluifh ditto — a little copper. Vitriol of ditto — about 70 of lead. Galena — from 15 to 25 of fulphur, from 0,0 1 to 1,5 or 2 of filver, from 60 to 85 of lead, befides quartz and iron. Antimonial lead ore — antimony, from 0,08 to 0,16 filver, and from 40 to 50 of lead. Pyritous lead ore • • • pyrites, 18 to 20 of lead. Red leadfpar — realgar, a little filver, and 43 of lead. 100 ( 4" ) loo Parts. Mercury. Native calx of mercury — 9 fixed air, and 91 mercury. Vitriol and marine falts of dittQ — About 70 mercury. Cinnabar-~>'2o Sulphur, and 80 mercury. Pyritous ore of mercury — Cobalt, arfenic, pyrites, I of mercury. joo Parts. Zinc. Vitreous Ore, Zinc, Spar — 28 Aerial acid, 6 iwater, \ iron, and 65 calx of zinc. Tutanego — Iron, argill, and from 60 to 90 of zinc. Ca/amine-*-lron, clay, rarely calcareous earth or lead, 30 to 84 calx of ditto. Zeolytic ore* — Quartz, water, and about 36 calx of zinc, Blende, pfedogahna blue — 8 iron, 4 copper, 26 fulphur, 4 water, 6 filex, and 52 zinc. Ditto black — I Arfenic, 9 iron, 6 lead, 29 fulphur, 6 water, 4 filex, and 45 zinc. Ditto red — 5 Iron, 1 7 fulphur, 5 water, c argill, 24. quartz, and 44 zinc. DittO) phofphoric — 5 Iron, 20 fulphur, 4 fparry acid, 6 water, i filex, and 64 zinc. Ditto grey — Galena, petrol, fulphur, 24 zinc. too ( 4" ) ioo Parts Regulus of Antimony. Antimony — 26 Sulphur, and 74 regulus. Arfenicated ditto — The fame as the plumofe filver ore. zoo Parts Regulus of Arfenlc. Orpiment — 10 Sulphur, and 90 arfenic. Realgar — 16 Sulphur, and 84 arfenic. ioo Parts. Manganefe. sparry iron ore — 50 Calcareous earth, 22 iron, and 28 calx of manganefe. ioo Parts. Molybdena — 45 Acid, 55 fulphur, FINIS, LOAN DEPT