210 



MINERALOGY 



MINERAL WATERS 



to constitute natural groups by h.mng regard to 

 both. 



minerals Inking of great use, ami others 

 :\ valuoil lur their beamy, have received much 

 ;i:;fiiiinii from the earliest ages, lint the ancient 

 naturalist* describe few minerals. The first attempt 

 at scientific mineralogy wjis hy George Agricola in 

 the Kith century. The .systems of the Swedes 

 Wallerius anil Cronstedt, in the later half of the 

 IKtli century, were the lir>t worthy of the name. 

 That of Werni-r followi-d, ami was extensively 

 adopted. Tim discoveries of Hauy in crystallo- 

 graphy, and the progress of chemistry, gave miner- 

 alogy a now character ; and then sprung up two 

 schools of mineralogists, one resting chielly on 



nal characters, and the other on chemical 

 composition. 



The chemical classification of minerals is rendered 

 ditlicult by the endless variety of comliination and 

 proportion in the elements of which they are com 

 p'-"d, the presence of substances not essential to 

 the mineral, and yet more or less affecting it 

 charucters, ami the frei|iient inipossihility of deter 

 mining what is to I* deemed essential and what 

 accidental. Chemical purity is almost never found 

 in nature. Even the purest diamond, when Imrneil, 

 leaves some traces of ash ; ami the various colours 

 of diamond, quart/, and other minerals are due to 

 the presence of siihstanc.es which are often in so 

 small quantity as not to ailed their crystalline 

 forms or other physical properties. Again, some 

 minerals of identical chemical composition ditler 

 in their crystallisation, so that an arrangement 

 founded upon it would separate them too widely. 

 There are also many minerals which are often 

 found in an uncrystaflised state, and others which 

 are always so. In the arrangement of minerals 

 into natural groups, their chemical com|x>siiion, 

 although not alone to lie regarded, is of the first 

 importance, so that the place of a new mineral in 

 tin- system can never be determined without 

 analysis; and in determining the nature of a 

 mineral chemical !'-:-. such as the application 

 of acids, are continually resorted to. It is also 

 necessary to know its specilic gravity, and how it 

 Is acted upon both by a moderate heat and by the 

 blowpipe. An examination of the crystalline forms, 

 with measurement of the angles of the crystals, is 

 often sufficient to distinguish minerals which ban- 

 otherwise much resemblance. The cleavage of er\ s 

 tals is also important a readiness to split in planes 

 parallel to certain of their faces only, liy which the 

 jiriiiiitiif f-irm of the crystal may l>e ascertained. 

 Minerals not crystallised exhibit important vat ii 

 of xlr lift lire, as luiiiiiiiitfil, Jiln-nnx, i/nniiitiir. \<\ 

 Certain peculiarities of /,,,-m arc also trci|uenlly 

 characteristic of uncrystallised minerals. as innnul 

 lurji, liotryuiiliil, \c. Minerals exhibit, when 

 broken, very different kinds of fnu-turf., as at*, 



r>, /, nt,l!,.tj,/in/,-i, <//, 



and frnnx/iitrt iii-fi are more or less characteristic of 

 different kind- and iii'ii/inln- properties 



demand attention ; and very important characters 

 are derived from lu*tn-. which in some minerals is 

 metallic, in otheis ..mi niftnllif, in otheis fu-nr/i/, 

 mtrcoiu, &c. Colour is not generally of much im- 

 |M>rtanc<>, but in some minerals it is very character- 

 istic. The colour of the powder formed when a 

 mineral is scratched often differs from that of the 

 Bolid muss. This is tin- at rail: of the mineral, and 

 i frequently very characteristic. Hardness and 

 .ire very important, and arc of all various 



-. r,i:/,i.,...h/ and other peculiarities to l>e 

 aoccrtained by the touch are very characteristic of 

 some minerals, and peculiarities of taste, and smell 

 Iwlong to others. 



Mineralogy bus very important relations with 

 geology, which cannot be studied without regard 



to the mineral constituents of rocks. The miners! 

 composition of soils greatly affect* vegetation and 

 agriculture. The economical uses of minerals are 

 also very Important and various. It is enough 

 merely to allude to salt, sulphur, liorax, alum, 

 graphite, cryolite, native metals, metallic ores, ixc. 

 Naphtha, petroleum, bitumen, asphalt. \c. are of 

 well-known utility : and a high value has a!v 

 been attached to gems and other ornamental 

 stones. There are special handliooks by llaucrniaii, 

 Hana, Woliler, lirush, and ErnL See GEOLO^, 

 CKYSTALLOGRArilY. 



Mineral Oil. Sec KAKU, NAPHTHA, PAR- 



AKKIS, 1'KTKOI.Kr.M. 



Mineral Tallow, or HATCIIETTIXE, a remark- 

 able substance found in several places in liritaiir, 

 Cermany, Siberia, &C., soft anil flexible, yellowish 

 white, yellow, or greenish yellow, resembling wax 

 or tallow, often (laky like spermaceti, imidoroii-, 

 melting at 115 to 170 F., and composed of about 

 8(i ]>er cent, carlmn and 14 per cent, hydrogen. The 

 mineral is closely related to, if it be not identical 

 with, o/okerite or native parallin. Like other 

 hydrooubOBS, such as naphtha, petroleum, asphalt, 

 ix-c. , Hatchet line appears to have resulted from the 

 chemical alteration of organic matter. 



Mineral Waters, spring waters which possess 



qualities in relation to the animal body different 

 from those of ordinary water, have been used as 

 remedial agents from a very early period. The 

 oldest Greek physician* hail great faith in their 

 curative power, and the temples erected to .Iv-cu- 

 lapius were usually in close proximity to mineral 

 springs ; the warm baths of Calirrhoe, near the 

 I>ead Sea, are mentioned by .loseplius as having 

 l>een tried by Herod in his sickness. \Ve are 

 indebted to the liomans for the discovery not only 

 of the mineral thermic springs in Italy, but. of 

 some of the most important in other parts of 

 Europe, amongst which may be named Aix-la- 

 Chapelle, Ituden-Ituden, liath, Spa in lielgium, 

 and many others; and 1'liny (\<ttitr<il Jlixtory) 

 mentions a very large number of mineral sprini'- 

 in almost all parts of Knrope (see P. VI II, Ilvniin- 

 ! \ I II V !. The theraiieutic action of mineral w. 

 or spas depends diieliy upon their chemical composi- 

 tion and their temperature, though other circum- 

 stances, as situation, elevation, climate, geological 

 formation, mean temperatiiie, ,Vc., have an impml- 

 ant iM'aring upon the sncci>s of tlie treatment. 



The Iwst time for undergoing a course of mineral 

 waters is. in the majority of cases, the months of 

 June, July, August, and September. There 

 however, exceptions depending upon climate ; for 

 example, at (iastein, celebrated for its thermal 

 springs, the weather is changeable and stormy in 

 June and July, hut pleasant in May. August, and 

 Septemlicr. V.arly rising is usually advisable dur- 

 ing a course of mineral waters, and, as a general 

 nile, the water should lie drunk before breakfast, 

 at intervals of about a quarter of an hour between 

 each tumbler, moderate exercise being taken in 

 the intervals. In many cases bathing is of even 

 greater importance as a remedial agent than drink- 

 ing. Maths are generally taken between breakfast 

 and dinner, and should never be taken soon after 

 a full meal. The time during which the patient 

 should remain in the bath varies \ery much at 

 different spas, and the directions of the local 

 physician should IK' strictly attended to on this 

 jMiint. As a general rule, the treatment should 

 not be protracted beyond the space of six weeks 

 or two months, but on this point the patient must 

 be solely guided by the physician resident at the 

 spa. Indulgence? in the pleasures of the table, and 

 excesses of any kind, fiecpicntly counteract the 

 salutary elfects'of the waters, while perfect mental 



