CRYSTALLOGRAPHY. 



470 



Crystalline 

 Forms. 



Calamine. 



PlATB 



CCXXVI. 



Fig. 23. 



Pyramids 

 having a 

 squire 

 base. 



Meilite. 



Zircon. 



Figs. 24, 

 25. 



Harmo- 

 tome. 

 Fig. 26. 



Oxide of 

 till. 



Molybdate 

 i>i lead. 



Figs. 27, 

 28. 



in Cornwall, has been described by Bournon in the 

 Philosophical Transactions. Hauy has reduced all his 

 species under the common laws of decrement. 



12. Calamine. This mineral occurs but rarely crys- 

 tallised. Hauy, however, in his Mineralogie, has de- 

 scribed three varieties of form. The most common is 

 that represented in Fig. 23. 



III. Pyramids having a Square Base. 



To this primitive form belong seven species of mine- 

 rals; namely, 



1. Meilite, or Honeysione. This singular mineral oc- 

 curs crystallized in the primitive form, and in dodeca- 

 hedrons differing about one degree in the inclination 

 of the faces from the common rhomboidal dodecahe- 

 dron. 



2. Zircon, including the Hyacinth. It occurs in the 

 primitive form, also in various other forms. The most 

 usual are represented in Figs. 2-1. and 25. The sym- 

 bol for the first is 'E 1 P; for the second D P. The 



s P l 



I P 

 first is the most common form of hyacinth, the second 

 of the jargon of Ceylon. 



3. Harmotome, cross stone, or staurolite. The most 

 common variety of the crystals of this species is repre- 

 sented in Fig. 26. Its symbol 'E 1 P. 



o P 



4. Oxide of tin, tinstone. Hauy at first supposed the 



Srimitive form of this species to be the cube, but he 

 as more recently found it to be an octahedron. The 

 crystals of this species are numerous. By far the most 

 accurate description of them has been drawn up by 

 Mr Philips, and will be probably published in the se- 

 cond volume of the Transactions of the Geological Sor 

 ciety of London. 



5 Molybdate of lead. The crystals of this species 



have most commonly the forms represented in Figs. 27. 



i 

 and 28. The symbol for the first is D A ; for the se- 



h jr 



cond D 'E 1 A. 

 h I I 



6. Anatose or octnhedrile. This species consists of Crystalline 

 pure oxide of titanium ; yet its crystalline form is es- Forms. 



sentially distinct from the titanite. Besides the primi- , "" 



../ c „ ., * Anatose. 



tive, it occurs m various forms ; one ot the most com- 

 mon of which is represented in Fig. 29- The symbol ^ t , ATr _ 

 for it is P A. The crystals of this species are always p CX ^ VI ' 



P r 

 very small. 



7. Tungstate of lime. Hauy at first supposed that Tungstate 

 the primitive form of this species was the cube, but he °' linie. 

 afterwards found it to be the octahedron. It occurs 

 usually crystallized in octahedrons. 



IV. Pyramids having a Rhomb for their Base. Pyramid* 



having a 

 There are four species of minerals that belong to this rhomb for 

 primitive form, namely, r baie ' 



1. Carbonate of soda. The primitive form of this Carbonate 

 species is represented in Fig. 30. The angle which the °, f !, °^ a - 

 edge D makes with D' is 120°, and the inclination of & 30 * 

 the face P to P' is 7% °. The most common crystalline 



form of this salt is exhibited in Fig. 31. Its symbol is Fig. 3!. 

 PA. 



P o 



2. Sulphur. Very splendid crystals of this mineral Sulphun 

 have been brought from Spainand Sicily. It occurs in 



the primitive form, often' lengthened edgewise, and 

 sometimes the points of the pyramids are truncated. 

 We give no figures, because there never can be any, 

 difficulty in distinguishing the species.. 



3. Blue carbonate of copper, hydrate of copper. This Blue ear- 

 species occurs crystallized, but the crystals are so small bonate of 

 that it is scarce possible to determine their form with c °pper. 

 accuracy. Hauy has followed Rome de Lisle, who ob- 

 tained his crystals- by evaporating an ammoniacal solu- 

 tion of copper. 



4. Splwne and titane silico-calcaire of 'Hauy. This Sphene. 

 mineral occurs frequently, in rhomboids, with their al- 

 ternate angles truncated We want still a good de- 

 scription of the crystalline forms which it assumes. 

 Hauy will doubtless supply the deficiency when his 



new edition makes its appearance, (c) 



CUB 

 Cuba. CUBA, one of the largest of the West India Islands, 



■— y-"™'' stretches from east to west from the seventy-fourth to 

 the eighty-fifth degree of west longitude, and lies be- 

 tween the parallels of 19° 56' and 2'3° 18' of north la- 

 titude. Its greatest length, from Cape Maize on the 

 east to Cape St Antonio on the west, is 764 British 

 miles ; its greatest breadth at Cape de Cruz is 1 33 

 miles, and its least breadth 74 miles. It is about 62 

 miles to the west of St Domingo, 168 miles to the east 

 of Yucatan, 9^> to the north of Jamaica, and 130 to 

 the south of Florida. 



A long chain of mountains extends from east to 

 west along the whole length of the island, and di- 

 vides it into two parts. About 158 rivers and brooks 

 have their origin in this range, and carry down with 

 the detritus of the mountains a very fine gold, which 

 affords reason to believe that there are mines of this 

 metal in the interior. At the foot of these mountains 

 are large tracts of meadow ground, called Savannas, 

 which feed an immense number of cattle, both wild 

 and tame, the skins of which form one of the prin- 



ce U B 



cipal articles of the commerce of the island. The 

 skins are reckoned superior to any of those from ■.other s 

 parts of the West Indies, and are known in Europe by 

 the name of the skins of the Havannah, the town from 

 which they are exported. About 10,000 or 12,000 

 skins were annually sent from the island. 



The mountains abound in large timber, particularly 

 the cedar and acajou, caobas, oaks, granadillos, guaya- 

 canes, and ebony trees. The fertility of the soil is 

 great. The most delicate herbs and fruits are in full 

 blossom the whole year round, the fields are, constantly 

 covered with flowers, and the trees never lose their fo- 

 liage. Two crops are often produced annually from 

 some of the seeds, one of the crops coming to maturity 

 in the middle of winter The temperature of the is- 

 land is very warm and dry, and, owing to the refresh- 

 ing gales from the north and east, it is more mild than 

 that of the island of St Domingo. A great deal of rain 

 falls in the months of July and August ; but the other 

 months of the year are hot and dry. 



The principal productions of Cuba are sugar, coffee. 



Cuba. 



