CRYSTALS CUBA. 



555 



surface, deduced an ingenious and useful theory of 

 the forms of these bodies. This theory being founded 

 oil abstruse mathematical principles, we cannot here 

 enter into its minute details ; but we shall lay down 

 the leading results. The carbonate of lime is founded 

 in crystals of six sides or hexahedrons. Now, if we 

 take one of these crystals, and endeavour to divide 

 it parallel to the edges by introducing a sharp knife 

 at the base, we will find tliat only three will divide at 

 each end, the three at the one base being alternate 

 to the three at the other. There will then remain a 

 solid bounded by six trapeziums, each having a 

 lustre which shows that it is one of the natural joints 

 of the crystal. Continuing the divisions parallel to the 

 first sections, it will be found, that the bases will con- 

 tinually diminish until they disappear altogether, and 

 also that the altitudes of the lateral sides diminish 

 until we arrive at a twelve-sided solid (dodecahedron) 

 bounded by pentagons ; but by continuing the sections, 

 we arrive at faces of a triangular form, and continu- 

 ing still farther, we arrive at an obtuse rhomboid, 

 which is called the nucleus or primitive form of the 

 crystal. The nucleus of one crystal may and often 

 does differ from that of another in form, but the nucleus 

 of the same crystallized substance is always the same. 

 The nucleus or primitive form of carbonate of lime is 

 an obtuse rhomboid ; all the other forms which pre- 

 ceded it in the division are called secondary. This 

 mechanical division may, however, be carried still 

 farther by separations, parallel to the bounding sur- 

 faces, and sometimes division is practicable in other 

 directions until we arrive at last at the integrant mole- 

 cule, which is no longer divisible excepting by the ac- 

 tion of chemical agents. The form of the integrant 

 molecule of a crystal is always one of these three, 

 the tetrahedron, the triangular prism or the parallelo- 

 piped, these figures being the simplest class to which 

 they belong. The integrant molecules or particles 

 of crystals have been supposed by Dr Wollaston, to 

 be composed of spherical atoms, which formed differ- 

 ently shaped molecules, according to their number. 

 Three would form a triangular pyramid, four a cube, 

 and with two added, one at each end, an acute 

 rhomboid, &c., &c. ; which figures may be imitated 

 with leaden bullets. These atoms, being attracted, 

 form the particles that cohere from the nucleus, 

 which again is surrounded by laminae, formed by the 

 particles, and these lamina? decrease in magni- 

 tude by the subtraction of molecules, as they advance 

 from the nucleus to the surface of the crystal. The 

 angles of crystals are measured by an instrument called 

 the gonometer (q. v.). Me shall conclude this article 

 by referring for further particulars to Dr Ure's Che- 

 mical Dictionary. We subjoin an outline of a few of 

 the crystals. 



CUBA; the largest and most westerly of the 

 Antilles. Its configuration, extent, geographical 

 position, great number of ports, fertility, and climate, 

 contribute to render it one of the most interesting 

 countries of America. Its length, from cape St 

 Antonio to point Maisi, in a direction from W. S. W. 

 to E. N. E., and then from W. N. W. to E. S. E., 

 is 257 leagues, and its greatest width, in the direc- 

 tion north to south, is 38 leagues. The learned 

 geographer don Felipe Bausa calculated, in June, 

 1825, that the surface of Cuba contained 3615 

 square marine leagues (20 to a degree). Cuba is 

 situated between Ion. 73 56' and 85 W., and 

 between lat. 19 48' 30" and 23 12' 45" N. It 

 lies fourteen leagues west from cape Nicolas, in the 

 island of St Domingo, thirty-four south from point 

 Morant, in Jamaica, twenty-seven east from cape 

 Catoche, and thirty-seven south from cape Florida. 

 The gulf of Mexico, which is very nearly of a 

 circular form, of more than 250 leagues in circum- 

 ference, is closed by the island of Cuba, with the 

 exception of two narrow passages, the one to the 

 south, between cape Catoche and cape St Antonio, 

 and the other to the north, between Bahia Honda 

 and the Florida shoals. Along the coast of Cuba 

 are many keys and small islands, which are in- 

 cluded in the same government with the large 

 island. The navigation of the coast is very unsafe 

 on account of the rocks and shoals which encompass 

 it almost without interruption, and often extend 

 from two to three miles into the sea. The broken 

 outline of this vast extent of coast, however, affords 

 more than fifty ports and anchoring places, which are 

 equally safe and easy of access. The most remark- 

 able, in a commercial point of view, are those of 

 Havannah, Matanzas, Nuevitas, Jibara, and Bara- 

 coa, on the north ; St Jago, Manzanillo, Trinidad, 

 Jagua, and Batabano, on the south side of the island. 

 There is another port between Manzanillo and 

 Trinidad, called Santa Cruz, which, in February, 

 1829, was declared a free port, and which, undoubt- 

 edly, will be much frequented, furnishing great 

 facilities for trading with Puerto Principe (the 

 second city in Cuba in point of population), being 

 the only good harbour in its vicinity on the south 

 side of the island, and distant from it but twenty 

 leagues. The harbours of Bahia, Honda, Nipe, 

 Naranjo, and Guautanamo, also deserve to be men- 

 tioned, as they are very spacious, and have plenty 

 of water for such large vessels as may be in want of 

 a safe port. A ridge of mountains traverses the 

 whole of the island, from the ear, to the west, 

 dividing it into two parts. At the foot of these, the 

 country opens into extensive savannas. A consider- 

 able number of small streams from these heights 

 water the island on both sides. These streams 

 abound in fish of different kinds, and are said to 

 bring down considerable quantities of gold. There 

 are likewise many salt ponds, which furnish 

 abundance of fish and game ; also several springs of 

 mineral water, which nave proved very useful for 

 the cure of many diseases. The most remarkable 

 are those of St Diego, forty leagues west of Havan- 

 nah ; those of Madruga, fourteen leagues S.W. of the 

 said city ; those of the town of Guanabacoa ; and 

 those of Camugiro, one and a half league from 

 Puerto Principe. Those of St Diego are the only 

 ones which have been analyzed. They consist of 

 two wells (Tigre and Templado), and according to 

 the analysis of sennor Esteves, a pound of the water 

 contains 0-46 grains of sulphureted hydrogen gas., 

 10-5 of sulphate of lime, 1-0 of hydrochlorate 01 

 magnesia, and one grain of carbonate of magnesia. 

 They are particularly useful in cases of scrofula, 

 cutaneous diseases, &c. 



