NATURAL HISTORY. 



Plate 

 262. Fig. 27. 



16. 



17- 



18. 

 19. 



28. 



22, 



23- 

 25. 

 29. 



31- 



Regular Oftohedron 

 Truncation on the angles 

 on the edges 

 Bevelment on all the edges 

 30. on all the lateral edges 



on the angles 

 Acumination, the acuminating planes 



at each angle let on the lateral 

 planes 

 26. on the lateral edges 



24. on the lateral planes 



on the lateral angles 

 on the alternating lateral planes 

 double eight-fided pyramid, 

 four planes at each extremity 

 fet on the alternate lateral 

 edges 

 double fix-fided pyramid, with 

 the planes joined obliquely, 

 or metaftatic cryftal 



The primitive Forms of Cryjlals are, 



Fig. I. The Cube 

 2. Rhomb 



7, 8. Reftangular Table 

 27. Octohedron 

 Tetrahedron 

 Hexagonal Prifm 

 Rhomboidal Dodecahedron 

 Dodecahedron with triangular faces 



13 



5 



12 



14 



Fig. 



13- 



29. 



I. 



The integrant Molecules are, 



The Tetrahedron 



Trihedron 



Cube 



Jnjlruments employed in the Study of Cryjlallography and 

 Mineralogy. 



261. Fig. 91. Nicholfon's inftrument for determining the 

 weight or fpecific gravity of folid bodies 

 92. B. An inftrument for determining the eleftri- 

 city of minerals 



92. A. An inftrument for determining the eleftri- 



city of the tourmaline 



93. Goniometer for meafuring the angles of 



cryftals 

 ( Vide Mineralogy, Appendix, Vol. XXXIX. 

 — Vide alfo article Crystal, Vol. X. ; and 

 Crystallization, Supplemental Vol.) 



Appendix to Geology, Mineralogy, Mining, Sfc. 



263. Plate Mineralogy, Mining. 



Fig. I — 10. Mining — conftruftion of the ftiaft or 

 paflage leading to mines, mode of 

 defcent, manner of clofing or rtopping 

 them up, &c. 



253. Reprefented on Plate IV. Geology. 



Fig. 6. Plan of a Coal Mine, and mode of ventilating 



250. Mining Lamps, Plate I. Geology. 



Fig. 5, 6. Sir Humphrey Davy's Wire Gauze 



Plate 



250. 



F'g- 2. 3' 



4- 



Safety Lamp, as made by Mr. New- 

 man, Lille Street, Leicefter Square 

 {See Wire Gauze) 

 Dr. Clanny's Safety Lamps 



Steam Safety Lamp 



19. 

 26. 

 29. 

 3"- 



46. 



53 



54' 

 56, 



51 

 58 



«*« By attending to the above claflification, the whole of 

 thofe Plates of Natural Hiftory, which the pro- 

 prietors have allotted to this Cyclopadia, may be 

 readily reduced to numerical order, and be by 

 that means, it is prefumed, more eafily diftinguifhed 

 when required for reference than by the original 

 plan, in which the plates of each feftion were 

 lettered feparately from the reft. They now fol- 

 low each other, not only in numerical order 

 throughout their whole extent, but alfo in the 

 order of the Linnaan Syftem, as nearly as the 

 number of plates appropriated to the refpeftive 

 Sciences would conveniently allow. The mifcel- 

 laneous nature of fome few plates, which it has 

 been lately thought defirable by the proprietors 

 to introduce, renders it impoflible to place them 

 ftriftly in the order of fyftem. 



ERRATA 



ON THF. 



PLATES OF NATURAL HISTORY. 



Some few errors having been committed by the 

 writing engravers in lettering the names upon the 

 plates of Natural Hiftory, which it will be very 

 defirable to correft, the reader is requefted to 

 obferve, that wherever the names upon the plates 

 are found at variance with thofe inferted in this 

 printed index, the preference is to be invariably 

 given to the latter ; and that the names upon the 

 plates may be correfted by a reference to this index. 

 The following errors occur to us in palling over the 

 plates for the purpofe of compofing the prefent 

 claflification. 



Quadrupeds. 



For Brafiliar Weefel, read Brafilian Weefel 

 Taguan Squirrel, r. Taquan S. 

 Mol'pymaius, r. Mos pygmxus 

 Antilope Gr'immea, r. Ant. Grimmia 



Birds. 



For Ramphaftos Aracani, read R. Aracari 

 G. Crotophagi, r. G. Crotophaga 

 Merops Novas Zelandia?, r. Novs Selandisc 

 Certhia coccina, r. C. coccinea 

 Certhia csrulia. r. C. caerulea 

 Anas Olot, r. A. Olor 

 Anas Creca, r. A. Crecca 

 Manderine Drake, ;•. Mandarine Dr. 

 Genus Aptenodytes, r. G. Aptenodyta 

 Gen. Diomedia, r. Diomedea 

 D. Chiororynchos, r. Chlororhynchos 



