IVORY. 



397 



l"y- pearance, and sometimes i encircled by so dark a 

 W ""Y"^ shade as greatly to injure the ivory. Tusks are mo=t 



esteemed which have feast hollow. 



Wsssiss Nothing can be more diversified than the dimensions 

 c tuAj gf ^jjg 1,^3 c |- t he elephant, and hence the dealers in 

 ivory distinguish them by names according to their 

 size. If weighing under 1 i or 20 pounds, they are 

 called crtreUtt, or, as the workmen say, scrii-elu, many 

 not exceeding a foot in length. None brought tro.n 

 the south-west coait of India exceed four feet it is said ; 

 but some of an extraordinary bulk are obtained in other 

 countries. In Roman history, we read of tusks ten 

 feet long ; and Mr. I'ennant s|>eaks of others equally 

 laigr, brought from the coast of Mozambique, in mo- 

 dern times. Tusks of eight or nine fict long are repeated- 

 ly mentioned ; and Hartenfeh, in his work on elephants, 

 instances one, of the wonderful length of 1 1 feet, in the 

 possession of a merchant in Venice. Very Urge tusks are 

 six, seven, or even nine inches thick, according to 

 Camper, who observes, that one about seven feet nine 

 inches long, nine inches thick, and weighing 208 

 pound*, belonged .to a merchant of Amsterdam. No 

 general conclusions regarding the weight are deducible 

 from the size. Tusks have been known to weigh 325 

 or 550 pounds. Some fossil tusks are also very ponde- 

 rous. One is described by Brevne, in the l'/iilosoj>fii- 

 cat Transaction}, 136 inches 5 fines long on the exte- 

 rior of the curve, whose circumference was 18 inches 

 "i lines at the root on clearing the socket, and which 



pounds. The largest, found on the 

 i of the Frozen Ocean during the Russian voyage 

 of discovery m 1787, were eight feet seven inches 

 lone following the volute, but only four feet and an 

 inch in ft straight line, very nearly 18 inches in cir- 

 cumference at the thickest part towards the root, and 

 weighing 115 pounds avoirdupois. Cuvier supposes, 

 that tiuks grow during the whole life of the elephant ; 

 and a* the extremity is always wearing off', the real 

 length is uncertain. But that learned author, on in- 

 spect sections, would have been sensible, that 

 ipioy want very little if any portion of the extremity, 

 although others be greatly blunted, or even broken o\cr 

 by some uncommon degree of violence. The 1. 

 tusks are said to be brought from Africa, and the 

 straightett from Asu ; and it is thought that those least 

 curved afford the best ivory. Nevertheless, we do not 

 (iHisidii these points as established ; and we are disposed 

 to doubt whether the quality of the ivory is indicated by 

 any external appearances, or whether much depend' 

 ence can be placed on any except very simple rules for 

 judging of it. 



1 and elastic, anil ii considerably more 

 transparent than white paper of equal thickness. The 

 outside is covered by a cortical substance, softer than 

 the rest ; brown or almost black externally, by which 

 also the cavity is lined. In general, it is nearly a 

 line thick, though sometimes scarcely perceptible on 

 approaching the tip. The ivory, in both caves, is coar- 

 ser; that i, the grain is larger and more perceptible 

 in the vicinity of the bark, softer, and, as we think, 

 more readily discolours on exposure to the air. It pro- 

 gressively becomes finer on receding from the exttn..d 

 cortical part ; and where there is no sensible bark on 

 the cavity, it seems to have attained the greatest 

 fectioo. Hardness ami whiteness are the only pt 

 ties desirable. But that is most prized which exhibit.* 

 a kind of diaphanous appearance when first cut asun- 

 der. The outside is always to be rejected, as also por- 

 tions near the nerve. 



The structure of elephants' ivory exhibits no import- 



ant differences. The disk of a transverse section always Itory. 

 presents a number of granulated line* in a zigzag di- """^Y""" 

 rection, which gradually become more delicate on ap- Texture> 

 proaching the interior, until they totally disappear from 

 the naked eye. M. Cuvier affirms, that this character, 

 common to all elephants' ivory, and depending im- 

 mediately on the pores of the pulpy nucleus of the 

 task, is not to be found in the tusks of any other ani- 

 mal. \Ve shall remark, in general, that the texture of 

 the ivory of different animals which we have exa- 

 mined, is very different. On reducing a transverse 

 section of a portion of very fine ivory to the thickness 

 of 1 00th part of an inch, we found innumerable con- 

 centric circles surrounding the cavity, disposed, as it 

 were, in bands of irregular breadth. At this thick- 

 ness, the ivory required a high polish to expose them ; 

 and they were indistinct without the aid of a magnifi- 

 er. But on reducing a piece greatly thinner, and 

 through which common printing would easily be read 

 when laid upon a page, they were readily seen with 

 the naked eye. Very minute lozenges were observed 

 to be formed by intersecting curves, and many stria; or 

 radiations, in which were minute square masses more 

 opaque. Instead of the conical intersection, the ;vaiu 

 near the bark' exhibited waved white lines amon^ the 

 browner part. A longitudinal section of ivory pre- 

 sents somewhat of a lamcllated aspect ; of uniform co- 

 lour in a fine tusk, but sometimes more distinctly 

 marked, and with yellowish edges in others. The tex- 

 ture resembles that of wood ; and, on examining a thin 

 plate, it will be found to be extmurly similar to the gene- 

 ral appearance of ash, consisting of alternate irregular 

 darker and lighter streak*. By reducing it to extreme 

 thinnes*, they become infinitely less f.erceptible, and 

 the ivory assumes a bluish transparency. It may be 

 thence understood, that the tusk is formed of innume- 

 rable concentric circles, so intimately united as to con- 

 stitute one solid and coiiM-trnt whole. \Vheii in a 

 state of decomposition by lying lout; in the earth, it se- 

 parates into thin concentric conical plates ; and some- 

 times, though very rarely, we have observed a portion 

 separate in this manner from recent ivory. Mr. Corse 

 Scott is of opinion, that the age of an elephant might 

 be deduced from the number of layers ; but it is not 

 certain that they grow regularly year by year, and 

 besides, they appear different in a large and thick 

 section than in one which is very thin The iuu 

 ture of this annular formation is particularly conspi- 

 cuous in what is called the tooth of the whale, which is 

 probably a real tooth. The cortical part is very thick, 

 and much whiter than the red, and it is of about equal 

 hardness. That of a section, of an inch and a half in 

 diameter we found to be an eighth of an inch thick, of 

 a homogeneous surface to the naked eye, but seen to 

 consist of the thinnest layers on the application of a 

 magnifier. Instead of the granulated apja-arancc and in- 

 tersecting curves of elephants' ivory, the whole is dis- 

 posed in numerous concentric rings, exactly resembling 

 those which surround the pith of a tree, proceeding 

 from the centre to the circumference. They are of un- 

 equal breadth, and seem arranged in grains, with an 

 intermediate transparent ring. Very fine and delicate 

 radiations also proceed from the centre to the cir- 

 cumference, and a play of light is produced, which 

 gives the surface somewhat the appearance of the cat's 

 eye. Observations on plates of ivory are greatly facili- 

 tated by the application of oil or water, which produce 

 such transparency as to expose the internal and also 

 the superficial structure. 



The teeth of the sea horse, morse, or trichecut rot* 



