270 



HARDWICKE'S SCIENCE-GOSSIP. 



When, however, it becomes voracious, it does not 

 wait for its victims to appear, but turns over the 

 earth with its blunted muzzle and seeks them below. 

 I have lately noticed that the two condyles, or gills, 

 situated at the side of the vertebral chasm, appear 

 to be losing their identity. It is possible, that in 

 course of time they may disappear altogether, as the 

 economy of nature does not allow for the maintenance 

 of a disused organ. At present it is breathing solely 

 by the lungs, so that the gills are not called into play, 

 and are therefore not required by the creature. 1 

 notice, too, that its colour is changi ng from dark to 

 light grey, and that its terrestrial function is much 

 stronger than formerly. Its visual organs do not 

 seem so keen as they did during its aquatic existence, 

 but its olfactory capabilities appear intensified. It 

 possesses a peculiar control over its tail, which it 

 utilises in securing food by circumvolving its prey by 

 that organ. 



In Mexico the Axolotl is very generally cultivated 

 for edible purposes, and is largely vended in the 

 markets. It is said that the flesh resembles in 

 flavour that of the eel, at all events it is considered 

 quite as great a luxury. I have never partaken of 

 the Axolotl, and am afraid the English would be 

 strongly prejudiced against it from an edible point 

 of view, in consequence of its repulsive appearance, 

 and the malodorous effluvia that arises from it at all 

 times. If the flavour of the flesh resembles that of 

 eels, the appearance of the skin certainly does, and 

 I have no doubt the Axolotl would be quite as 

 appetising, if served with suitable condiments. It 

 would be highly injudicious, however, to introduce 

 it to this country, as it would assume a prominent 

 position in the ranks of the numerous army of 

 destructive agents employed by nature to check the 

 population of our waters. 



GEMS AND ORNAMENTAL STONES OF 

 THE UNITED STATES. 



THE Saturday Evening Lecture in the working 

 men's cause was delivered by Professor A. E. 

 Eoote, of Philadelphia, in the Trophy Hall of the 

 American Exhibition, on the above subject, to the 

 largest audience that has assembled during the 

 season. The speaker was introduced with some 

 very complimentary remarks by Mr. F. W. Rudler, 

 curator of the Museum of Practical Geology of 

 Jermyn Street, and president of the Geologists' 

 Association. 



One reason why so little is known about American 

 gems and ornamental stones in Europe is that there 

 is a ready market in America for everything of the 

 gem character that is produced there. Thus far, 

 mining for gems has been of a very desultory 

 character, being principally carried on in connection 

 with mica or other mines, or by farmers and others 



when they have but little else to do. The Emerald 

 and Hiddenite mines of North Carolina, and the 

 Tourmaline mines of Maine, are the only ones that 

 have been worked systematically. Gems are the 

 purest forms of minerals, and in nearly all cases are 

 the result of crystalline action. If the conditions of 

 crystallisation are perfect, all impurities are excluded. 

 Ruskin, in his " Ethics of the Dust," gives a charm- 

 ing illustration of this by supposing the power of 

 crystallisation to be exerted upon the mud of a path 

 of a manufacturing town. The gems peculiar to 

 America are Chlorastrolite, Zonochlorite, and Hid- 

 denite. Chlorastrolite, or Green Star stone, is a 

 species which was discovered by Professor J. D. 

 Whitney, of the United States Geological Survey, 

 about forty years ago. The only place in the world 

 where it is found is Isle Royale, Lake Superior. 

 This island, belonging to the State of Michigan, 

 forty miles long and five miles wide, and about 

 twenty miles from the mainland, is composed of 

 amygdaloid trap, in the almond-shaped cavities of 

 which the gem principally occurs. This green stone 

 radiates from a centre, and shows a beautiful cha- 

 toyance similar to cat's-eye, crocodilite, and other 

 fibrous minerals. In 1S6S, when instructor in 

 chemistry in the University of Michigan, I led a 

 party from the university that camped for several 

 months on the island. 



For the first time the Chlorastrolite was found in a 

 vein stone associated with native copper and Epidote. 

 The best specimen ever found was secured by our 

 party, and is now in Mr. Foote's possession. The 

 second best one belongs to Mr. Morrison, of London, 

 and the next best one, so far as I know, belongs to 

 an American lady resident in London. About ,£300 

 worth are sold annually. Zonochlorite is a green 

 banded stone, similar to Chlorastrolite in composition, 

 but discovered by me at Nespigon Bay, on the north 

 shore of Lake Superior. The full description was 

 published in the Transactions of the American Associ- 

 ation for the Advancement of Science, in 1872. It 

 is an entirely novel stone ; hardness about 7, takes 

 a very high polish, and if it could be found in 

 sufficient quantities would undoubtedly be extensively 

 used. Hiddenite is a green variety of the well- 

 known species Spodumene. A yellow variety from 

 Brazil has been cut as a gem for many years. This 

 variety has been known for about seven years, and is 

 fully as beautiful and valued as highly as the diamond. 

 It occurs in connection with emeralds in North 

 Carolina. The locality is worked by a stock 

 company, and produces about ,£500 worth of hid- 

 denite and ,£600 worth of emeralds annually. One 

 of the finest of these emeralds is in the Brithh 

 Museum. The fullest series of them is in the 

 collection of C. S. Bement, of Philadelphia. One 

 weighs 8i| oz., within a quarter of an ounce of the 

 weight of the most celebrated emerald in England. 

 Of gold quartz, about^2S,ooo worth is sold annually. 



