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THE POPULAR SCIENCE MONTHLY. 



these oue was on the gar-pike. The gar- 

 pike is kuown to science as a very ancient 

 type of ganoid fish a sort of living fossil. 

 The young gar has two tails, the one ser- 

 pent-like and the other fish -like. The 

 former is snake-like in motion as well as in 

 form. It is largest and most active in the 

 very young. As the fish grows, it aborts, 

 and at adult age it is obsolete. Prof. Wild- 

 er's investigations show that this temporary 

 tail is a vestige, a reminiscence, a survival. 

 The ancestor of the gar was a reptile, and 

 the young fish still carries the ancestral 

 reptilian tail. Another paper by the same 

 author was on 



T3ie Sirenia. The name we have bor- 

 rowed from Greek mythology, according to 

 which the sirens were young maidens who 

 sat on the shores of a certain island near 

 Italy, and "sang with bewitching sweetness 

 songs that allured the passing sailor to draw 

 near, but only to meet with death." Why 

 the manatee and the dugong should be 

 called sirenia is not apparent on the sur- 

 face, for they are not graceful, neither are 

 they sweet singers ; besides, they bear no 

 enmity to the human race. Externally the 

 sirenia are whale-like, but internally they 

 are pachyderm-like. Prof. Wilder has dis- 

 sected a fuetal dugong (secured in Australia 

 by Prof. Ward), and from a study of its 

 structure he concludes that the sirenia are 

 not modified whales, but modified pachy- 

 derms, aud that they are descended from 

 some ancient hippopotamoid quadruped. 



Porcelain-Clay. A paper was read by 

 Prof. Cox, Indiana State Geologist, on a 

 white clay resembling kaolin, lately discov- 

 ered in Lawrence County, Indiana. A full 

 synopsis of this paper was published in the 

 Tribune, from which we derive the following 

 particulars : The Lawrecne County bed of 

 porcelain-clay occupies the position of the 

 Archimedes limestone belonging to the Ches- 

 ter group. This limestone has been entire- 

 ly removed where the clay is found, by the 

 action of water charged with hydrated sili- 

 cate of alumina and carbonate of protoxide 

 of iron. The water which held these sub- 

 stances in solution is supposed to have con- 

 tained alkaline carbonates, with carbonic 

 acid in excess. It is thus that the water 



was enabled to dissolve the limestone, and 

 by an interchange of chemical constituents, 

 the hydrated silicate of alumina was pre- 

 cipitated and the lime carried off in solu- 

 tion. The carbonate of protoxide of iron 

 also continued in solution until it met with 

 a sufficient amount of oxygen for its peroxi- 

 dation and precipitation. The upper por- 

 tion of the clay, from one to twelve inches 

 in thickness, is of a light cream-color, free 

 from grit and laminated. Then follow 

 from four to five feet of pure white clay, 

 also free from grit. Beneath this is a clay 

 of similar quality, but slightly stained at 

 the joints with oxide of iron. Prof. Cox 

 calls the white clay Indianaite ; it has a 

 composition of 12 to 14 per cent, water, 42 

 to 45 per cent, silica, and 36 to 39 alumina. 

 The area of the deposit is known to be at 

 least 42 acres, and there is little doubt that 

 it is much more extended. Indianaite is 

 now used in the porcelain potteries at Cin- 

 cinnati, and ware made of it is fully equal 

 to the best English ironstone pottery. 



Are Potato-Bngs poisonous? A paper 

 by Augustus R. Grote and Adolph Kayser 

 stated the results of an investigation of the 

 supposed poisonous properties of the po- 

 tato-bug. A quantity of the bugs wei'e sub- 

 mitted to distillation with salt-water, so as 

 to increase the temperature, the product 

 being four ounces of liquid from one quart- 

 measure of the bugs. This liquid had an 

 alkaline reaction, owing to the presence of 

 free ammonia and carbonate of ammonia. 

 It was perfectly clear, and had a very offen- 

 sive odor. A tincture of the dari/phora was 

 next prepared, the bugs having been di- 

 gested for twenty-four hours in alcohol, 

 which was then evaporated at a gentle heat. 

 The tincture had a decided acid reaction, 

 was brown in color, odor not offensive. On 

 introducing into the stomach of a frog about 

 half a cubic centimetre of the liquid and of 

 the tincture separately, no effect was ob- 

 served. Hypodermic injection of the dis- 

 tilled liquid was in like manner unattended 

 by injurious results, but the tincture proved 

 fatal when administered in this way. The 

 leg, into which the tincture was injected, 

 was quickly paralyzed, and in thirty min- 

 utes the heart had ceased to beat. This 

 tincture, though highly concentrated, con- 



