142 



THE POPULAR SCIENCE MONTHLY. 



" IndifTerent," is ejaculated at each bead, till 

 the big terminal one is reached, and that 

 decides the question. Answers are given in 

 conversation, bargains are made or refused, 

 and serious acts are undertaken under the 

 guidance of this formula. Another way is to 

 thrust a knife into the leaves of the Koran 

 or one of the poetical books, and be guided 

 by what is found at the place. The diviners 

 are real quacks, and gain their success by 

 working on the fears of the people. The 

 guilty party in a scandal or criminal inquiry 

 in his nervousness is provoked to do some 

 act that brings about his detection. 



The Nature of Diatoms.— The curiously 

 beautiful microscopic objects called diatoms 

 can be found in the mud at the bottom of 

 all pools of water. They were formerly 

 regarded as animals, but are now classed 

 among plants. Professor W. Mattieu Will- 

 iams discovered their vegetable character 

 thirty years ago by an observation which 

 amounted to a demonstration. The white 

 quartz pebbles in his aquarium became 

 coated with a brown growth, caused by 

 the development of these organisms, and at 

 the same time evolved bubbles of gas. In 

 the course of a few days he found an inch 

 of the vertical space of the test-tube which 

 he fixed to catch it filled with this gas, and 

 it was proved by burning wood and other 

 experiments to be nearly all oxygen. Ani- 

 mals expire carbonic acid, plants expire 

 oxygen. Therefore the diatoms were plants. 



A Rock-scalptnred City. — Montpellier-le 

 Vieux is the name given to a curious city-like 

 group of weather-sculptured rocks, which 

 M. E. A. Martcl has described to the French 

 Academy of Sciences. It is near Millau, 

 in Auvergne, France, and about twenty-five 

 hundred feet above the sea. It is composed 

 of a mass of isolated rocks, averaging per- 

 haps about two hundred feet in height, so 

 similar to embattled towers that one group 

 has been called the Citadel; around this 

 mass are five depressions three or four hun- 

 dred feet deep, of which one resembles an 

 amphitheatre, a second a necropolis, a third 

 a parade-ground, and another a regularly 

 laid out city quarter with public monuments, 

 gates, straight streets and intersections sug- 

 gesting at once such places as Pompeii, Car- 

 nac, and Persepolia. The whole, occupying 



about five hundred acres, is surrounded by 

 a rocky formation having the aspect of a 

 wall three or four hundred feet high. The 

 ravines under the bases of these walls might 

 be regarded as fosses, and the scattered 

 groups of rocks in the neighborhood as the 

 fortifications of outer lines of defense. 



Idiosyncrasies of Plants. — An English 

 reviewer of a book by Mr. Charles Roberts, 

 called " The Naturalist's Diary," mentions 

 the idiosyncrasies of certain plants and ani- 

 mals as a feature to which more attention 

 might be given. Thus, a quantity of seed 

 taken from the same plant at the same time, 

 and sown under the same conditions so far 

 as possible, will nevertheless exhibit very 

 great variation in the length of time re- 

 quired for germination. The fact enforces 

 the circumstance that the same amount of 

 aggregate temperature and of water-supply, 

 the same conditions of soil, etc., do not 

 necessarily imply corresponding identity of 

 result. The same thing happens in trees. 

 Every one knows how some individual 

 horse-chestnut trees are year by year more 

 precocious in their development than their 

 fellows. It sometimes happens, too, that 

 one branch of one tree is considerably in 

 advance of the others. Some persons might 

 call these cases exceptions, but they are 

 hardly that. Since they are connected with 

 the main body of habitudes by every pos- 

 sible gradation, they are to be considered as 

 extremes rather than as exceptions, and 

 therefore to be included in the making up 

 of averages. 



NOTES. 



Presidknt Peckham, of the Natural His- 

 tory Society of Wisconsin, has been investi- 

 gating the mental habits and peculiarities 

 of wasps. On the question whether these 

 insects have much sympathy with one an- 

 other, he says : " To be sure, when we 

 caught numbers of them, and painted them 

 within the cage, they at once went to work 

 to clean each other, and this shows that 

 they have some desiie to aid and comfort 

 their friends. But we have often seen them 

 continue to eat, with entire composure, near 

 the body of one of their number that had 

 just been crushed to dcalh ; and they fre- 

 quently fall upon a dead relative, cut it up, 

 and carry it into the nest to feed their 

 young." 



