384 



SCIENCE. 



[Vol. XV. No. 386 



and probably did, for many centuries, but there is no satis- 

 factory evidence found in the monuments that there were 

 two distinct mound-building ages. On the contrary, the 

 historical, traditional, and archffiologic testimony is decidedly 

 ia favor of the theory that our prehistoric works are attribut- 

 able to the Indian tribes found inhabiting this country at its 

 discovery, and their ancestors. Cyeus Thomas. 



NOTES AND NEWS. 



Since the article on the Kiowa County meteorites was pub- 

 lished (Science, June 18, 1890), we learn that another mass, 

 weighing 219 pounds, has been found at Brenham Township, 

 Kiowa County, Kan. 



— We leai-n from Nature of June 12 that the measurement of 

 the Rhone glacier in a comprehensive and systematic way has 

 been carried on since 1874 by the Swiss Alpine Club, and the 

 abundant data obtained will shortly be published in separate 

 form. It appears that the glacier was in recession till 1888. but 

 since last year it has been advancing. 



— By the new law on education of 1891, Sloyd is made obliga- 

 tory in all the schools of Norway. The Norwegian Government 

 has invited Mr. Akkel Mikkelsen, director of the Danish Sloyd- 

 training College, to give a course of instruction at Christiania to 

 the teachers of all the training-colleges in Norway. The courses 

 for Sloyd at Naas, in Sweden, will be held from May 37 to July 

 8, from July 29 to Sept. 8, and from Nov. 4 to Dec. 15. 



— The Appalachian Mountain Club has issued a special circular 

 relating to the twenty-fifth field meeting, at the Deer Park Hotel, 

 North Woodstock, N.H. , July 1-8, and excursion to Randolph 

 July 8-14. Further information may be obtained by addressing 

 John Ritchie, jun., Box 3725, Boston, Mass., or J. Allen Crosby, 

 70 Boylston Street, Jamaica Plain, Mass. Members of the club 

 who would be interested in a trip to the Dead River region, Maine, 

 In September or October, visiting Mounts Abram Bigelow, Snow, 

 and Parlin Pond Bald, are invited to communicate with R. B. 

 Giover, 11 Durham Street, Boston, Mass. 



— A noteworthy event in the movement for the higher educa- 

 tion of women, as we learn from the London Journal of Educa- 

 tion, was the laying of the foundation stone of the Janet Clarke 

 Buildings at Trinity College, Melbourne, Australia, on March 17. 

 In 1883, Trinity College authoi-ities decided, with some misgiv- 

 ings, to admit women students to their lectures. The next step 

 was the establishment of a collegiate home, and a house in the 

 neighborhood of the college was rented as a residence for lady 

 students'. To put this home on a permanent basis. Lady Clarke 

 promised a donation of £5,000, which will go far towards defraying 

 the cost of the new building. Sir M. H. Davies has given £3,000 

 as the nucleus of an endowment fund. Miss Hensley, a former 

 student of Newnham College, has been engaged by the council as 

 lady principal of what will be the first Australian women's college. 

 — In the Journal of the Bombay Natural History Society (vol. 

 iv. No. 3) Mr. E. Giles records a cui-ious fact, which ought to have 

 some interest for entomologists. In June, 1888, he was standing 

 one morning in the porch of his house, when his attention was at- 

 tracted by a large dragonfly of a metallic blue color, about two 

 inches and a half long, and with an extremely neat figure, who 

 was cruising backwards and forwards in the porch in an earnest 

 manner, that seemed to show he had some special object in view. 

 Suddenly he alighted at the entrance of a small hole in the gravel, 

 and began to dig vigorously, sending the dust in small showers 

 behind him. "I watched him," says Mr. Giles, "with great at- 

 tention; and after the lapse of about half a minute, when the 

 dragon-fly was head and shoulders down the hole, a large and 

 very fat cricket emerged like a bolted rabbit, and sprang several 

 feet into the air. Then ensued a brisk contest of bounds and 

 darts, the cricket springing from side to side and up and down, 

 and the dragon-fly darting at him the moment he alighted. It 

 was long odds on the dragon-fly, for the cricket was too fat to 

 last, and his springs became slower and lower, till at last bis ene- 



my succeeded in pifining bim by the neck. The dragon-fly ap- 

 peared to bite the cricket, who, after a struggle or two, turned 

 over on his back and lay motionless, either dead or temporarily 

 senseless. The dragon-fly then, without any hesitation, seized 

 him by the hind-legs, dragged him rapidly to the hole out of 

 which he had dug bim, entered himself, and pulled the cricket in 

 after him, and then, emerging, scratched some sand over the hole 

 and flew away ; time for the whole transaction, say, three minutes." 



— In a lecture on "Foam," Lord Rayleigh insisted that foaming 

 liquids were essentially impure, for pure liquids will not foam. 

 For instance: neither water nor alcohol can be raised into a froth, 

 although a mixture of the two may be to a certain extent. Th& 

 addition of gelatine to water in the proportion of 1 in 100,000 de- 

 velops the foaming quality quite noticeably. Of course, the best- 

 known foaming liquid is a solution of soap, such as the children 

 use for blowing bubbles. A liquid foams when its films have a 

 certain durability. In all liquids these films exist, since a bubble- 

 as it rises is covered with a thin film. Now, the most striking, 

 property of films is their tendency to contract, and they may be 

 regarded as being in the condition of a stretched membrane, as 

 of India-rubber, with the diff'erence that the tendency to contract 

 never ceases. An air-bubble will force the air back through the- 

 pipe, and a loop of silk floating on a film will be forced into a 

 circle the moment the film inside it is ruptured. Oil forms a 

 film on the surface of water, and covers it entirely, even it tha- 

 mass of the oil be collected into drops. This is well shown by 

 dropping a particle of oil on to a vessel of water lightly covered 

 with sulphur flour. The sulphur will be irtimediately driven to- 

 the edge by the spreading film. The reason of this is that the- 

 tensiou of the water air film is greater than the combined tensions 

 of the water-oil and oil-air films, and consequently pulls out the 

 oil-film. It is possible to reduce the surface tension of water by 

 mixing it with \ arious substances, such as ether and camphor. 

 Camphor scrapings placed on the surface of pure water enter into 

 vigorous movement, because the dissolved camphor diminishes 

 the surface tension of the water; but, if the water be contami- 

 nated by the least quantity of oil or grease, the motion ceases. 

 Loi-d Rayleigh made several exjjeiiments to find what thickness 

 of oil-film would accomplish this: he found it to be about 14- 

 millionth of a millimetre. This thickness bears to an inch the 

 same ratio that a second of time bears to half a year. Lord Ray 

 leigh explains the calming action of oil on the sea as follows: as 

 the waves advance, the surface has to submit to periodic exten 

 sions and contractions. At the crest of a wave the surface is 

 compressed, while at the trough it is extended. So long as the 

 water is pure, there is no force to oppose this; but, if the surface 

 be contaminated, the contamination strongly resists the alternate- 

 stretching and contraction. It tends always, on the contrary, to 

 spread itself uniformly, and the result is that the water refuses to 

 lend itself to the motion which is required of it. The film of oil 

 may be compared to an inextensible membrane floating on the- 

 surface of the water, and hampering its motion. 



— The visit of the Iron and Steel Institute of Great Britain to 

 the United States in the autumn is likely to be in every way most 

 successful. There will be three different sets of meetings, — the- 

 meetings of the American Institute of Mining Engineers, which 

 take place in New York on Sept. 29 and 30; the meetings of the- 

 Iron and Steel Institute of Great Britain, which take place in the- 

 same city on Oct. 1, 2, and 3: and the international meeting pro- 

 moted jointly by those two societies, which will take place about 

 the middle of October at Pittsburgh. The excursions which have 

 been planned by the American reception committee, of which Mr.. 

 Andrew Carnegie is chairman, provide for about three thousand' 

 miles of free transportation through the United States. Accord- 

 ing to Nature, the principal excursions will take place to the iron 

 ore and copper regions of Lake Superior; to Philadelphia, Harris- 

 burg, and Chicago, wliei-e there are large iron and steel engineer- 

 ing works to be inspected; and to the new iron-making district of 

 Alabama. About three hundred members of the Iron and Steel 

 Institute and one hundred German iron-masters have intimated 

 their intention of taking part in the meetings; and ah-eady many 

 have booked passages in the Hamburg- American Company's: 



