Febkuaey 5, 1897.] 



SCIENCE. 



229 



Carl Barus describes a form of interferential 

 induction balance and details some experiments 

 to show wbat may be accomplished with it. 

 This apparatus involves the principles of Mich- 

 elson's interferential refractor, the iron cores of 

 two like helices at right angles to each other 

 being fastened at one end and free to move in 

 the direction of the axes at the other. The in- 

 terference fringes are visible whenever the ex- 

 cursions of the free ends of the cores are either 

 zero or vibrating in the same phase, amplitude 

 and period to and from the point of conver- 

 gence ; for other phases the fringes vanish 

 more or less fully. In the course of one series 

 of experiments to test the speed of transmission 

 of electric impulses from one helix to another, 

 the author concludes that an arrangement 

 could be made which would indicate the rets(f- 

 ■dation along something over a single knot of 

 wire of high capacity inserted between the 

 helices. This retardation would be exhibited 

 by the passage of one yellow interference 

 fringe across the spider lines of the telescope. 



John Trowbridge and Theodore M. Richards 

 discuss the multiple spectra of gases, as a con- 

 tinuation of their work on the spectra of argon 

 described in the January number. They have 

 experimented upon the spectra of nitrogen, 

 hydrogen and other substances, with the re- 

 sult of confirming their former conclusion that 

 the electrical conditions of the circuit have an 

 essential influence in determining the character 

 of the spectra obtained. 



Theo. Holm gives the third paper of his 

 studies of the Cyperacese. This is devoted to a 

 morphological and anatomical study of Carex 

 Fraseri and is illustrated by a plate. 



T. A. Jaggar, Jr., describes "a simple me- 

 chanical device for inclining a preparation in 

 the microscope in petrographical study. It 

 allows, for example, of a rapid determination 

 of the optical orientation in feldspar sections 

 and similar cases. 



A. E. Verrill has two papers ; the first on the 

 nocturnal protective coloration in mammals, 

 birds, fishes and insects as developed by nat- 

 Tiral selection. In this he calls attention to the 

 fact that the co^pr of many animals is such as to 

 give them protection at night at the time when 

 it is most called for. This is illustrated by a 



number of interesting examples. The second 

 paper discusses the nocturnal diurnal changes 

 in the color of certain fishes and of the squid 

 (Loligo), with notes on their sleeping habits. 

 "When at "Wood's Holl, Massachusetts, in the 

 laboratory of the United States Fish Commis- 

 sion, in 1885-1887, the author had an opportu- 

 nity to make observations on the marine ani- 

 mals in the aquaria between midnight and two 

 o'clock a. m. Some remarkable cases of 

 change of color were then noted. It is re- 

 marked that most fishes sleep very lightly and 

 are aroused by almost imperceptible vibrations 

 of air or water. Some of the fishes take re- 

 markable attitudes while asleep. 



The same author gives additional notes in re- 

 gard to an enormous octopus, as it was sup- 

 posed to be, which was thrown up on the 

 Florida coast some weeks since. The body as 

 preserved is some 21 feet long and is esti- 

 mated to weigh between six and seven tons. 

 The name Octopus giganteus is proposed for it. 



O. C. Marsh has an article on the Stylinodon- 

 tia, a sub-order of Eocene Edentates, in which 

 a description is given, with numerous figures, of 

 Btylinodon mirus, the type specimen as described 

 in May, 1874. In regard to the origin of the 

 Edentates the author repeats his remarks of 

 August, 1877. He concludes by saying that 

 the work of the past two decades has served to 

 confirm the opinion that this group of mammals 

 originated in North America and migrated from 

 there to other parts of the earth where their 

 remains have been found or living representa- 

 tives are in existence. 



The number closes with the usual chemical, 

 physical and geological abstracts and notices. 



AMERICAN GEOLOGIST, JANUARY. 



Sketch of "W. W. Martin, accompanied by a 

 list of official and professional positions held by 

 him and a bibliography, by C. H. Hitchcock. 



' The study of natural Palimpsests,' by G. P. 

 Grimsley, gives a brief historical account of the 

 discoveries in archsean and metamorphic rocks, 

 and the methods employed in their study. 



F. "W. Sardeson continues his discussions on 

 the Galena and Maquoketa series begun in the 

 December number. Under the Galena series he 

 recognizes the Beloit and Galena formations, 



