152 



SCIENCE. 



[N. S. Vol. IX. No. 213. 



The great similarity of liquid ammonia and 

 water in their dissociating power has led to a 

 thorough study of the properties of liquid am- 

 monia. It was found that in a considerable 

 number of cases the nitrates of the metals were 

 acted upon, when in solution in liquid am- 

 monia, by the ammonium salts and a salt pre- 

 cipitated as a result of the metathetic reactions, 

 if the salt formed was insoluble in ammonia. 

 It was also found that many of the physical 

 constants, which in the case of water are so en- 

 tirely different from those of all other liquids, 

 are almost as strongly characterized in the 

 case of ammonia as in that of water. ' On 

 the Constitution of the Phenylhydragoues : ' 

 By P. C. Freer. ' Note on the Action of 

 Liquid Hydriodic Acidon Ethylether : ' By 

 F. G. Cottrell and E. R. Eogers. In this case 

 there was a partial conversion of the ether 

 into ethyliodide. ' Contributions to our Knowl- 

 edge of the Oil of Lemon- Grass : ' By W. Stiehl. 

 Isolation of the three aldehydes : Citriodoric 

 aldehyde, Geranial and Allo-lemonal. The 

 American Chemical Journal will hereafter ap- 

 pear monthly, and two volumes will be issued 

 yearly. J. Elliott Gilpin. 



We have received the first issue of Science 

 Work, a Monthly Review of Scientific Literature, 

 edited by Mr. Waller Jeffs and published at 

 Manchester by Messrs. Robert Aiken & Com- 

 pany. It is stated in the introduction that the 

 Journal ' will aim to give a general review of the 

 world of science and present the reader as it were 

 with the cream of the scientific press,' but we 

 fear that it will be diflicult to do this withiu the 

 limits of eight pages published twelve times 

 a year. 



Natural Science, now published by Mr. Henry 

 J. Pentland at Edinburgh, and still edited anon- 

 ymously, but under new auspices, opens with 

 the issue for January its fourteenth volume. 

 The general character of the contents, which 

 has always made Natural Science interesting 

 and profitable, is well maintained. 



SOCIETIES AND ACADEMIES. 



GEOLOGICAL SOCIETY OF WASHINGTON. 



At the regular meeting of this Society held in 

 Washington, D. C, January 11, 1899, Mr. Wil- 

 lard D. Johnson, U. S. G. S., read a paper on 



' Subsidence Basis of the High Plains,' and Dr.C. 

 Willard Hayes, U. S. G. S., one on the 'Lake Re- 

 gion in Central America.' Dr. Hayes' paper was 

 based upon observations made recently in Cen- 

 tral America while working under detail as 

 geologist to the Nicaraguan Canal Commission. 

 Abstracts of both papers follow. 



Subsidence Basins of the Eigh Plains. — The 

 Great Plains structural slope has been super- 

 ficially modified by streams from the Rocky 

 Mountains, in three stages of gradation — a first 

 stage, in which a hard-rock topography was de- 

 veloped by degradation ; a second, in which 

 this topography, by aggradation, became buried 

 under an alluvial waste sheet to depths within 

 its valleys as great as 300 feet ; the third and 

 present stage, in which the mountain streams 

 are again engaged in cutting and have trenched 

 the aggradation plain with parallel valleys, 

 wide apart. But left thus above grade, this 

 flat surface, in the greater part, has been eroded 

 also by the drainage from its local precipita- 

 tion. In notable excejjtion is a transverse, mid- 

 slope belt. Here the flat surface suffers no 

 erosion from its local precipitation and has vir- 

 tually no local drainage. It therefore stands 

 in light relief Transected by the mountain 

 streams into broad plateaus of faint elevation, it 

 forms a belt of residual tables or upland flats of 

 survival. The Staked Plains plateau, of north- 

 western Texas, constitutes the best individual 

 example. These are the High Plains — to some 

 extent locally so-called. The Great Plains slope 

 has a graduated climate — from humid to arid, 

 east to west. The High Plains correspond in 

 position to its ' subhumid ' belt. 



In the arid belt to the westward the vegeta- 

 tion — of grass and brush — grows in tufts. It 

 affords but slight protection against the feeble 

 precipitation, and the surface is conspicuously 

 eroded. Upon the High Plains, within the sub- 

 humid belt, however, vegetation is wholly of 

 grass, which forms a universal, close-knit sod. 

 This vegetal cover affords complete protection 

 against the considerable local precipitation. 

 The High Plains are distinctively the ' short- 

 grass country.' As a residual topographic belt, 

 within the climatic belt, they are held by their 

 sod. The local precipitation — so much of it as 

 does not evaporate — is absorbed. 



