516 



SCIENCE. 



[N. S. Vol. XI. No. 274. 



quarter ' of the gneissic uplands of Sutherland 

 (N. Scotland). 



MOUNTAINS AND VALLEYS. 



RiCHTEE of Graz writes on ' Gebirgshebung 

 und Thalbildung ' {Zeitschr. dent. u. bsterr. Al- 

 penverein, xxs, 1899, 18-27), re-afBrming the 

 modern view that the bold forms of the Alpine 

 summits result from the carving of valleys be- 

 tween them. He calls attention to the rough 

 equality of height among the peaks of the Alps, 

 and discusses the relation of peak height to 

 valley spacing. He points out that in lofty 

 ranges, the valleys must be relatively far apart, 

 in order to allow the intervening mountain to 

 rise to a great height. Before the greater up- 

 lift of the Alps, when the relief of the surface 

 was less, streams and valleys were probably 

 more numerous and closer together. As eleva- 

 tion progressed, some streams deepened their 

 valleys faster than others and the side branches 

 of the more active streams tapped the less 

 active streams at many points and practically 

 destroyed them; thus only the stronger streams 

 survived in the deeper valleys. The rapid 

 erosion of cliffs has reduced the mountain 

 sides to a relatively uniform declivity, and the 

 peaks are defined by the intersection of slopes 

 propagated upward from the stream lines. 

 Glacial action is briefly referred to as having 

 produced trough-like channels whose side walls 

 are steeper than the preglacial valley slopes 

 which rise above them. 



THE MEUSE IN BELGIUM. 



After the Meuse trenches the Ardennes, it 

 turns eastward along the strike of the Carbo- 

 niferous rocks, receiving the Sambre from the 

 western extension of the same geological belt. 

 On this longitudinal course, streams of consid- 

 erable length are received from the valleys of 

 the Ardennes on the south, but the divide on the 

 .north lies close to the Sambre-Meuse, except at 

 a few points where it locally loops northward. 

 The streams that drain these loops receive a 

 number of barbed headwaters which flow away 

 from the Meuse valley before turning around 

 towards it. The barbed headwaters are ex- 

 plained by Cornet as having once belonged to 

 streams that flowed continuously northward. 

 They have been captured by side streams of the 



Meuse in consequence of the depth to which its 

 longitudinal valley has been cut (Ajin. Soc, 

 geol. de Belgique, xxvii, 1899). The beheaded 

 streams, northward of their diverted head- 

 waters, and their special relations to the valleys 

 that they occupy are not described. 



W. M. Davis. 



NOTES ON INORGANIC CHEMISTBT. 

 A PAPEK was read by Dr. Orme Masson be- 

 fore the recent Melbourne meeting of the Aus- 

 tralasian Association on the use of Iceland spar 

 as a standard in volumetric analysis, and is re- 

 printed in the Chemical News. In Masson's 

 method the pure spar in cleavage crystals is 

 weighed in a beaker and then treated with 

 20 cc. of the acid to be standardized ; after the 

 first effervescence is over the whole is heated to 

 boiling for an hour. The now perfectly neutral 

 calcium chlorid is decanted ofT, the undissolved 

 spar carefully rinsed in the beaker, dried at 

 110° and weighed. The loss in weight repre- 

 sents exactly the strength of the acid compared 

 with normal, as 20 cc. of normal acid dissolves 

 exactly 1 gramme of calcium carbonate. The 

 method presents the advantages over the usual 

 Iceland spar method, that there is no indicator 

 used and no titrating of excess of acid with 

 alkali — furthermore the crystals are less hygro- 

 scopic than the powder. The method has a 

 further advantage over other methods in that 

 few compounds can easily be obtained in so 

 pure a state or of so definite composition as Ice- 

 land spar. 



In a recent number of the Bulletin of the 

 French Chemical Society Professor Moissan has 

 described a definite phosphid of calcium with 

 the formula CajFj. It may be formed by the 

 reduction of calcium phosphate with carbon 

 in the electrical furnace, or by the direct action 

 of phosphorus vapors on calcium. In the for- 

 mer case it is crystalline, in the latter amor- 

 phous ; in both a dark red solid. It is decom- 

 posed by water with the formation of phosphin, 

 PH,, in this respect resembling a number of 

 binary compounds of calcium, such as calcium 

 hydrid with evolution of hydrogen, calcium car- 

 bid with evolution of acetylene, calcium nitrid 

 with evolution of ammonia. Lebeau has also 



