170 Scientific Intelligence. 



The authors discuss also the force and velocity of falling 

 masses, taking as data the accepted Gunnery tables, and make 

 out that, owing to the resistance of the atmosphere, a velocity of 

 about 720 feet a second is the greatest attainable by a rough flat- 

 sided rock, a square yard in section, and nearly 4000 lbs. in mass ; 

 " such a mass projected from a height of 8000 feet above the sea- 

 level, with a vertical speed of 8500 feet per second, will reach a 

 height of 24,500 feet above the sea-level; and it will return to the 

 earth from that height with a speed of V20 feet per second, which 

 speed it will nearly have attained after it has fallen about half 

 this height." The object of the calculation was to prove that the 

 numerous deep cylindrical holes in the ground were not made by 

 the falling of stones (a view presented in a paper by Mr. Odium) 

 but to some other cause, probably the uprooting of trees. J. d. d. 



4. Die Miner alien der Syenitpegmatitgdnge der SiXdnorwegis- 

 chen Augit- und Nephelin syenite / by W. C. Beoggeb, 235 and 

 663 pp., with 27 plates and 2 geological charts. Leipzig, 1890 — 

 Zeitschrift fur Krystallographie und Mineralogie, vol. xvi (Wm. 

 Engelmann). — It would be difficult to find in the whole range of 

 mineralogical literature another monograph of such exhaustive 

 thoroughness, so rich in new facts and descriptions of new species 

 and devoted to a region of such unique interest as this weighty 

 volume by Professor Brogger. The reader is impressed more 

 and more as he turns over the pages with the vast amount of 

 labor here expended and the rich results which the author has 

 attained. It is impossible here to do more than indicate in the 

 briefest manner the scope of the work. It is divided into a 

 general and a special part. The first part (235 pp.) takes up the 

 geological relations of the pegmatite veins of the Christiania 

 region, giving a general survey of the geology with the 

 several types of eruptive rocks here developed; this is followed 

 by an account of the geology of the syenite and nephelite-syenite 

 veins of the special region under examination, namely that be- 

 tween the Christiania and Langesund fjords. This region has 

 long figured, somewhat inaccurately, in mineralogical text-books 

 under the name of Brevig, a place, however, which lies just out- 

 side its proper limits. This latter part of the subject carries us 

 over a most instructive discussion of the paragenesis of the min- 

 erals peculiar to these veins. 



The special portion of the work (655 pages), which forms the 

 bulk of the volume, is devoted to the minute description of 

 the mineral species, 73 in number. How rich this is will be in 

 part appreciated from the fact that some ten new species are 

 here described, while of many old species we have monographs 

 of the first importance. Of the new species, a number have 

 already been briefly characterized in this Journal (xxxv, 416) 

 from a preliminary article by the author published in 1887. 

 These are: Barkevikite, calciothorite, melanocerite, nordenskiold- 

 ine, rosenbuschite. Besides these we have descriptions of the 

 following : Hambeegite, a borate of beryllium in orthorhombic 



