THE WEST AMERICAN SCIENTIST. 33 



LEUCITE FROM LOWER CALIFORNIA. 



The history of leucite is very interesting. Some thirty years ago Humboldt 

 made the general statement that leucite occurred nowhere outside of Europe. Curi- 

 ously enough, until within a few years this statement lield good. In 1874, how- 

 ever, Vogelsang found it in an Asiatic basalt, and in 1870 Zirkel announced its 

 discovery in Wyoming Territory. 



Although the leucite was invisible to the naked eye, Zirkel's discovery was 

 regarded as so important that the locality was named by the U, S. Geological Sur- 

 vey the Leucite Hills. An interesting commentary on the influence of modern 

 science is furnished by a name so given. 



Another extra-European locality for leucite is now announced by Von Chrust- 

 schoff, who finds it in a lava in the vicinity of the extinct volcano ' Cerro de las Vir- 

 gines' in Lower California. The rock consists of an ash-gray ground-mass sprinkled 

 with rounded spots of brownish-black obsidian or glass, and with light specks of 

 leucite. These light specks are shown by a lens to have a rounded octagonal 

 outline. 



The leucite is remarkably clear and fresh, and shows in polarized light the well 

 known twining structure, even better marked than in the leucite of the Vesuvian 

 lavas or of the Laacher-See. While generally in rounded masses, the smaller indi- 

 viduals are often clearly octagonal in outline. The microscope shows the leucite to 

 contain many inclusions, among which are augite, apatite olivine, plagioclase, mag- 

 netite, nepheline and glass inclusions and bubbles. — [H. C. Lewis. 



TREE PLANTING IN THE UNITED STATES. 



From a paper on the woods of the United States and their destruction, in the 

 February Century, Mr. J. E. Chamberlain sums up as follows : *' The reasonable 

 conclusion of the whole matter would seem to be that while there is no serious 

 menace to the eastern half of the United States through the loss of forests, there is 

 good reason to urge the preservation of as much of them as possible and the encour- 

 agement of new plantations ; while in the western half of the country the immedi- 

 ate withdrawal from sale of the whole body of forests belonging to the Government 

 is highly desirable There should be an exhaustive inquiry, at the hands of a com- 

 petent Government commission, into the subject of the extent of forests belonging 

 to the Government, their location, value, character, etc., the proportion of private 

 lands now wooded, and the apparent' dependence or independence, as the case may 

 be, of all sections of the country upon the modifying effect of forests. Exact infor- 

 mation is now needed, which could scarcely be obtained except through the efforts 

 of such a commission. 



"Sentimental considerations, I suppose, are to be held secondary to the practi- 

 cal in the matter ; but they are powerful, and should be aroused in behalf of no ob- 

 ject more readily than the woods, which have occupied so large a place in the senti- 

 mental life of man from the earliest times." 



