52 



SCIENCE. 



[Vol. It., No. 23. 



By reduction, dioxytriphenylmethan 



/ H CoHjOHX 

 VqHs CbHbOH/ 



is formed. An analogous reaction takes place if 

 resorcine is used instead of phenol. " The resulting 

 resorcine benzein, by reduction, gives tetraoxytri- 

 phenylmethan, — 



With primary aromatic amines, benzotrichloride 

 united readily. "When added to a mixture of di- 

 methylaniline and zinc chloride, it formed malachite 



green, — 



(OH) C„njN"(CH3), 



C 

 C„H5 CcHiNCCHs). 



By reduction, this substance gave the corresponding 



leuko-base, — 



H CbHjNCCH,), 

 C 

 CoHj CcH4l>r(CH,,), 



The base malachite green was easily decomposed, 

 when heated with hydrochloric acid, into dimethyl- 

 amine and benzoyldimethylaniline. This reaction 

 points to the following structure for malachite 

 green : — 



(CH3); 



< 



I 

 . — C — - 



>N (CH3),. 



The action of benzoyl trichloride upon hydroxyl or 

 amido compounds seems, therefore, to be normal to 

 the para position with respect to the amido or the 

 hydroxyl group. — {Ann. chem., ccxyii. 223. ) c. F. M. 



[50 

 GEOLOGY. 



Lithology. 

 The Potsdam and St. Peters sandstones. — 



The surface induration of the friable Potsdam and 

 St. Peters sandstones, as determined by macroscopic 

 observations in 1871-73, was brought to the notice 

 of the readers of Science some time ago (i. 

 146), while a recent interesting paper by Prof. 

 E. D. Irving gives the results of his microscopic 

 investigations on the same subject. Irving finds, 

 as Sorby had previously, that ordinary quartz grains, 

 formerly rounded and worn, have been built out 

 and _supplied with crystal facets from silica depos- 

 ited later on them. He finds that the induration of 

 the above-mentioned sandstones arises from the depo- 

 sition of intersticial quartz cementing the grains. 

 The deposited quartz is found to be optically ori- 

 ented, the same as the enclosed grain, which is dis- 

 tinguished by its cloudiness and worn surface, and 

 frequently by a coating of oxide of iron upon it. 



To the deposition of quartz upon worn quartz 

 grains is ascribed the occurrence of quartz crystals in 

 the Potsdam sandstone described in 1882 by Rev. A. 

 A. Toimg. Credit should have been given by both 

 Irving and Young to Rev. John Murrish for calling 

 attention to the occurrence of quartz crystals in 

 Potsdam sandstone in 1870-72 (Bull. Wise, acad., ii. 

 32), especially since Murrish's observations were dis- 

 credited at the time. 



All quartz crystals in sandstone have not this 

 derivation, as the writer showed for the Lake Supe- 

 rior sandstone in 1880, the crystals of which come 

 from old eruptive rocks owing to the decomposition 

 of the matrix. It is pleasant to find my earlier 

 observations on the surface induration of the Wis- 

 consin sandstones, and the formation in them of 

 quartz crystals, sustained by the much more complete 

 and valuable work of Irving, made, as his was, with- 

 out any knowledge of mine. 



Irving holds that the quartz deposited may come 

 from the action of water on the occasional felspar 

 particles in tlie rock, although sometimes from an 

 external source. He further regards the induration 

 of quartzites and quartz schists as caused by the 

 same deposition of intersticial quartz. — {A^ner. journ. 

 SC, XXV. 401.) M. E. w. [51 



Antase as an alteration product of titanite. — 

 The titanite in a biotite amphibole granite from the 

 Troad was found by Mr. J. S. Diller to be replaced 

 by a light wine-yellow to honey-yellow mineral, 

 showing, under the microscope, quadratic and rhom- 

 bic sections. The former are isotropic, and have a 

 well-marked cleavage parallel to their sides; the 

 latter are strongly doubly refracting, extinguish 

 parallel to the diagonal, and have one cleavage par- 

 allel to the short diagonal and another to the edges. 

 In order to isolate the substance, the finely pulver- 

 ized rock was separated into two portions, one of 

 hghter and the other of heavier specific gravity than 

 2.72, by means of the potassium-iodine-mercury solu- 

 tion. The yellow mineral was found in the second 

 portion, which contained also iron ore, zircon, and 

 apatite. The ore was removed by the electro-magnet, 

 and the apatite by nitric acid. By means of the cad- 

 mitim-boron-tungstate solution it was shown that the 

 yellow mineral had a specific gravity between 3.6 and 

 4.5. Some grains were picked out, and found to be 

 insoluble in hot aqua regia. 



The mixed zircon and yellow miner.1l powder gave 

 a reaction for titanium, while the pure zircon would 

 not: hence it was inferred that the mineral contained 

 titanium. Its angles were found to be 98° 24' and 

 136° 16', while the corresponding ones of antase are 

 97° 51' and 136° 36'. From its optical, chemical, 

 and crystallographic characters, it was then inferred 

 that the yellow mineral was antase. — [Neues jahrb. 

 miner., 1883.) m. e. w. [52 



GEOGEAPHX. 



{South America.) 



The Puno railroad, Peru. — Dr. R. Copeland 

 gives a readable account of a journey over this re- 

 markable railroad from its beginning at Mollendo on. 

 the coast, through Arequipa, to Puno on Lake Titi- 

 caca, and of his farther travels by boat on the lake, 

 and by stage, beyond to La Paz in Bolivia. The 

 features that attracted his special attention were the 

 deep, narrow valleys followed by the road in its sharp- 

 windings while ascending from one pampa level to 

 the next; the broad, flat, barren pampas at great and 

 greater altitudes; and the superb views of the vol- 

 canic peaks and ranges of the Cordillera, — Misti^ 



