690 



SCIENCE. 



[Vol. II., No. 42. 



such boats sometimes act alternately, the one hauling, 

 while the other is getting a new position ahead. The 

 advantages thus secured are, that the propelling craft 

 is not detained at either end of the line of trans- 

 portation; that transshipment and the breaking of 

 bulk are avoided ; that the rapids are surmounted with 

 comparative ease; that canal-boats are thus trans- 

 portable from river to canal, and the reverse, making 

 long trips through river and canal, and thus saving 

 expense of repeated handliag of merchandise. This 

 system is pi-oposed for use between Aries and Lyons. 

 The avithor proposes the connection of Aries and 

 Marseilles by a canal, and the continuation of this 

 system through the waterway thus formed. — {Mem. 

 soc. ing. civ., April.) B. H. T. [385 



AGKICULTURE. 



Hill-culture of potatoes. — Experiments by 

 Wollny having led to the conclusion that hill-cul- 

 ture was superfluous, or even injurious, on light 

 soils, Schleh has made experiments with potatoes 

 which in general have corroborated Wollny's conclu- 

 sion. — {Biedermann's centr.-blatt., xii. 4S3.) H. P. A. 



[386 



Proteine of maize-ensilage. — Stutzer finds, that, 

 in the preparation of ensilage from maize, the proteine 

 is largely broken up into products which are not pre- 

 cipitated by copper hydrate, and which are probably 

 of inferior nutritive value. Jordan has made the 

 same observation in experiments ■ at the Pennsylva- 

 nia state college. — (I6M., xii. 497.) H. P. A. [387 



Nitrification in the soil. — Nitrification is depend- 

 ent on the presence of oxygen, and Schlosing has 

 shown that a diminution of the amount of oxygen 

 present decreases the rapidity of the change. Such 

 a diminution of the amount of oxygen in the soil is 

 effected by the presence of organic matter, which 

 unites with it, forming carbonic acid, and thus acts, 

 as D^h^rain and Maguenne point out, to moderate 

 the rapidity of nitrification, and so to prevent a loss 

 of nitrates in the drainage-water. The same authors 

 explain in this way the greater richness in nitrogen 

 of unfilled land, and claim that the presence of or- 

 ganic matter is necessary in order that the soil shall 

 gain nitrogen from natural sources. — {Ibid., xii. 

 506.) H. p. A. [388 



MINERALOGY. 

 Albite. — Des Cloizeaux gives the results of the 

 optical examination of a large number of specimens 

 of albite. Although this mineral is the most con- 

 stant of all the felspars in its chemical composition, 

 its variations in optical properties are great, and 

 dependent upon the homogeneity of the material, 

 the nmnber and arrangement, of the twin lamellae, 

 and, without doubt, upon the circumstances of tem- 

 perature and pressure at which tlie crystals were 

 formed. The following are the properties of the 

 purest and most transparent crystals, which may be 

 regarded as normal : the plane of the optic axes is 

 normal to a surface truncating the acute edge between 

 oPand oa P CD, and making an angle of 101°-102° 

 with the base ; the acute bisectrix is always positive, 



and nearly normal to the edge oP and co P co ; the 

 axial angle for red !u oil is about S0°-S5°, ordinary 

 dispersion p < " ; the obtuse bisectrix is always nega- 

 tive; the axial angle for red in oil is about 104°-100°, 

 ordinary dispersion p> v ; basal sections give for the 

 angle of extinction 2°-4° on either side of the plane 

 of twinning; on the brachypinnaooidal section the 

 angle of extinction is nearly 20°. The results of the 

 examination of thirty-four ditlerent varieties of albite 

 are given, many of them accompanied by chemical 

 analyses. — {Bull. soc. mln., y\. $:'.).) s. L. p. [389 



METEOROLOGY. 



Meteorology in China. — Dr. Doberck of the 

 Hong Kong observatory proposes to study the clima- 

 tology of the region, to determine the magnetic con- 

 ditions, and to investigate the magnetic attraction of 

 various mountains and hills in the vicinity. It is 

 probable that he will endeavor to arrange for the 

 receipt of regular reports from neighboring observa- 

 tories with the object of making weather forecasts. — 

 (Nature, Sept. 27. ) w. u. [390 



Hygrometer studies. — A good hygrometer which 

 can be used in place of the wet- and dry-bulb ther- 

 mometers, and be equally convenient, but more accu- 

 rate in cold weather, is one of the needs of practical 

 meteorology. Comparative observations of the psy- 

 chrometer and the improved hair hygrometer, as 

 manufactured by Hottinger, have been made at 

 Breslau by Dr. Galle since 18S0. As a result, he 

 states, th.at if the saturation-point is determined at 

 intervals of from eight to fourteen days, and the in- 

 strument carefully cleaned when necessary, the rela- 

 tive humidity can be obtained with as great accuracy 

 as with the psychrometer, and in winter with greater 

 accuracy. Unfortunately, there still remains in the 

 instrument the liability to unexpected changes in 

 the saturation-point, and in tlie working of the me- 

 chanism; so that a psychrometer must be at hand 

 for the purpose of comparison. — {Preuss. stat., Ixxi. ; 

 Ergeh. met. beob. konigl. met. inst., 1882.) w. u. [391 



GEOGRAPHY. 



Investigations in Thibet. — At the suggestion of 

 Gen. Walker, geodesist-in-chief to the survey of India, 

 an interesting exploration is about to be undertaken 

 by one of the pundits attached to the survey. This 

 pundit was a companion of the famous Nain Singh, 

 and succeeded, in the midst of a thousand obstacles 

 in the eastern part of Thibet, in recording and pre- 

 serving his itineraries, and obtaining many latitude 

 observations. Thanks to his researches, an area three 

 times as extensive as France can be to a certain ex- 

 tent corrected, and mapped with tolerable accur.acy. 

 The great Thibetan problem as to the relations of 

 the Dzang-bo Kiver are probably settled by his work, 

 from which it would appear that this belongs to the 

 head waters of the Brahmaputra rather than (as for- 

 merly supposed ) to the Irawadi River. — {Hull. soc. 

 geogr. Mars., June. ) w. h. d. [392 



