226 



SCIENCE. 



[Voi„ I., No. 8. 



Relation bet-wreen viscosity and galvanic re- 

 sistance. — Mr. L. Grossman applies formulas de- 

 duced by him in a former article (Ann. phys. chem., 

 1882, xvi.) to the analysis of experiments made by 

 Grotrian, Kohlrausch, and others, on the temperature 

 curves of internal friction and galvanic resistance in 

 fluids, obtaining what he considers accurate deter- 

 minations of twenty-five temperature co-efiBcients for 

 each of these properties in solutions of six different 

 salts; hence he concludes, that, for these solutions, 

 the temperature curves of these two properties are 

 equal. — (Ann. phys. chem., 1883, i.) J. T. [482 



Molecular theory of magnetization. — D. E. 

 Hughes, in a lecture before the Institution of me- 

 chanical engineers, says that if a coil be placed at 

 right angles with a plane circuit containing a soft 

 iron wire, which passes through the centre of the 

 coil, torsion of the wire induces currents in the coil 

 which are reversible with the direction of torsion, 

 but independent of its amount. A steel core does not 

 respond in this way to torsion : hence, by analogy of 

 the effects produced by inclining the core to the 

 plane of the coil, the lecturer argues a greater molec- 

 ular rigidity in steel than in iron. Attention was 

 called to the fact that the coercive power of iron is 

 greater than that of steel if the inducing forces are 

 ' within the range of iron.' Iron, on being twisted 

 or subjected to longitudinal vibration, lost its mag- 

 netism, steel did not. The magnetic properties of 

 iron were illustrated by a glass tube containing iron 

 filings, which lost its residual magnetism on being 

 shaken or carefully rotated. The greater molecular 

 rigidity of iron alloys was compared to the properties 

 of the tube when petroleum was poured in among 

 the iron filings, greater coercive power being thus 

 attained. These facts go to support the theory that 

 steel is an alloy of iron and carbon. — (Iron, Feb. 2.) 

 J. T. [483 



ENGINEERING. 



Stability of brick conduits. — Mr. A. Fteley 

 contrasted the theory on which the designing of brick 

 conduits is based with the actual conditions under 

 which such structures are built. Sewers aud con- 

 duits are often built in ground more or less yielding, 

 and the action of the earth about them is an im- 

 portant element of their stability. Under such con- 

 ditions, such structures must move more or less after 

 being built, aud the conditions of stability must be 

 very different from what they appear to be from 

 a study of the original drawing. A study of the 

 changes of form, by means of exact measurements 

 made during construction, might point to defects due 

 to the design or mode of construction, to tlie ground 

 in which the sewer or conduit is built, or to the want 

 of cai-e or skill in the builder. 



The author presented a diagram of an apparatus, 

 showing, in full size on a section drawn at a small 

 scale, all the deviations of the brick-work from the 

 true line of section. The exaggerated distortion of 

 the outline defines very clearly the slightest defects 

 in construction or the movement of the structure. 

 Diagrams were exhibited showing distortions in a 

 conduit nine feet in width and seven feet eight inches 

 high, and were taken at points where the conduit 

 was built in firm, dry ground, in yielding ground, 

 in wet trenches, on platforms in swampy land, and 

 on high artificial embankments. From these dia- 

 grams and the distortions they exhibited, the defects 

 in construction and design, in different locations and 

 under different loads, were explained. The tenden- 

 cies of the structure to spread iinder different con- 

 ditions was alluded to; also the section of excavation 

 in yielding ground best suited to prevent movement. 



An instance of the successful underpinning of a 

 brick conduit was described. A large quantity of 

 water broke in between the outside of the brick-work 

 and the sheet-piling supporting the trench, and washed 

 away the sand forming the foundation for a length of 

 about thirty feet, leaving it without support for that 

 distance. A very simple and efiicient means was de- 

 scribed by which this space was filled with a grout 

 of Portland cement. — (Bost. soc. civ. eng.; meeting 

 Feb. 21.) [484 



Steel castings. — M. A. Pourcel described recent- 

 ly, before the Iron and steel institute of Tienna, a 

 series of experiments upon steel castings. He stated 

 that the chief points to which attention is now di- 

 rected are, increase in the size of the castings, and 

 improvements in the methods of annealing and tem- 

 pering in order to endue the casting with the highest 

 mechanical qualities corresponding to the chemical 

 composition. The last progressive step was the cast- 

 ing of cylinders for a Paris firm, 2.04 m. in diameter, 

 over 2 m. long, and 55 mm. thick. These cylinders 

 supported a pressure of forty-five atmospheres with- 

 out showing signs of percolation. — (Engineering, 

 Dec. 8, 1882.) G. A. H. [485 



Screvsr-propeller blades. — The use of manga- 

 nese bronze as a material for screw-propeller blades 

 is rapidly extending. The first run of the ' Alaska ' 

 from Queenstown to New York in less than seven 

 days was made immediately after her steel blades had 

 been replaced by blades of manganese bronze. The 

 great qualities of manganese bronze are its strength, 

 and its freedom from corrosion. Recent experiments 

 show that it has a transverse strength about double 

 that of gun metal, and also, up to the elastic limit, 

 double that of steel. The cost of manganese bronze 

 is about double that of steel; but it is claimed that 

 propeller-blades made of the bronze will last during 

 the lifetime of the vessel, while steel blades require 

 renewal every three years. — (Engineering, Jan. 5.) 

 G. A. H. [486 



CHBMISTEY. 



{General, physical, and inorganic.) 



Formation of carbonic oxide. — Dr. L. P. Kin- 

 nicutt suggested a modification of Noack's method 

 (Berichte deutsch. chem. gessellseh., xvi. 75) for the 

 preparation of carbonic oxide. He found that this 

 gas was freely evolved when magnesia alba was heated 

 in a retort with zinc-dust, and that it contained a 

 small percentage of carbonic dioxide. — (Harvard 

 chem. cluh; meeting March 13.) [487 



On the probable existence of nevy acids 

 containing phosphorus. — Concerning the replace- 

 ment of oxygen by platinous chloride in certain 

 forms of phosphoric acid. Prof. W. Gibbs made the 

 following suggestions : " Schiitzenberger described, 

 some years since, a remarkable series of compounds 

 in which platinous chloride (PtClo) replaces a 

 molecule of chlorine or an atom of oxygen. Thus we 

 have PCI3 .PtCl., chemically equivalent to PCI5. 

 The corresponding acid is P . PtCL, . (OH);,, which 

 may be regarded as a derivative of PO (OH);,. The 

 same chemist obtained three other analogous acids, 

 having respectively the formulas P^ . PtCL^ . (0H)6 

 (corresponding to the chloride 2PC1 , . Pt CI.7), 

 P., . PtCl., . (OH),, and P.^ O, . PtCl . (OH);,. In 

 all these cases we have the chemical equivalence 

 PtCl.2 = 2C1 = O. Hence, following up the rela- 

 tion suggested by the equivalence expressed by 

 P . PtcT, . (0H)3 = P . O . (OH);,, it seems at least 

 probable that there are modifications of phosphoric 

 acid expressed by the structural formulas, — . 



