April 27, 1883.] 



SCIENCE. 



341 



their true value, as two elements of the deflective 

 force are omitted (Science, p. 98); but this does not 

 affect the author's conclusions, as the deflective force 

 is still insignificant, and, for a fast train in this 

 latitude, amounts to but about 3-0'cru of the weight. 



— W. M. D. [700 



The type of modern marine engines. — Con- 

 structing-engineer Albrecht, of the Austrian navy, 

 discusses the various forms of engines and boilers 

 which have been proposed or used, gives data and 

 indicator-diagrams for various ships, shows that the 

 compound engine effects a saving of fifty-seven per 

 cent over the simple, and pronounces the three- 

 cylinder compound engine the most economical and 

 best. — [Mitth. gebiete seew.jS..^.) c. E. M. [701 



Torpedo-nets. — Lieut. Sleeman, K.N., proposes 

 to render torpedo-nettings useless as a protection for 

 ships by sending one Lay torpedo after another, in 

 the same path, at short intervals. The first breaches 

 the net; the second passes the breach, and explodes 

 against the ship. — {Journ. de la flotte, Feb. 18. ) 



C. B. M. . [702 



Pendulum-chronograph. — Capt. Caspersen, of 

 the Danish army, has devised a chronograph for 

 ballistic purposes, which consists of a pendulum pro- 

 longed above its point of suspension so that it can 

 be arrested at its extremities at will by levers con- 

 nected with electro-magnets. A horizontal wire is 

 fastened at the point of suspension, with its ends 

 bent so as to dip in cups of mercury; and thus, 

 when tlie pendulum is oscillating, the contact is 

 made alternately on the two sides, and registered 

 automatically on a dial. The instrument measures 

 with precision the hundredth of a second. — (Mitth. 

 gebiete seeio., x. 9.) 6. e. m. [703 



CHEMISTRY. 

 ( GeneraU physical, and inorganic.) 



Conduct of moist phosphorus and air to- 

 wards carbonic oxide. — In repeating the experi- 

 ments of Leeds and of Baumann, Prof. Ira Eemsen 

 and E. H. Kaiser observed a copious precijMtate on 

 passing the mixed gases through barium hydrate. 

 When, however, all contact of the gases with corks 

 and connectors was prevented, there was noformation 

 of barium carbonate. — (Amer. chem. journ., iv. 454.) 



C. F. M. [704 



White phosphorus. — A modification of phos- 

 phorus, quite different in its properties from the 

 variety hitherto known as white phosphorus, was 

 obtained by Eemsen and Kaiser in the distillation of 

 ordinary stick phosphorus. The distillation was 

 conducted in an atmosphere of hydrogen, and the 

 distillate collected in a receiver partly filled with 

 water and ice. At the end of the distillation a thin 

 white cake was found floating on the surface of the 

 water. It dissolved readily in carbonic disulphide, 

 melted at the same temperature as the common form, 

 and, on melting, was transformed into the latter. 

 It withstood the action of sunlight longer than ordi- 

 nary phosphorus. — {Amer. chem. journ., iv. 459.) 



0. F. M. [705 



Specific heat and valence of thorium. — On 



further study of the metal thorium, L. F. Nillson 

 finds that it is tetratomic, and that its atomic heat 

 calculated from the mean of several determinations 

 of the specific heat 0.027S7 is 6.4. Analogous to sili- 

 con, it forms a fusible alloy with platinum ; and the 

 composition of its chlorplatinate corresponds to those 

 of tin and zirconium. — (Bericlite deutscli. chem. 

 gesellsch., xvi. 15'3.} c. F. M. [706 



Formation of arsenides by pressure. — When a 



mixture of zinc filings and arsenic in powder was sub- 

 jected to a pressure of 6,500 atmospheres, W. Spring 

 observed the formation of an arsenide (ZniiAs.^). 

 Corresponding arsenides of lead (PbnAsj), cadmium 

 (Cd3As2), and of copper (CU3AS2), were also pre- 

 pared. Varying the proportions of copper, CugASa 

 and CuijAsi were formed. Tin gave SU3AS4, and 

 silver Ag;jAs and Ag,iAs, the latter a brittle mass 

 of metallic lustre and gray color. — {Berichte deutsch. 

 c/iem. lyeseHsc/i., xvi. 324. ) c. r. m. [707 



Production of apatites and -wagnerites con- 

 taining calcium bromide. — When sodium bromide 

 is heated to a temperature just above fusion, and cal- 

 cium phosphate is added to it, A. Ditte states that well- 

 developed hexagonal pyramids separate on cooling, 

 which have the composition CaBrj . 3 (CasiPOj)^). 

 On heating calcium bromide and calcium phosphate 

 together, a compound (CaBr^ . Ca^ (P Ot}-,) corre- 

 sponding to wagnerite crystallizes in long needles. If 

 calcium arseniate is used, instead of the phosphate, in 

 the preceding experiments, in the first case the com- 

 pound CaBrj . 3(Ca;,(As04).2) crystallizes in hex- 

 agonal pyramids, and, in the second case, CaBro . 

 Ca:, (As04).2 is formed. When vanadic acid is fused 

 with sodium bromide and calcium bromide, the chief 

 product is a bromo-vanadate, CaBrj . 3(Ca:i( ^'04)2). 

 The corresponding wagnerite (CaBrj . Ca (V04)2) 

 results when the acid is fused with pure calcium 

 bromide. Analogous compounds may be formed in 

 which calcium is replaced by other metallic elements. 

 — (Comptes rendus, xcvi. 575.) c. F. M. [708 



The atomic •osreight of lanthanum. — Since the 

 iatomic weight of lanthanum was reduced by the re- 

 sults of Brauner to 138.28 from 139.15, the value for- 

 merly obtained by Cleve, the latter sought to verify 

 or disprove Brauner's result by a more careful prepa- 

 ration of the material from which the atomic weight 

 was determined. From 1.5 kilos, of the mixed 

 oxides of cerium, thorium, lanthanum, and didym- 

 ium, the first two elements were removed by treat- 

 ing the partially decomposed nitrates with water, and 

 didymium by fractional precipitation with ammoni- 

 um hydrate. The seventh fraction was converted 

 into the sulphate, and submitted to fractional crystal- 

 lization. The last mother-liquor contained 10 grms. 

 of the sulphate, which, on analysis, gave 138.69 as the 

 atomic weight. Since a trace of didymium could 

 still be detected by the spectroscope, the fractional 

 crystallization was continued until analysis showed 

 a constant percentage of lanthanum. The mean of 

 several determinations gave 138.22 as the atomic 

 weight. Cieve seeks to explain the difference be- 

 tween his results and those of Brauner by the dif- 

 ferent methods employed to obtain pure material. 

 He thinks, that, since Brauner depended upon a frac- 

 tional crystallization of the oxalates, his product may 

 have contained a trace of yttrium. — {Bidl. soc. chim., 

 xxxix. 151.) c. F. M. [709 



, METALLURGY. 



Silver-milling at Charleston, Arizona. — Ac- 

 cording to Mr. W. Lawrence Austin, the ore, as the 

 mine was developed, gradually changed, and was 

 found to carry wulfenite (molybdate of lead). The 

 bullion resulting from milling this changed ore ran 

 down to from 200 to 300 fine. The fineness was again 

 restored to 970 by stamping much finer, and giving 

 up altogether the grinding in the pans; departing 

 from the usual custom of stamping, 35 mesh to the 

 inch, and grinding, and also by the use of lime in 

 cleaning the amalgam. Cerussite and galenite did 

 not cause the same trouble as wulfenite. — (Enc/. 

 min. journ., Jan. 27.) B. H. B. [710 



