26 



SCIENCE 



[N. S. Vol. L. No. 1279 



platmum ware containing 2.4 per cent, iridium. 

 Palau and rhotanium " C " behave towards reag- 

 ents in about tlie same way as rliotanium " A, " 

 except that they are not suitable for potassium 

 pyrosulphate fusions and are inferior to grade 

 "A" for sodium hydroxide fusions. The only 

 striking distinction between rhotanium "C" and 

 palau is the latter 's slight superiority in the case 

 of the pO'tassium pyrosulphate fusions. Palau and 

 both grades of rhotanium may all be used to ad- 

 vantage in the electrolysis of chemical solutions, 

 but only as cathodes. As anodes the alloys are 

 worthless. It is believed that in order that the above 

 tests may indicate the true merit of the alloys, in- 

 formation should be available as to the behavior of 

 these wares in actual laboratory service. Unfor- 

 tunately the authors have very little of such in- 

 formation at their disposal, and suggest that any 

 further available information of this nature, both 

 favorable and unfavorable, be communicated to 

 the Bureau of Standards. 



Hydrogen overvoltage; applications to reduc- 

 tion, metal corrosion and deposition (lantern) : D. 

 A. MacInnes and A. W. Contieri. Maclnnes and 

 Adler have advanced a theory in which hydrogen 

 overvoltage is related to the surface energy neces- 

 sary to form the evolved bubbles. The theory re- 

 quires that the overvoltage increase with a de- 

 crease of the external pressure, and vice versa, a 

 prediction verified in some unpublished work by 

 Goodwin and Wilson. In this paper it is shown 

 that, in aoid solutions, reduction by metals is ac- 

 celerated, corrosion of metals is decreased, and 

 the electrolytic deposition of metals is made more 

 efficient, by reducing the external pressure. 



The ternary system CaO-MgO-SiO„ (lantern) : 

 John B. Ferguson and H. E. Merwin. A brief 

 discussion of the experimental methods, followed 

 by a general survey of the liquidus-soUdus rela- 

 tions. Several new compounds will be described; 

 the solid solutions of different types which occur 

 will be touched upon and the effect of solid solu- 

 tions upon inversion temperature will be men- 

 tioned. 



The influence of chemical composition on the 

 birefringence in strained glass (lantern) : Erskine 

 D. Williamson. All glasses to be used for optical 

 instruments must be tested for the presence of 

 internal strains. The only convenient method of 

 accomplishing this is to measure birefringence as 

 observed between crossed nicols. It is therefore 

 necessary to know how the observed birefringence 

 for a given amount of strain depends upon the 

 composition of the glass which is being used. Fig- 



ures are presented for the eight types of optical 

 glass made by the Pittsburgh Plate Glass Com- 

 pany during the war. 



The determination of oxygen by the copper-am- 

 monia-ammonium chloride reagent: W. L. Badger. 



Fluidity and hydration (lantern) : Eugene C. 

 Bingham. 



The preparation of cyanogen chloride: W. L. 

 Jennings and W. B. Scott. Nearly quantitative 

 yields (98 per cent.) of cyanogen chloride may be 

 obtained conveniently by passing chlorine into 

 finely powdered sodium cyanide, containing 2 per 

 cent, of water, suspended in carbon tetrachloride 

 and kept cooled to — 3° C. At the end of ithe 

 operation the product is distilled off and by re- 

 distillation over mercury is obtained pure. This 

 method appears to be an improvement on the 

 earlier methods in which mercuric cyanide was 

 used as initial material, and on the later methods 

 in which chlorine was passed into aqueous solu- 

 tions of hydrocyanic acid or alkaline cyanides. 



Electrolytic preparation of permanganates: 

 Charles Heckek. 



A study of the constant-ioiling mixture of hy- 

 drochloric acid and water : Marion Hollingsworth. 



A holder for spools of iron wire for standardisa- 

 tion: Marion Hollingsworth. The holder is 

 made from sheet metal and carries the spool sup- 

 ported in a stoppered bottle. The construction is 

 such that the wire may be conveniently drawn out 

 as desired without exposing that which is left to 

 the corroding atmosphere of the laboratory. 



A new buret support: Marion Hollingsworth. 

 This support is designed to carry a buret attached 

 to a supply bottle. It has the advantage that the 

 buret's height may be varied without any of the 

 graduations being obscured. 



Charles L. Parsons, 

 Secretary 

 {To be concluded) 



SCIENCE 



A Weekly Journal devoted to the AdvEincement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SCIENCE PRESS 



LANCASTER. PA. GARRISON, N. Y. 



NEW YORK. N. Y. 



Entered in the post-office at Laocastcr. Pa., aa secoDd class matter 



