Chemistry and Physics. 69 



oxides of nitrogen ; the reaction beginning somewhat suddenly 

 and vigorously, about 180°-190° and being completed at 250° in 

 a proportionately shorter time. The evolved nitrogen oxides, by 

 mixture with air and conduction into water are re-converted into 

 nitric acid. But this regeneration is never complete ; even when 

 conducted at the ordinary temperature or in fact at a lower one. 

 Moreover, since there is also a loss of nitric acid during the evo- 

 lution of the chlorine — though in what form is doubtful, a portion 

 probably escaping as nitrosyl chloride — the authors conclude that 

 owing to this considerable loss of nitric acid, amounting at least 

 to 10 per cent and perhaps to 16 per cent of the acid used, the 

 chlorine method of Schlosing, commercially, has material disad- 

 vantages. — Ber. Berl. Chem. Ges., (Ref.) xxvi, 309, May, 1893. 



G. F. B. 



3. On Complex Acids containing Septivalent Iodine. — Blom- 

 straxd has described certain complex inorganic acids containing 

 the quinquivalent group 10 of periodic acid, analogous to the 

 trivalent group PO in phosphoric acid. These acids are classed 

 as monomolybdoperiodic acid IO(OH) 4 . O . Mo0 2 . OH, tetra- 

 molybdoperiodic acid . IO(OH) 3 (0 . Mo0 2 . O . Mo0 2 . OH) 2 and 

 hexamolybdoperiodic acid IO(OH) 2 (0 . Mo0 2 . O . Mo0 2 . OH) s . 

 The hexamolybdoperiodates were prepared by heating periodic 

 acid or the corresponding periodate with molybdic acid and the 

 carbonate of the same metal, in aqueous solution, until the whole 

 had dissolved, and then allowing crystallization to take place 

 spontaneously. In some cases a dilute solution of the acid itself 

 was prepared from a mixture of periodic acid and barium molybdate 

 by adding sulphuric acid, and this solution was then neutralized by 

 a metallic carbonate. The acid solution on evaporation yielded a 

 transparent amorphous mass with no trace of crystallization. 

 The sodium salt crystallizes with (H 2 0) 17 in rhombohedrons, and 

 with (H 2 0) 13 in triclinic prisms; the hydrogen potassium salt 

 crystallizes with (H 2 0) 12 in four or six sided triclinic plates; and 

 the lithium salt Li 5 Mo 6 I0 24 (H 2 0) 15 crystallizes in rhombohedrons. 

 The ammonium and the calcium salts, and also double salts of 

 strontium-sodium, barium-sodium and manganese-sodium are de- 

 scribed. By treating the ammonium salt of the hexa-acid with 

 ammonia, the tetramolybdoperioclate is obtained ; and by 

 treating the sodium salt similarly, ammonium-sodium mono- 

 molybdoperiodate is prepared crystallizing in quadrangular 

 triclinic plates containing four molecules of water. — Zeitschr. 

 anorg. Chem. i, 10 ; J. Chem. Soc, lxiv, (ii), 122, March, 1893. 



G. F. B. 



4. On the Refractive Indices of liquid Oxygen, Nitrogen 

 Monoxide and Ethylene • and on the Spectrum of liquid Oxygen. — 

 Liveing and Dewae have determined the constant of refraction 

 (/^ — l)/d for oxygen at its boiling point —182° and found it to 

 be 0"1989, it refraction-equivalent at this temperature being 3*182. 

 Using the formula (m 2 — 1)/(ju 8 +2)c7, the corresponding values are 

 0-1265 and 2-024. Liquid nitrogen monoxide at —90° gives for 



