Chemistry and Physics. 14/7 



point determinations. When the boiling point is reached vapor 

 escapes from the capillary tube, and this may rise through the 

 liquid of the bath as bubbles or be absorbed by it according to 

 circumstances of solubility. In determining the boiling point 

 the temperature is raised somewhat above the required tem- 

 perature, then by cooling the point is found where the bubbles 

 cease to be given off, or the liquid recedes in the capillary tube. 

 For taking vapor pressures the apparatus is modified so that the 

 heating is carried out in a test-tube containing some of the liquid 

 used as a bath, and this in turn is placed in a beaker containing 

 the same liquid. The test tube is closed with a stopper through 

 which passes the thermometer as well as a glass tube connecting 

 with a manometer and also with suction or compression appa- 

 ratus. With this arrangement boiling points may be taken at 

 various pressures, and of course these give the vapor pressures. 



The quantity of substance required for these determinations is 

 only about O'l g, and it is important to notice that the boiling 

 points of solids which do not melt, as well as liquids, may be 

 taken in this way. The liquids recommended for use as a bath 

 are, besides water, sulphuric acid of 92 - 75 per cent, paraffine of 

 M. P. 53°, a two nitrate mixture with KN0 3 and NaN0 3 in the 

 proportion 54-55 to 44-5, and a three nitrate mixture with NaN0 3 : 

 KN0 3 :LiN0 3 :: 18-18 : 54-54 : 2V'2T. A correction for the pres- 

 sure of the liquid of the bath above the opening of the capillary 

 tube is required, and tables are given showing the specific gravi- 

 ties of the different liquids mentioned above at various tempera- 

 tures. The authors give very satisfactory results of determina- 

 tions made by the new method, and it is their opinion that the 

 boiling points thus determined are more accurate than by the old 

 methods, because there can be no difference in the temperature of 

 the liquid, the vapor and the thermometer. — Jour. Arner. Chern. 

 Soc, xxxii, 897. h. l. w. 



3. The Reactions of Nascent Hydrogen in the Dry Condition. 

 — Vournassos has found that the nascent hydrogen produced by 

 heating dry sodium formate is capable of combining with various 

 simple substances which do not combine with hydrogen directly, 

 but which form hydrogen compounds indirectly. Thus by heat- 

 ing sodium formate with phosphorus, or with sodium phosphites 

 or phosphates, PH 3 is obtained; likewise H 2 S is obtained by 

 heating the formate with sulphur, sodium sulphite, or a sulphide 

 of mercury, lead or tin. With arsenic AsH 3 is produced. Anti- 

 mony gives a little SbII 3 . Silicon does not react, but SiCl 4 and 

 SiS 2 give a little SiH 4 . B 2 3 heated with metallic sodium and 

 the formate gives a gas which appears to be BH 3 . The nitrides 

 give NH 3 , the cyanides HCN, and the alkaline carbides C 2 H 2 . — 

 Comptes JRendus, cl, 464. h. 1,. w. 



4. Synthetic Sapphire. — Verneuil has obtained artificial sap- 

 phires by fusing before the oxyhydrogen blowpipe alumina 

 mixed with 1-5 per cent of magnetic oxide of iron and 0-005 per 

 cent of titanium dioxide. The ovoid masses obtained gave a 



