398 Scientific Intelligence. 



of the liquid. For phenol, at 46° to 78°, the value of E the molec- 

 ular surface energy, was found to be 736-9 and that of K 1*682 ; 

 whence M= 133-5. At 131° to 184°, these values were 490-6, 1-899 

 and 110-9 respectively; the value of K being less than 2-121 but 

 approaching it as the temperature rises. There is therefore in 

 this case some condensation on liquefaction ; or as the authors 

 call it, "association." In the case of bromine the value of M 

 obtained between 10-6° and 46° was 202-77 and between 46° and 

 78*1°, 184*59. It may be assumed that even in the liquid state, 

 therefore, most of the molecules have the formula Br 2 ; though 

 there is apparently some association with fall of temperature. 

 Nitric acid gave 105*9 for the value of M between 11*6° and 

 46-2°, and 117-4 between 46-2° and 78-2° ; showing that the 

 liquid acid is a mixture probably of HN0 3 and H 2 N 2 6 . Sul- 

 phuric acid, H„S0 4 is unstable and dissociates on warming into 

 S0 3 and an acid of the composition (H 2 S0 4 ) 12 H 2 approximately. 

 This acid gave a mean value for K of 0-209; indicating a molec- 

 ular mass corresponding to (H 2 S0 4 ) 32 . Phosphorus between 78-3° 

 and 132-1° gave a value of 2*205 for K, corresponding to a 

 molecular mass of 117 ; or practically P 4 . Hence it appears (l) 

 that phenol like the alcohols forms complex molecules in the 

 liquid state, which dissociate as the temperature rises; (2) that 

 bromine also is somewhat associated but on rise of temperature 

 gives simpler grouj)ings of Br 2 ; (3) that nitric acid consists 

 largely of molecular groups (H1SI0 3 ) 3 ; (4) that sulphuric acid is a 

 very complex substance at ordinary temperature its complexity 

 being probably not lower than (H 2 S0 4 ) 32 , a rapid diminution 

 taking place above 132°; and (5) that phosphorus in the liquid 

 state has a molecular mass the same as that of its gas P 4 . — Jour. 

 Chem. Soc, lxiii, 1089, Sept. 1893 ; lxv, 167, March, 1894. 



G. F. B. 



3. On the Manufacture of Oxygen from Calcium Plumbate. — 

 It had been observed by Le Chatelier, on investigating the disso- 

 ciation of calcium plumbate, that in order to evolve the oxygen 

 by heat alone, it was necessary to raise the temperature about 

 200° higher than was required by barium peroxide; but that, on 

 the other hand, the oxygen is more rapidly and completely re- 

 absorbed from the air at lower temperatures by the plumbate 

 than by the peroxide. Kassner has now called attention to the 

 fact that while the oxygen can be obtained from the plumbate by 

 heat alone other methods are more advantageous. He especially 

 recommends the following : Porous calcium plumbate is mois- 

 tened with steam and subjected to the action of washed furnace 

 gases preferably at a temperature below 100°. The carbon di- 

 oxide in these gases is rapidly absorbed, the material then con- 

 sisting of a mixtui*e of calcium carbonate and lead peroxide. 

 This is transferred to a retort kept constantly at a red heat and 

 in this the oxygen is evolved, the evolution being much helped 

 by the introduction of a current of steam. After the oxygen is 

 evolved, the current of steam is continued, and the temperature 



