378 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE 



IJ Chemistry akd Physics. 



1. Hydrated Oxalic Acid as an Oxidimetric Standard. — 

 Arthur E. Hill and Thomas M. Smith have rendered a 

 valuable service to the art of volumetric analysis by devising a 

 method whereby crystallized oxalic acid H 2 C 2 4 .2H 2 can be 

 prepared in a state of purity in regard to its contents of water, 

 so that it contains no excess of moisture derived from the mother- 

 liquor, nor any deficiency of water due to efflorescence. The 

 principle of the method is very simple and depends upon expos- 

 ing the moist acid to an atmosphere in equilibrium at all ordinary 

 temperatures with the pure hydrated acid. Such an atmosphere 

 is obtained in the presence of mixtures of the hydrated and anhy- 

 drous acid obtained by heating the crystallized acid in a porce- 

 lain dish upon the steam-bath for a few hours. When a large 

 excess of this mixture is placed in a desiccator with the moist acid 

 the moisture of the latter is lost, but none of the water of crystal- 

 lization can go off on account of the presence of the hydrated acid 

 in the mixture which establishes the proper tension of aqueous 

 vapor to prevent this change, since the system becomes univariant 

 according to the phase rule of Gibbs. The authors have found 

 it necessary to powder the crystallized acid sufficiently to pass a 

 100-mesh sieve in order to expose the mother-liquor included in 

 the crystals to the process of drying. The time necessary for 

 drying in a desiccator under these conditions is about two days, 

 but the time may be shortened to about one hour by the use of 

 a current of air which is first bubbled through a saturated solu- 

 tion of the acid and then is passed through U-tubes containing 

 the desiccating agent and through a closed jar containing the 

 substance. 



The results given by the authors show that the acid prepared 

 in this way gives results that are reliable within very small limits 

 of error when used with potassium permanganate, and it appears 

 probable that it might be used very satisfactorily for standard- 

 izing solutions of strong alkalies by the use of phenolphthalein 

 in boiling solutions. — Jour. Amer. Chem. Soc, 44, 546. 



h. l. w. 



2. The Atomic Weight of Beryllium (Glucinum). — Honig- 

 schmid and Birkenbach have made a new determination of this 

 atomic weight, apparently with great care and- skill and with 

 satisfactorily agreeing results by the analysis of the anhydrous 

 chloride. They started with the commercial carbonate and puri- 

 fied the material, particularly by crystallizing and afterwards 

 volatilizing' the basic acetate. The latter was converted into 



