Chemistry and Physics. 373 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Separation of Titanium from Niobium, Tantalum, Tho- 

 rium, and Zirconium. — It has been found by J. H. Muller that 

 salicylic acid shows a different behavior with titanium hydroxide 

 than with the other " metallic acids." An excess of salicylic acid 

 added to alkaline niobate or tantalate solutions completely pre- 

 cipitates the acids, but the presence of an alkaline fluoride pre- 

 vents this precipitation. Orthotitanic acid dissolves in salicylic 

 acid, giving, in the absence of fluorides, an intensely yellow solu- 

 tion. Zirconium and thorium hydroxides dissolve with difficulty 

 in salicylic acid, but after ignition the resulting oxides are prac- 

 tically insoluble in it. 



Known amounts of the oxides of niobium, tantalum, zirconium 

 and thorium were each mixed with known weights of titanic 

 oxide, and the mixtures were then fused with 5 grams of potas- 

 sium carbonate, the fusions were taken up in 350-400 cc of water 

 at 60° and treated with 14-15 g. of salicylic acid, and heated for 

 3 or 4 hours at the boiling temperature. Then the precipitates 

 were allowed to settle, filtered rapidly, and washed with boiling 

 water. The concentrated filtrates were treated with ammonium 

 hydroxide, when titanium was precipitated, washed and ignited 

 to oxide. The precipitates were invariably contaminated with 

 alkali salicylates which could not be removed by washing. The 

 ignited oxides were, therefore, fused with potassium bisulphate and 

 weighed in the usual manner. 



The results given from test-analyses show remarkably good 

 results in the separation of elements which has heretofore been 

 exceedingly difficult or even impossible in some of the cases. 

 From the tabular statement of the results it appears that three 

 or four fusions are necessary with any but very small amounts of 

 titanic acid, although nothing is said about this point in the 

 description of the method. 



The exceedingly strong color of the salicylic acid solution of 

 titanic acid was used satisfactorily in determining the titanium in 

 several mixtures, but the author considers this calorimetric 

 method as of little practical value, owing to the interference of 

 the common contaminants of titanic oxide. — Jour. Amer. Chem. 

 Soc, xxxiii, 1506. h. l. w. 



2. Cementite. — This important constituent of steels, Fe 3 C, 

 which may be called also tri-ferro-carbide, has recently been care- 

 fully studied by Ruee and Gersten with interesting results. 

 The substance was prepared according to well known principles 

 by suddenly cooling molten iron saturated with carbon and treat- 

 ing the pulverized product at first for a long time with dilute 

 acetic acid, then pulverizing the residue and treating it further 



