Chemistry and Physics. 637 



S C I E N T I F I C INTELLIGENCE. 



I. Chemistry and Physics. 



1. A New Colorimetric Method for Titanium. — Lenher and 

 Crawford have applied thymol in concentrated sulphuric acid 

 to the determination of titanium. The reddish yellow to red 

 color is proportional to the amount of titanium present. As 

 thymol itself gives a color when dissolved directly in sulphuric 

 acid, it should be first dissolved in a little acetic acid, and then 

 concentrated sulphuric should be added. The ratio of thymol to 

 titanium may vary greatly, but it has been found best to have at 

 least -006 g. of thymol present to every -0001 g. of Ti0 2 . The 

 test should be made in the presence of strong sulphuric acid, for 

 when the strength of this acid is below 79*4 per cent the color 

 fades in a regular manner with the dilution. The color should 

 be observed at room temperature, for it becomes paler with rise 

 in temperature. Fluorine has a bleaching effect upon the color, 

 but hydrochloric acid, phosphoric acid, and tin did not show any 

 effect. Tungstic acid, on the other hand, increases the color in 

 direct proportion to the amount of tungsten present. The tita- 

 nium-bearing material is usually most conveniently brought into 

 solution by fusing with potassium acid sulphate. The fusion is 

 taken up in concentrated sulphuric acid, thymol in sulphuric 

 acid is added, and after diluting with sulphuric acid to a definite 

 volume the color is compared in a colorimeter with a standard 

 titanium solution. The test-analyses given by the authors show 

 excellent results, and the method appears to be rapid and conven- 

 ient. — Eighth Internat. Congress of App. Chern., vol. i, p. 285. 



h. l. w. 



2. The Determination of Carbon by Combustion in Moist 

 Oxygen. — S. Hilpert calls attention to the fact that, while it has 

 been known for a long time that the presence of moisture facil- 

 itates combustion, the presence of this agent is purposely avoided 

 in analytical operations. He has found that certain carbides of 

 magnesium and manganese were only slightly oxidized when 

 heated for a long time at a bright red heat in dry oxygen, but 

 the combustion was easily completed when the oxygen was passed 

 through a wash-bottle containing water before it entered the com- 

 bustion tube. The presence of moisture did not interfere with 

 the determination of carbon, as a good calcium chloride tube was 

 placed in front of the potash apparatus. He has found this 

 method applicable to the direct combustion in oxygen of iron and 

 steel alloys, where the combustion goes on much faster and at a 

 lower temperature with moist than with dry oxygen. Also in 

 elementary organic analysis it has been found that difficultly 

 combustible substances may be much more easily burnt in moist 

 oxygen. In cases where hydrogen is to be determined as well as 



