2-'!-' Scientific Intelligence. 



mighl be manufactured by igniting the magnesium chloride in 

 the presence of steam. — lour. Indus/. Engr. Chem., 10, 96. 



H. L. W. 



'2. Potash from Cement Mills. — Much attention has been paid 

 recently to the dust from cement kilns as a source of potash, 

 both under the usual conditions and with the suggestion thai 

 material such as feldspar richer in potash than that ordinarily 

 employed, should be used in the operation. 



Albert R. Merz, of the TJ. S. Bureau of Soils, states thai dust 

 precipitated by the Cottrell process at a works in California 

 where oil was used' for fuel in the kilns, had 92 per cent of its 

 potash in a water-soluble condition, while at two Eastern works 

 where powdered coal was blown in as the fuel only 60 and 42 

 per cent of the potash could be dissolved in water. Merz appears 

 to have found a remedy for this serious difficulty, as he found 

 that when the Eastern dusts were heated at temperatures of 

 from 600 to 1100° for a short time the greater part of the potash 

 became soluble in water, apparently on account of the action of 

 the lime present in the dust upon insoluble silicates. 



Another aspect of this matter has been presented by N. S. Por- 

 ter, Jr., and R. D. Ciieesman, of a Portland Cement Company 

 in Michigan. They have found that the content of potash in 

 coal ashes is considerable, amounting in several cases to about 

 5 per cent, and since it appears that most of this ash, under the 

 conditions employed, passes into the dust, they believe that this 

 is the chief source of the insoluble potash. They do not believe, 

 as Merz has suggested, that the coal ash combines with the vola- 

 tilized potash from the change and renders it insoluble. They 

 make no suggestion as to a remedy for the difficulty, such as 

 plowing in a little dry slacked lime with the coal, but it is to be 

 hoped that the method of Merz or some other device will make 

 this source of potash available. — Jour. Indust. Eng. Chem., 

 10, 109. h. l. w. 



3. The Preparation of Very Dilate Permanganate Solutions. 

 — J. O. Halverson and Olaf Bergeim have found that particular 

 precautions are necessary in the preparation of these solutions 

 where the strength is about 1/100 normal. They state that 

 when such solutions are made up by diluting stronger ones, as 

 is frequently done, there is enough organic matter in the dis- 

 tilled water used for dilution to seriously affect the strength, 

 even if the diluted solutions are used almost immediately. Even 

 when the water used for diluting had been distilled from both 

 acid and alkaline permanganate, there was still a serious dete- 

 rioration of the solutions. They recommend, therefore, the 

 dissolving of 0-40 g of pure potassium permanganate crystals in 

 a liter of redistilled water, in a very carefully cleaned flask, then 

 digesting the solution for 36 hours at near the boiling point, 

 cooling, allowing to stand over night, and without disturbing the 



