250 On the Composition of Arragonite. [Oct. 



III. 



On Strontia.71 as a Constituent of Arragon. By the Academician 



Gehlen.* 



{In a Letter to the Editor, dated March 4, 1814.) 



According to your wish, I communicate to you, for insertion in 

 your Journal, my experiments on Stromeytr's discovery of strontian 

 in arragonite; and 1 do it the more readily, because there is some 

 difficulty in bringing this constituent into view. 



Professor Stromeyer's discovery became known to me at Land- 

 shut. The effect which it produced on Professor Fuchs and me 

 induced us to undertake a set of experiments in order to assure 

 oursehes of the accuracy of the statement. 



But though we followed the mode pointed out hy Mr. Stromeyer, 

 we were not able to obtain any satisfactory results respecting the 

 strontian. We digested alcohol of about 90° upon the dry solution 

 both of Spanish and French arragonite. There remained no pon- 

 derable residuum, though the experiment had been made on 200 

 grains of arragonite. A trace of undissolved matter remained, 

 which was not taken up hy water. Both solutions were gently 

 evaporated to the consistence of a syrup, and set aside in that state ; 

 but no crystals of nitrate of stiontian made their appearance in the 

 course of a week, as we had expected them to do. 



Another method was now attempted ; namely, the evaporation of 

 a solution of arragonite in nitric acid previously mixed with a certain 

 proportion of solution of gypsum. It was expected that a double 

 decomposition would take place, and that the strontian would in 

 this manner be separated from the great proportion of lime with 

 which it was mixed, and might in consequence be subjected to 

 farther examination. A previous experiment with a solution of 192 

 grains of carbonate of lime mixed with eight grains of carbonate of 

 strontian verified this expected conclusion. This solution being 

 mixed with the solution of gypsum, and evaporated to the consist- 

 ence of a syrup, let fall fine soft needles. These being separated 

 by the filter, and washed with weak alcohol, coloured the flame of 

 the blow-pipe purple red (as is the case wth sulphate of strontian). 

 It was now treated with an alkaline carbonate, and the residuum, 

 being washed, was dissolved in muriatic acid. The solution crys- 

 tallized in fine needles, soluble in alcohol, and giving that liquid 

 the property of burning with a purple colour, and thereby showing 

 decisively that it was strontian. 



But a similar experiment made with a solution of arragonite was 

 not equally successful ; for the portion that separated was not of 

 such a nature that it could be readily recognised. My departure 

 for Vienna prevented the farther prosecution of these experiments. 



• Schweigger's Neues Journal fiir Chomie und Physik, x. 133. 1814, 





