Intelligence and Miscellaneous Articles. 229 



ON THE PRESENCE OF BORACIC ACID IN THE THERMAL WATERS 

 CONTAINING ALKALINE SULPHURETS AT d'oLETTE (EASTERN 

 PYRENEES). BY JULES BONIS. 



The progress of analytical chemistry is continually making known 

 to us the presence of substances in the water of springs, which may 

 to a certain extent account for their effects either in agriculture or 

 therapeutics. During the last few years a number of very important 

 investigations have been made upon this subject, and it is only by 

 means of the consideration of a great number of experiments and 

 well-established facts that we have arrived at a knowledge of the 

 true nature and mode of formation of mineral waters. 



H. Rose has recently proposed a method for detecting the pre- 

 sence of very minute quantities of free or combined boracic acid in 

 solution, by taking advantage of the reaction which it gives with 

 turmeric paper. 



The analogy which exists in certain respects between the waters 

 of the Pyrenees and those of Tuscany induced me to seek for boracic 

 acid in the former, and I selected the waters of Olette as being the 

 type of sulphuretted waters discharged at the earth's surface with a 

 high temperature. These waters issue from a quartzose and fel- 

 spathic rock, which is decomposed under their influence, giving rise 

 to products which I shall bring before the Academy upon a subse- 

 quent occasion. 



In order to detect the presence of boracic acid in a mineral water, 

 I evaporate a certain quantity in a porcelain capsule and acidulate 

 the residue with hydrochloric acid, when if boracic acid is present 

 it communicates to turmeric paper the characteristic red colour. 

 Generally speaking, the simple coloration is not sufficient evidence 

 of its presence ; and notwithstanding the opinion of H. Rose, so 

 competent and always so conscientious an authority on subjects con- 

 nected wdth analysis, I was desirous of convincing myself of the effi- 

 cacy of this reagent by repeated trials. I first ascertained that water 

 containing carbonates of potash and soda did not, when evaporated 

 in a porcelain capsule, give the least red colour with turmeric paper, 

 after the addition of hydrochloric acid ; I have obtained the same 

 result with silicate of potash, sulphate of soda, sulphuret of sodium, 

 and chloride of sodium. Finally, I made an artificial water having 

 the same composition as that in which I suspected the presence of 

 boracic acid ; and on operating with it in precisely the same manner 

 as with the natural water, obtained a negative result. 



For the purpose of bringing out the colour in a marked manner, I 

 dip the paper into the liquid to be tested, previously acidulated ; I 

 then dry it and repeat this operation several times, at last pouring 

 over the paper some water faintly acidulated with hydrochloric acid, 

 which deepens the colour. Characters drawn with acidulated water 

 upon the paper thus prepared become perfectly legible. 



The sensibility of this test is such that I was enabled to detect 

 the presence of boracic acid in the waters of Olette by evaporating 

 500 cubic centimetres in a platinum capsule ; and to judge from the 

 colour communicated to the paper, I should say that the quantity of 

 borjite is considerable. As to the possibility of extracting this acid 



