82 WRITINGS OF JAMES SMITHSON. 



The means I have long employed to distinguish the two 

 sulphates apart was to fuse with carbonate of soda, wash, 

 dissolve in marine acid, &c.; but this process requires more 

 time and trouble than is always willingly bestowed, and 

 may even present difficulties to a person not familiarized 

 with manipulations on very small quantities. 



A few months ago a method occurred to me divested of 

 these objections. The mineral in fine powder is blended 

 with chloride of barium, and the mixture fused. The mass 

 is put into spirit of wine, whose flame is coloured red if 

 the mineral was sulphate of strontium. The red colour of 

 the flame is more apparent when the spirit is made to boil 

 while burning, by holding the platina spoon containing it 

 over the lamp. 



THE DISCOVERY OF ACIDS IN MINERAL 

 SUBSTANCES. 



From Thomson's Annals of Philosophy, Vol. XXI ; New Series, Yol. 

 V, 1823, page 384. 



April 12, 1823. 



SIR : Acids, it is well known, have been repeatedly over- 

 looked in mineral substances, and hence dubiousness still 

 hovers over the constitution of many, although they have 

 formed the subjects of analysis to some of the greatest 

 modern chemists. 



To be able to dissipate all doubts to ascertain with cer- 

 tainty whether an acid does or does not exist, and, if one is 

 present, its species, and this with such facility that the trial 

 may be indefinitely renewed at pleasure, and made by all, 

 so that none need believe but on the testimony of his own 

 experiments, is the degree of analytical power which it 

 would be desirable to possess. 



So far as I have gone in these respects, I here impart. 



