TRANSACflONS OF THE SECTIONS. 51 



' As the presence of zinc was the source of very great injury to the iron-master, not 

 only in consequence of its forming incrustations, but also on account of a certain 

 quantity of it finding its way into the cast iron and thereby rendering it very brittle, 

 1 was requested by the proprietor of these furnaces to examine the various mate- 

 rials that were employed, and try to find out in which of them existed the compound 

 of zinc which gave rise to these several incrustations. 



Having failed to discover any blende or calamine in the limestone used, I next 

 examined the iron ores, and found that the ' under penny-stone ' (a name given ia 

 Shropshire to the ironstone nodules which are employed there nearly exclusively) con- 

 tained small black crystals, which proved, on analysis, to be sulplmret of zinc or blende. 



Since this observation was made by me, E. W. Binney, Esq., F.R.S., has placed a 

 very interesting paper in my hands (published in 1852), in which he describes the 

 presence of the sulphurets of lead and zinc " as existing in the druses or hollows of 

 ironstone nodules occurring in coal-measures, which seem to indicate that metals 

 had in some instances been precipitated from aqueous solutions, or segregated from 

 semifluid masses." 



But it would appear probable, from the recent researches of Messrs. Fremy, 

 Deville, and Senarmont, that the blende has formed itself in the druses by the action 

 of a volatile sulphuret on the oxide of zinc which had been deposited in those druses 

 after they had been formed in the ironstone. 



In examining the coals employed, I found in the lowest strata which bear the name 

 of "Court Bandies Coal" in the neighbourhood of Coalbrook Dale, a large quantity 

 of white metallic scales disseminated through the mass of coals, exactly in the same 

 manner as pyrites are observed in the same substance. The presence of such scales 

 having not yet been observed, I analysed them, and found them to be composed of 

 galena mixed with a little blende. 



I think that the pi'esence of the blende and galena in the iron mineral and in the 

 coals, clearly indicates that in the neiglibourhood there must be veins or lodes of the 

 sulphurets of these two metals. 



On the Salts actually present in the Cheltenham and other Mineral Waters. 

 By J. H. Gladstone, Ph.D., F.R.S. 



The Cheltenham waters have been analysed by many distinguished chemists, and 

 the experiments of Messrs. Abel and Rowney leave nothing to be desired in point of 

 accuracy, that is to say, as far as the amounts of chlorine, carbonic acid, soda, lime, 

 &c. are concerned ; but the author contended that the usual method of arranging the 

 results of analysis, as so much chloride of sodium, so much carbonate of lime, &c., 

 was utterly fallacious. The rule of ' combining the strongest base with the strongest 

 acid ' is purely empirical, and almost incapable of application, since our knowledge is 

 very vague as to which is stronger and which weaker ; but the rule is also false, if it 

 be true, as the author has found it to be wherever proof was possible, that " where 

 two or more binary compounds are mixed under such circumstances that all the 

 resulting bodies are free to act and react, each electro-positive element arranges itself 

 in combination with each electro-negative element in certain constant proportions." 



The method of determining the salts actually present in a water by evaporating it 

 down and exhausting the residue successively with aether, alcohol and water, is also 

 fallacious, for the state of combination of the acids and bases may materially alter 

 when crystallization is taking place. 



The paper of Messrs. Abel and Rowney contains indications that the salts are not 

 actually present in the Cheltenham waters in the manner in which they are arranged 

 in their lists of analyses. Thus so carefully had these chemists experimented, that 

 they observed there was not sufficient free carbonic acid to retain in solution the lime 

 and magnesia which, according to the usual principles, they supposed present in the 

 form of carbonates. Hence they imagined them dissolved by the alkaline salts, and 

 add, " We have satisfied ourselves by direct experiment, that the solubility of car- 

 bonate of lime is much increased by the presence of chloride of sodium and sulphate 

 of soda." Now all this is the necessary consequence of the law of reciprocal aflinity, 

 as the lime, instead of monopolizing the carbonic acid, will unite more or less with the 

 other acids present, forming salts soluble in water. 



The author was fully aware that analytical chemists themselves did not profess the 



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