l5o ' Chemical Analjjls of Tin Ores. 



more foluble in the acid, for it is ftill found in the fame fiate 

 of faturation : befides, it does not exhibit anyfignsofthe 

 oxygenated muriatic acid gas ; and in this cafe it is difficult 

 to conceive why there (liould not rather be a difengagement 

 of this gas at the time of digcftion of the acid on the ore, as 

 happens with the oxydes of manganefe and lead. 



" To eftabhfh this point of theory on a decifive experi- 

 ment, I diflblved fix grammes of tin in nitrous acid, which 

 I evaporated feveral times to drynefs, adding each time frefh 

 acid. I think it cannot be doubted that in this ftate the tin 

 had taken all the oxygen it was capable of fixing; yet the 

 niafs of white oxyd, wafhed till the water that came from it 

 did not in the leaft alter vegetable colours, was readily dif- 

 folved in muriatic acid. What then is the caufe of the in- 

 foiubility of the ore, which alfo is nothing but tin and oxy- 

 gen, containing hardly O'Oi of extraneous matter ? The caufe 

 can only be found in the flate of aggregation of the latter. 

 This aflertion ought not to excite furprife, for hitherto fuffi- 

 cicnt account has not been taken of this power. If com- 

 binations are the refult of affinity or eleftive attraftion, this 

 attraction itfelf is nothing but a power which may be ren- 

 dered ineffectual by the fum of the forces which countera<St 

 it. Thefe truths furely will not be denied by Mr. Klap- 

 roth, who has rendered them fo palpable, by fhewing us that 

 the ruby, thefapphire, the adamantine fpar, the elements of 

 which were naturaHy eafily foluble, refiftcd the ordinary 

 means of analyfis only by the ftate of the aggregation of 

 their integral parts." 



De rifle, whofc fecond edition was publflied in 1783, con- 

 jeftured what Guyton here advances from experiment. His 

 words are as follow : — " I cannot agree with Mr. Bergman, $ 

 that there is no mineralizing fubftance in the cryftals of tin, 

 becaufe, in default of fulphur or arfenic, we ought at leaft to 

 find the acid principle, by the aid of which the metallic earth. 

 of tin takes a conftant and determinate cr^'ftalline form." 



VII. On 



