Elements of chemistry, in two volumes / by John Murray.

  • Murray, John
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

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    it lias been proposed to transfer them to this class, lhey are still, however, on the whole, more strictly connected with the other earths : and if the entire series is to be sub- divided into orders, it could not be done with more pro- priety, than into the three which have been stated. The alkalis may be regarded as associated and distinguished from the others by their much greater solubility in water, and affinity for it; by their solubility in alcohol; by theii greater fusibility and volatility, and in general by theii greater activity as chemical agents. Some newly discovered substances, it has been stated, have been added to this class. Of these, one, Lithina, is found to exist in certain minerals, and is hence properly associated with the others, potash and soda, which also occur in a number of minerals. There are others, as Morphia or Morphine, Cinchonine, &c. which are exclu- great specific gravity. But in the other mode of placing the al- kalis and earths, as metallic oxides, this prominent distinction is lost, potassium and sodium being lighter than water, and the other metalloids little heavier; and the anomaly is thus presented, of classing these with platina and gold, which are more than twenty times heavier. Another inconvenience attending the common ar- rangement regards one of the alkalis, ammonia, which in alkaline qualities is not inferior to either of the others, and is indeed closely related to them in all its agencies, yet not having a metallic base, is not associated with them, but in most chemical works occu- pies a singular situation, being placed beside olefiant gas, phos- phuretted and sulphuretted hydrogen, and other compounds of hy- drogen, to none of which certainly does it bear the smallest re- semblance. In Dr Murray’s arrangement alone is it placed in a situation corresponding to its characters. For these, and other rea- sons which might be stated, Dr Murray’s arrangement has always appeared to me preferable to every other, and I have accordingly strictly followed it in the text. Ed.
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