306 MINERALOGY. 



Yttria enters into the composition of the Gadolinite ; a 

 Mineral only found at Ytterby, in Sweden. 



8. Barytes. This, which has frequently been considered 



as an Alkaline earth, is when pure, white, ponderous, 

 and has a sharp acrid taste, and is a Tiolent poison. 



Barytes has never been met with pure, is not abun- 

 dant, and only enters into the composition of two or thiee 

 earthy substances ; these are thQ Witlierite, Heavy Spar, 

 and Hepatite : all natives of this country. 



9. Strontian. Like the last this Mineral has a consider- 



able affinity to the Alkalies ; when pure it is white, and 

 its taste and properties resemble those of Barytes. 



This earth is of rare occurrence, and is only known com- 

 bined with one or two earthy substances, never having beea^ 

 found pure. 



ALKALINE MINERALS. 



These are found combined with earthy substances and 

 Acids, but do not enter into the composition of Metals. The 

 taste of all the Alkalies is acrid and nauseous, nearly 

 resembling Barytes, and Strontian ; with which they also 

 further agree in their chemical properties. Alkali is an 

 Arabic word, applied to the residium of a plant called Kali, 

 which is burnt for the purpose of obtaining the Saline ashes, 

 with Avhich it abounds ; some Alkalies are termed fixed, in 

 contra-distinction to such as are volatile. 



