MAGNESIA AND MAGNESIUM. 281 



tals, which by a careful analysis I find composed 

 as follows : 



1 atom muriatic acid = 4'625 

 1 atom magnesia = 2-5 

 5 atoms water . = 5'625 



12-75 



If it could be rendered anhydrous without the 

 loss of its acid, it would doubtless be reduced 

 to chloride of magnesium, weighing only 6 

 grains ; but this cannot be done ; for when 

 the muriate is heated, not only the water, but a 

 considerable portion of the acid flies off and 

 leaves the magnesia. I may state an experi- 

 ment, however ; because it seems to show that a 

 chloride of magnesium might be formed, if the 

 requisite precautions were taken. It was the 

 only successful trial that I made, though my ex- 

 periments amounted to five or six. 15 '31 grains 

 of pure anhydrous carbonate of magnesia, equiva- 

 lent to 7'29 grains of magnesia, were dissolved 

 in muriatic acid, and the solution being evapo- 

 rated to dryness, the muriate of magnesia was ex- 

 posed to an incipient red heat, with every pre- 

 caution which I could devise to prevent the 

 escape of the muriatic acid. The salt thus treated 

 weighed 13*3 grains, and had a whitish'colour. 

 Water being poured upon it, the greater part 

 was dissolved with the evolution of much heat, 



