A CHEMICAL STUDY OF DOLOMITES. 
NICHOLAS KNIGHT 
Deodat Dolomieu was born in Dolomieu, France, June 23, 1750, 
and died November 16, 1801. In infancy he was created a Knight 
of Malta and seemed precocious in many directions. When nine- 
teen years of age he quarreled with a companion and killed him. 
He was condemned to die for his crime, but after nine months' 
imprisonment, he was pardoned on account of his youth. He 
early became interested in geology and mineralogy, and wrote 
some important treatises on his favorite subjects, especially while 
residing in Metz, the interesting old capital of Lorraine. 
He discovered dolomite while making an extended tour and 
observations among the Alps in 1789-90. The mineral was first 
described by him in 1791, and the name was bestowed upon it in 
honor of the discoverer. 
The dolomite mineral and rock are important and interesting 
from both a theoretical and practical standpoint. Much work has 
been done upon them, and the mineral can be artificially produced 
by a number of different methods. 
Marignac was probably the first to make it synthetically. His 
method was to heat calcium carbonate and a solution of magne- 
sium chloride to 200° under a pressure of fifteen atmospheres. In a 
closed gun barrel J. Dorocher heated porous limestone and dry mag- 
nesium chloride to about 1200°. The vapor of the chloride perme- 
ated the porous limestone, which was partly transformed into dolo- 
mite. In a similar way, it has been suggested, the heat in the 
neighborhood of volcanoes may produce the mineral and rock. 
One of the simplest methods was devised by C. Sainte-Claire 
Deville. He saturated chalk with a solution of magnesium chlor- 
ide and heated the mixture upon a sand-bath. More or less of 
the materials changed into dolomite. 
By heating powdered calcite with magnesium sulphate to 200° 
in a closed tube von Morlot obtained a mixture of dolomite and 
calcium sulphate. It has been suggested by Haidinger that this 
reaction accounts for the frequent association of dolomite and 
gypsum. 
T. Sterry Hunt conducted a long series of experiments on the 
