ON THE FORMATION OF MINERALS. 203 
spread of cholera are supported by facts here: all the outbreaks of cholera 
have been preceded by a murrain in cattle. (Diet No. 11.) 
106. J. J. Herrernan, Thyet-Myo, states that the daily dietary of the free 
population contains rice 1 to 1} Ib., dal 2 to 3 ozs., fish or flesh 2 to 4 ozs., 
vegetables 4 to 5 ozs., oil 1 oz. (seldom used), gnapé (nearly always used in- 
stead of salt), and condiments. The Burmese, except those addicted to the 
use of intoxicating liquors and drugs, enjoy average health. 
Synthetical Researches on the Formation of Minerals, &c. 
By M. Aurnonse Gaces. 
Sixce my last Report my experiments have been chiefly directed to the 
synthesis of serpentine and some other magnesian minerals,—to the action of 
animal organic matter in the production of minerals (a subject which has 
been often discussed, but is always worth being more fully studied from an 
experimental point of view),—and lastly, to the action which solutions con- 
taining the materials of felspar may have had in altering the composition 
and structure of Cambrian and other ancient rocks. The results which I 
propose to give here must necessarily be fragmentary, both from the nature 
of the investigation itself, and the fact of its being still in progress. 
My first object has been to ascertain the kind of action which alkaline solu- 
tions exert on the hydrated silicates, of magnesia, iron, and lime, and to 
endeavour to determine synthetically the formation of serpentine and some 
other rocks allied to it. 
The composition of the mineral known as serpentine is almost constant, 
while the rock known by that name, though essentially agreeing in composi- 
tion with the mineral, contains nevertheless various foreign matters. The 
circumstances under which serpentine-rocks are found and their general 
character indicate that they are not generally derived from the gradual alter- 
ation of a preexisting rock, but have been produced by the direct deposition 
of silicates which accidentally enclosed foreign substances, and which by 
dialysis lost alkalies, and by subsequent infiltration may have gained some 
other constituents and led to the formation of other minerals in the mass. 
The process I have employed to arrive at the synthesis of serpentine is 
based on the solubility of the hydrated silicate of magnesia (2Mg0O,3S8i0, +4HO) 
im alkalies, and on the precipitation which results when a diluted solution of 
bicarbonate of magnesia is added. 
1st Experiment.—A given quantity of silicate of magnesia in the gelati- 
nous state was introduced into a muslin bag and held in suspension in a 
diluted solution of caustic potash. After some days the silicate enclosed in 
the bag was found entirely dissolved. This solution, left in repose in a glass 
cylinder for some months, deposited a transparent colloid, which, after being 
Washed and dried, presented the following composition :— 
Geltga 2), SOR gehts 50:036 
MGeTOSIA | oc. vt ie 19-419 
POPERE ase cents 17:642 
Water... wivigecumnenind 12-980 
100:077 
