Miscellanies. 383 
and let one of the mean proportionals more one of the lines, be 
squared, and the square of said proportional subtracted therefrom, 
the residue is to equal the square of one of the first given lines 
geometrically. 
42. Chromate of iron was discovered by the late Gen. Martin 
Field, in Townsend, Vt.—Letter to the Editor from Dr. Jacob 
Porter dated Plainfield, Mass. March 14th, 1835. 
Extracted by O. P. Hubbard. 
CHEMISTRY. 
1. Phloridzin, a new substance.—Messrs. Koninck & Stay an- 
nounce their discovery of a new organic substance in the bark of the 
crab-tree, the wild pear, plum and cherry trees, which they name 
Phloridzin, and of which they will soon publish a complete account. 
—L/ Institute, Mars, 1835. 
2. Preparation and analysis of some essential oils, by M. R. 
Blanchet.— Oil of Roses. 0.508 parts of a sample of oil of roses, 
which presented all the properties of the true essence of Persia, hav- 
ing been burned with oxide of copper, gave 1.380 of carbonic acid, 
and 0.555 of water, or in 100 parts, 75.11 carbon, 12.13 hydrogen, 
and 12.76 oxygen, a result very remarkably different from those ob- 
tained by Saussure and Goebel. Alcohol separates this oil ito por- 
tions very nearly equal, of stearoptine and eleoptine.—Stearoptine of 
Oil of Roses. The process by which this is prepared, is founded 
upon its different solubility in alcohol and ether. Mix oil of roses 
with 3 parts of alcohol at 33° B., and dissolve in ether the stearop- 
tine which is deposited, and remove by repeated washings the eleop- 
tine which still adheres to it. Ata temperature of + 25° C. it 
_ presents the appearance of crystallization like butter ; is melted at 
+35° C., and boils without alteration between 280° and 300° C., 
giving out the odor of boiling fat oil. Ata very elevated tempera- 
ture it burns like olefiant gas with a clear flame and no soot. 0.338 
of this substance burned with the oxide of copper produced 1.005 
carbonic acid and 0.438 water. It consists therefore of 
i By experiment. By calculation. Atoms. 
Carbon 85.86 85.98 1 
Hydrogen 14.46 14.02 2 
