The Rotatory Power of Limonene at Low Temperatures

F. A. Molby
1910 Physical Review  
T HE work described in this paper is a continuation of the study of the effect of low temperatures upon the optically active substances, the first results having been published in the January number of the PHYSICAL REVIEW of the present year. The former paper contained a description of the apparatus used in the study of quartz. The apparatus used in the study of limonene is essentially the same, namely, a Lippich triple field polariscope of most recent and improved construction (Schmidt &
more » ... on (Schmidt & Haensch), graduated in circular degrees and hundredths of a degree, and an iron-constantan thermo-couple, with potentiometer, for measuring temperatures. The range of temperature through which the limonene has been studied is from 20 0 to -130 0 . For the most part the observations end at -120 0 . The limonene studied was procured through the Fritzsche Brothers of New York. It was ordered especially for this work and bears Schimmel and Company's (of Leipsig, Germany) mark " limonene pure." Occasion is here taken to thank the firm for furnishing the special order free of charge. The sample was secured from the manufacturers in July, 1908, and the package was kept unopened until March of this year. It is hoped that by keeping it thus and by using much care to prevent contamination and to prevent oxidation by exposure to the air, the results will be faultless so far as the purity of the specimen can enter into them. As considerable difficulty was encountered in obtaining a satisfactory tube for observations, due to the very great solvent power of the liquid on all rubber washers or organic seals tried for making joints, the tube used will be described here with a view of a
doi:10.1103/physrevseriesi.30.77 fatcat:qmgtelqlebbo3ojrlw25dulpoy