4 THE ROYAL SOCIETY OF CANADA 



intervals. The di-ester crystallized out first the monoester followed, 

 and a mass amounting to 10-15% of the fusion, of almost noncrystal- 

 line very soluble substance always remained. By repeated separation 

 into fractions as well as combining those fractions having similar 

 melting points, the mono-and di-esters were separated and purified 

 to constant melting point. 



In all the experiments the yield of the diesters was, even with 

 the excess of glycol, many times greater than the monoester. 



The solubilities of the esters in absolute alcohol (at 15-5° C. 

 sp. gr. 0-79451 =99-86%) at varying temperatures were carefully 

 determined. The alcohol was saturated at a few degrees above that 

 at which the observation was to be made and kept at the temperature 

 of observation for from 5-6 hours; about 10 c.c. of the clear superna- 

 tant solution were drawn off by a warm pipette into a stoppered 

 weighing bottle, weighed, the alcohol evaporated and the residual ester 

 dried to constant weight. The results are stated in grammes of acid 

 dissolved in 100 grammes of alcohol. All determinations were made in 

 duplicate and gave concordant results. 



The indices of refraction were conveniently and accurately de- 

 termined by means of a Zeiss Refractometer, at a temperature only a 

 few degrees above the melting point. 



The specific gravities of the fused esters were determined at tem- 

 peratures near their melting points. The determinations were 

 made in a bulb tube of about 3 c.c. capacity on a capillary stem 

 carefully calibrated. The observations were made on the tube sus- 

 pended with a small accurate thermometer in the inner narrow 

 chamber of a double walled glass vessel. The outer chamber was 

 connected with a reflux condenser and in it was boiled some liquid 

 such as — chloroform, methyl or ethyl alcohol, whose vapor gave 

 the desired temperature. The results were recorded when the 

 temperature and the readings on the capillary stem of the tube re- 

 mained constant for 20-30 min. 



Glycol Di-stearate [C2H4(Ci8H3502)2] so prepared is a pure 

 white solid, crystallizing from alcohol in beautiful pearly plates, or 

 occasionally from ether in needles forming a paper-like mass on the 

 filter. It melts at 75° C. sharply (Wiirtz gives 76° C.) and the liquid 

 has a refractive index of 1-4385 at the melting point. The specific 

 gravity of the fused fat at 78° C is 0-8581. It is quite soluble 

 in warm ether, fairly so in cold ether and very slightly soluble in 

 alcohol, it crystallizes out almost completely at room temperature 

 from hot absolute alcohol. 



