THE COLLOID-CHEMISTRY OF SOAP MANUFACTURE 169 



of the glycerids of the different fatty acids are as indicated in the 

 following table, copied from LEWKOWITSCH. 



*SPALLANZANI: Le Staz. Sperim. Hal., S3, 417 (1890). 



Beeswax consists chiefly of free cerotic acid with a small 

 quantity of free mellisic acid and small quantities of unsaturated 

 fatty acids combined with alcohols. CV.ryl alcohol appear- 

 in IHH'SWUX. Beeswax contains little or no glycerin, other alcohols 

 taking its place. 



3. Significance of Some Fat and Oil Constants for the 

 Colloid- Chemistry of Soap 



Since complete analyses of the fats and oils which enter the 

 soap chemist's kettle can scarcely be obtained, he must content 

 him-elf in routine practice with a knowledge of their specific 

 gravity, melting point, saponifi cation value, I\in mur-M M->I. 

 value, iodin number, etc. For the non-technically trained, the 

 meaning of these values and their probable significance indeter- 

 iniiiiiig in advance the colloid properties of the resultant soaps 

 when more complete analyses of the fat are miing are appended. 



Since the natural oils and fats are not definite chemical sub- 

 stances characteri/ed by definite melting points, it become< 

 readily intelligible why disrordant results an- obtained by any 

 of the number of methods available for the determination of I he 

 meltirm point- of oik ;md Fall, In ueneral. however, it max Ke 

 -aid that the lower the meltiim point of :i fat or oil, the higher 

 the proportion in it of the lower melting point fatty acids, like 

 the oleates. linolates or lower member^ of the Mtic Wriflf. 



The vjMM-itir of any pun- fat fall- in any series with 



rise of the fatty acid in that series. Wide differences, however, 

 between the specific gravities of the fatty acids of dili 



I? i- ditlieiilt for this reason, to find an\ ivlat ionshij) 



