White. — Marine Animal Oils 81 



of palmitic, together with some stearic and oleic acids. 

 This deposition of fat (roughly called "stearine" in the 

 trade, and used for soap-making) is of course markedly 

 hastened by cooling. It has been noted by the writer 

 that the liver oil of the smooth dogfish deposits much 

 larger amounts of "stearine" than does that of the spiny 

 dogfish. Torpedo liver oil gave none even after one hour's 

 standing over ice. 



The specific gravities of the various marine animal oils 

 and of linseed oil are very similar, averaging about 0.92 

 at 30° C. 



The viscosity, which is of great importance in consid- 

 ering the value of oils for paints and lubricants, varies 

 around the value 0.2 at 50° C. Viscosity values are 

 expressed in C. G. S. units. I have studied this phase 

 of the subject to a considerable extent and have devised 

 a viscometer requiring only five minutes for a determina- 

 tion and but five cubic centimeters for a sample of oil. 

 The accuracy of the instrument, method of manipulation, 

 and results are discussed in the original papers. 1 It was 

 found that the viscosity of the oils is very characteristic 

 and constant even if the different samples of oils were 

 obtained under diverse conditions. Mixtures of oils were 

 studied, and it was observed that the fluidities (fluidity 

 being the reciprocal of viscosity) of the mixtures are 

 strictly additive; that is, from the fluidity the percent- 

 age composition of the mixture can be calculated. It was 

 3tated that such a test of the character of an oil is not 

 Df great value if taken by itself, but is well worth con- 

 sideration along with other physical and chemical tests. 

 The fluidities of fish and vegetable oil mixtures were 

 also shown to be additive. 



Some marine animal oils have the property of drying 



:o a considerable degree, and this is a good reason for 



;he assumption that such oils contain large amounts of 



: insaturated fatty acid esters. The nature of these is not 



veil understood as it is extremely difficult to isolate such 



'Journal of Industrial and Engineering Chemistry, vol. 4, pp. 

 06 and 267 (1912). 



