APPENDIX. 



Analysis of the Oils produced by certain Indian Rays and other 



Aquatic Vertebrates. 



By D. Hooper, F.C.S., Industrial Section, Indian Museum. 



Among the specimens of fish captured by the ' ' Golden Crown ' ' and handed over 

 to tlie Indian Museum for determination have been several species which yield large 

 quantities of oil. The collection and use of marine animal oils in some parts of the 

 world constitute important industries, but in India these fats are very rarely utilised, 

 and their chemical composition and properties have never been studied. Whale and 

 seal oils are occasionally imported for leather dressing and other purposes, and it does 

 not appear that any serious attempt has been made to exploit the oils of Indian fish. 



The first oil examined was that of the Gangetic Dolphin {Platanista gangetica). 

 This animal is called susu, sehu and sisar , and the oil is locally used as an embrocation 

 for rheumatism and as an illuminating agent. The oil is yellowish-brown becoming 

 reddish-brown on keeping, has a faint fishy smell, and deposits no solid fats at the 

 winter temperature of Calcutta (i8 — 22° C). 



The following constants were obtained : — 



Specific gravity at 15° C. 



Acid value 



Saponification value 



Iodine value 



Reichert-Meissl value 



Fatty acids, per cent. 



Melting point of .. .. .. iS.S" C. 



x\cid value of 

 Iodine value of 



Although it is allied to the sperm whale, the oil of this animal contained no sperm- 

 aceti. There is a fair amount of free fatty acids, but there is only a small proportion 

 of the more volatile fatty acids. The .solid fatty acid, calculated as palmitic acid, 

 amounted to about 16 per cent. Such an oil would be of value for currying purposes, 

 for burning and for lubricating fine machinery. The other oils examined were those 

 of the hvers of certain large fish brought from the Bay of Bengal, and identified b}- 

 Dr. Annandale. The livers were from the following species : — 



1. White ^ting-^ay {Trygon micyops). 



2. Common Saw-Fish (Pnstis perottetii). 



3. Spotted Shark (Stegostoma tigvinum). 



4. Shark Ray (Rhainp/inbntis ancylosloDiits). 



