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Oils of Southern India, [no. 5, new series, 



allowing the mucilage to subside ; for this reason, old oil is prefer- 

 able to new for lamps. The manufacture of oil gas for illumi- 

 nating purposes must not be passed over in silence. Oil dropped 

 on a red hot surface is instantly converted into gas, (oil gas) and 

 with the aid of very simple machinery, can be made by the most 

 inexperienced person. It was at one time made to some extent in 

 England, but the high cost of the oil and other causes, led to its 

 abandonment in favor of coal gas. 



Oil, — as a lubricating agent. — Any of the fluid non-drying oils, 

 may be used as lubricants for machinery. For fine work, the Ben 

 oil (Hyperanthera moringa) being free from any disposition to ran- 

 cidity, is to be preferred, but for Railway carriages, a more 

 solid substance, such as Piney tallow or Gamboge butter is 

 more suitable. At present, however, a composition prepared by 

 agitating lamp oil with nitric acid, for which the maker holds a pa- 

 tent, is employed successfully. The Gamboge butter, has been re- 

 ported on favorably, by the Railway agent, as " very clear and free 

 from grit, and suitable for lubricating axles." A more extended 

 experiment with this substance is in contemplation. A locomotive 

 engine is said to consume between eighty and one hundred gallons 

 annually. A mixture of grease and tar is used for Native carts. 



Oil— for anointing the person. — As an application for rendering 

 the skin supple, which in tropical climates, is an almost indispen- 

 sible necessary of life, any of the greasy oils will answer. Those 

 generally preferred by the natives are Cocoanut, Gingeley, and 

 Mustard oils. The former has been sometimes used by the Euro- 

 pean perfumer in the manufacture of scented oils for the hair, but 

 the difficulty of preventing its acquiring the well known disagreea- 

 ble odour, or of disguising it with the most powerful scents, is the 

 chief objection to its use. The Moringa or Ben oil, from the great 

 length of time, it keeps without acquiring rancidity, is well suited 

 to the perfumer's use. 



Oils — as articles of food. Oil is largely used as an article of 

 food in all tropical countries, and as the qualities of most edible oils 

 are well known, little need be added on this head further than to 

 recommend greater cleanliness in the expression, and a more profita- 

 ble use of the oil cake ; which, however, valuable as a manure is 



