TREES OF AMERICA. 141 



" Yes, sir ; for eating, and burning in lamps ; 

 and it is very good for curing burns and 

 scalds ; and for putting on hones to sharpen 

 knives and razors." 



" Very true ; but these are only some of its 

 uses. It is an indispensable article in the 

 preparation of a great many ointments and 

 other medicinal articles ; in the making and 

 polishing, as well as the sharpening, of all sorts 

 of edge tools ; it is used too for keeping steel, 

 and iron, and brass from becoming rusty ; in 

 softening horn and tortoise-shell fqr the manu- 

 facture of combs, &c. ; in the preparation of 

 leather ; and, in short, there is scarcely any 

 manufacture in which oil is not of great ser- 

 vice. But, after all. one of the most important 

 uses to which it is put, is in diminishing the 

 friction of all kinds of machinery. You know 

 how much more easily a wagon or carriage 

 will run when the wheels and axles are greased, 

 than when they are dry ; the grease or oil 

 makes the parts that touch slip smoothly over 

 each other ; and you can imagine of what 

 service this property is in the vast quantities 

 of machinery of all kinds that have been in- 

 vented, and are now used in the production 

 of almost every necessary as well as luxury 



