PETROL 



293 



B 



C 



SOLID 



Paraffin, C 27 H 56 , melting about 60 

 C H 66 



55 V ^30 62 " 55 ^^ 



etc. etc. 



The first and most important use alike of the crude natural 

 petroleum and of portions separated by distillation is for burn- 

 ing as a source of heat or power. 



The fluid residue from the refineries has for many years been 

 employed under the name ostatki, as fuel on the locomotives in 

 Southern Russia, and on the steamers on the Black Sea and 

 Caspian. The use of liquid fuel has many obvious advantages 

 coupled with some disadvantages. First of all it is composed 

 almost entirely of the combustible elements carbon and hydrogen, 

 while bituminous coal contains not only oxygen, but a con- 

 siderable quantity of mineral matter which is left in the form of 

 ash or clinker after burning. 



A further advantage possessed by a liquid is that it occupies 

 much less space than an equal weight of a solid in lumps, and 

 may be stowed in bunkers of any shape or in spaces which could 

 not be utilised for coal. The bunkers can also be filled by simple 

 pumping with the expenditure of much less labour, the flame 



