The report describes the development of techniques for the preparation of emulsions of No 2 fuel oil and water. The resulting emulsions are suitable for firing in the experimental rig being used by the National Air Pollution Control Administration to investigate factors influencing emissions from domestic oil-heating equipment. The wide range of available emulsifying agents was screened to a workable number by using the hydrophilic-lipophilic balance (HLB) concept. A blend of two commercially available emulsifying agents was identified as satisfactory for preparing water-in-oil emulsions that contained up to 53 percent water and were stable over a 10-week period. Atomization of the emulsions by a high-pressure nozzle produced sprays having droplet size distributions similar to those for No. 2 fuel oil. Emulsions containing 5, 10, 19, 29, and 53 percent water were fired successfully in a conventional gun-type burner without modification. (Author)