AQUATIC PRODUCTS IN AKTS AND INDUSTRIES. 235 



certain grades of cod oil, but at present these refer, respectively, to 

 B and C grades of pressed menhaden oil, gradiial increase in adul- 

 teration having resulted in complete change of material. 



The principal uses for menhaden oil are currying or filling leather, 

 illuminating, j)aint-making, lubricating comi)Ounds, tempering, soap- 

 making, screw-cutting, wire-drawing, and cordage-manufacture, the 

 first three consuming about 80 per cent of the total product. The 

 light and extra light oils are generally employed in illuminating, 

 lubricating, painting, and cordage-manufacture; the light brown for 

 currying, and the dark oil for tempering and screw-cutting. 



Large quantities of menhaden oil were formerly used by miners in 

 safety lamps, but leather-currying has been the principal consumer 

 during the last thirty years. Its use in steel works is of compara- 

 tively recent origin, and the steel industries now require many 

 tliousands of barrels annually. 



It was as a substitute for linseed oil in painting that menhaden 

 acquired its first popularity prior to 1865.' The oil as then prepared 

 was of very indifferent quality, the process of manufacture being com- 

 paratively crude, and much of the product would not now be consid- 

 ered marketable. On account of its being too highly recommended 

 and all grades being sold for the purpose, considerable prejudice was 

 soon created against it as a substitute for linseed oil. But with 

 the improved methods of extraction and refining and with a better 

 understanding of its limitations and technical qualities, these objec- 

 tions have been largely overcome. Its odor makes it undesirable for 

 interiors and restricts its use to outside surfaces. According to Mr. 

 A. H. Gill, its value for drying is somewhat less than that of linseed, 

 but greater than that of poppy-seed, corn, cotton-seed, and sesame oils. 



Menhaden stands the weather much better than linseed oil, espe- 

 cially when applied to tin roofs and ironwork. Owing to its glutinous 

 nature, it is harder to apply than linseed oil, and consequently work- 

 men do not always favor its adoption. This use of menhaden oil is 

 now increasing and a single paint factory in New York City consumes 

 4:,000 or 5,000 barrels annually. 



If the oil is cleared from the foots by straining or pressing, cut with 

 sulphuric acid of 45° strength in proportion of 1 gallon of acid to 50 

 gallons of oil, well stirred in and permitted to settle, and then washed 

 down by a spray of cold water played on it, the acid and gluten are 

 precipitated. Thus treated, menhaden makes a good substitute for 

 linseed oil in mixing i^aints; it may also be used for leather-dressing 

 and, mixed in equal proiDortions with paraffin and plumbago, makes 

 a desirable lubricator. 



The use of menhaden oil for illuminating purposes is confined to 

 miners' lamps, especially in the coal mines of Pennsylvania and West 

 Virginia. For this purpose it is generally combined with mineral or 

 vegetable oils, the mixture giving better satisfaction than the use of 

 menhaden oil alone. It is non-explosive and therefore much safer 



