50 BULLETIN 2, XT. S. DEPARTMENT OF AGRICULTURE. 
recommended especially for replacing linseed oil in the manufacture 
of patent leather and similar products and printing ink. The patent 
leather resulting is more flexible and less liable to crack, though it 
possesses a somewhat less glossy surface. An objection to its use 
in this manner, however, is a peculiar efflorescence which its presence 
causes to form on the surface of the preparation. Its moderate use 
in the manufacture of baked japans also has been found highly 
advantageous. 
Menhaden oil should, of course, be used with a drier, and for that purpose 
the best results are obtained by means of a tungate drier. A tungate drier is 
one in which tung oil, or China wood oil, is boiled with a lead aiud manganese 
oxide, and when the solution is complete this is then mixed with a properly 
made resinate of lead and manganese. Such a drier becomes soluble in the 
oil at temperatures over 100° C, and hardens the resulting paint very 
thoroughly. For fabrics, however, fish oil must be heated to a temperature of 
over 200° C, and if air is injected at such a temperature the glycerides are 
expelled and thick oil is produced which, in conjunction with the drier just 
named, is equally good for printing inks. It is advisable, however, to add at 
least 25 per cent of either a heavy bodied linseed oil or a raw linseed oil which 
does not break before the manipulation just referred to is begun. 1 
The manipulation requisite on the part of the manufacturers to 
render their oils immediately usable for paint vehicles involves 
merely the addition of the drier and boiled linseed oil to the fish 
oil. The product should be sold directly to the paint manufacturers. 
The advantages gained are a higher price gotten because of this 
manipulation and because of the elimination of the middleman, and 
the assurance which the paint manufacturer has that the oil pur- 
chased directly from the manufacturer of fish oils probably is the 
pure product. 
In this connection it should be added that undoubtedly there are 
certain other ways, and probably many more, in which the value 
of the menhaden oil easily might be enhanced. The considerable 
portion of the time when, because the fish-rendering plant is lying 
idle, the employees are unoccupied, should make it possible for the 
operators to expend more labor on their oil with a view to the im- 
provement of its quality, and to manipulate it to render it suitable 
for special purposes, without greatly adding to the cost of manu- 
facture. 
1 Toch, loe cit. 
| ADDITIONAL COPIES of this publication 
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