16 BULLETIN %9, U. S. DEPARTMENT OF AGRICULTURE. 
substitute made from fresh herring oil is already on the market in 
the West Coast States. 
OLIVE OIL. 
DOMESTIC SUPPLY. 
Replies to a questionnaire sent to a majority of the olive pressers 
of this country by the Bureau of the Census, in June, 1917, indicate 
that in 1916 we made some 1 ,300,000 pounds of olive oil. A later 
request mailed to all oil producers by the Food Administration 
brings this figure up to 1,461,000 pounds. This is only about 2 per 
cent of our consumption of olive oil, and less than 0.1 per cent of our 
total domestic production of vegetable oils, during the period. In 
1917 our production apparently decreased to a little over 963,000 
pounds. The United States imports, largely from Italy, France, 
and Spain, about 50,000,000 pounds of edible and 5,000,000 pounds 
of inedible olive oil annually. The exact amounts, taken from the 
reports of the Bureau of Foreign and Domestic Commerce, are given 
in Table 4. 
PRESSING OLIVES. 
Olive oil is probably the most widely known of the virgin oils. 
It is obtained by grinding nearly ripe olives, usually pits and all, in 
a suitable mill, and pressing the resulting pulp in large fruit presses 
very similar to those used in making cider or grape juice. To press 
the pulp it is wrapped in a coarse cloth to form so-called "cheeses,' 7 
which are then stacked in piles, each cheese being separated from 
the one above by a lattice grating of wooden slats, and pressure ap- 
plied. As the pressure applied to the olives is comparatively light, 
the oil obtained need only be washed and filtered to yield the pure 
virgin oil of commerce. The pomace left from the first pressing is 
reground, and, after the addition of a little hot water, again pressed 
to form lower grades of olive oil. Finally, a very low grade of oil 
may be obtained from the last cake by extraction with some vola- 
tile solvent, such as ordinary gasoline, or, abroad, carbon bisulphid, 
the solvent, of course, being later boiled off from the oil. 
CAN WE INCREASE OUR PRODUCTION? 
Most of the American olives are grown for pickling, and, as none 
of the oil is lost in the processing and canning of the ripe or green 
olives, there would be no real gain in using more of the olive* crop for 
oil and less for pickling. At the present time probably nearly all 
of the cull olives fit for making oil are being utilized in this way, 
since the price of olive oil is so high that it pays the grower to ship 
culls to the oil mills, which formerly would not bear the freight 
charges. As an olive tree does not yield fruit in commercial quanti- 
ties until it is 5 years old, there is no possibility of an immediate 
