competition exists among the refiners, there is a strong inducement to
turn the heavier portions of the naphtha into the kerosene tank, so as
to get for it the price of kerosene. In this way the inflammable naphtha
or benzine is sometimes mixed with the kerosene, rendering the whole
highly dangerous. Dr. D. B. White, President of the Board of Health
of New Orleans, found that experimenting on oil which flashed at 113
degrees Fahrenheit, an addition of one per cent. of naphtha caused it to
flash at 103 degrees; two per cent. brought the flashing point down to
92 degrees, five per cent. to 83 degrees, ten per cent. to 59 degrees,
and twenty per cent. of naphtha added brought the flashing point down to
40 degrees Fahrenheit. After the addition of twenty per cent. of naphtha
the oil burned at 50 degrees Fahrenheit. There are two distinct tests
for oil, the flashing test and the burning test. The flashing test
determines the flashing point of the oil, or the lowest temperature at
which it gives off an inflammable vapor. This is the most important
test, as it is the inflammable vapor, evolved at atmospheric
temperatures, that causes most accidents. Moreover, an oil which has
a high flashing test is sure to have a high burning test, while the
reverse is not true. The burning test fixes the burning point of the
oil, or the lowest temperature at which it takes fire. The burning
point of an oil is from ten to fifty degrees Fahrenheit higher than the
flashing point. The two points are quite independent of each other; the
flashing point depends upon the amount of the most volatile constituents
present, such as naphtha, etc., while the burning point depends upon the
general character of the whole oil. One per cent. of naphtha will lower
the flashing point of an oil ten degrees without materially affecting
the burning test. The burning test does not determine the real safety
of the oil, that is, the absence of naphtha. The flashing test should,
therefore, be the only test, and the higher the flashing point the safer
the oil.