From these it is evident that the duration of the becalming effect will
vary with different oils, and therefore further experiments upon these
difference should be made, in order to select that kind which is the
most effective, with due regard, of course, to cost.
The oil indicated by my experiments as combining permanency and
cheapness, and altogether the most suitable and attainable is the
“_dead oil_” refuse of the gas-works. This may be used in its crude and
cheapest condition.