John Fewster to save him from smallpox. According to Player Fewster replied that he had already thought of this but had decided against it as, in his view, variolation was very successful and an alternative seemed unnecessary. Nonetheless, Player reports, Fewster went on to inoculate three children in Thornbury with cowpox, during spring 1796. These vaccinations took place at around the same time as Jenner's first vaccination attempts. Fewster never made any claim to have discovered vaccination. John Fewster Dr John Fewster (1738–1824) was a surgeon and apothecary in Thornbury, Gloucestershire. Fewster, a friend and professional colleague of Edward Jenner, played an
Usable fuel Usable fuel In aviation, usable fuel is the fuel on board an aircraft that can actually be used by its engines. The opposite of usable fuel is unusable fuel. The unusable fuel figure is calculated for an aircraft fuel tank in "the most adverse fuel feed condition occurring under each intended operation and flight maneuver involving that tank". The figure usable fuel is used when calculating or defining other key figures of an aircraft such as MTOW, zero-fuel weight etc. Usable fuel is the total amount of fuel in an aircraft minus the fuel that cannot be fed into the