Sterile water was provided to each culture by capillary action from a 500 ml vacuum flask.
The capacity of the vacuum flask industry is being substantially increased and several new firms are entering it.
Suppose a driver took a vacuum flask to enable him to have a hot meal during the journey.
He dealt with certain kinds of thermos flasks, and instances could be given of other types of vacuum flask, showing the game that has been played.
I confess that it is conceivable but not particularly likely that it may contain a soft drink instead, in which case it is no worse than a vacuum flask.
A typical domestic vacuum flask will keep liquid cool for about 24 hours and warm for up to 8.
The insulation of the vacuum flask results in a very slow boil and thus the contents remain liquid for long periods without refrigeration equipment.
An early 1919 high-altitude oxygen system used a vacuum flask of liquid oxygen to supply two people for one hour at.