If the residual pressure in a cylinder presented for filling does not produce a reasonably strong flow of gas from the valve when opened the filler may refuse to fill the cylinder unless an acceptable reason is given for it being empty, as there is no way for the filler to check if it has been contaminated.
12.
Though modern epigrams are usually thought of as very short, Greek literary epigram was not always as short as later examples, and the divide between " epigram " and " elegy " is sometimes indistinct ( they share a characteristic metre, elegiac couplets ); all the same, the origin of the genre in inscription exerted a residual pressure to keep things concise.
