Probably the hour-glass is an invention of the first century after Christ. In the Middle Ages, a large number of inventions were spreaded out over a larger area by the opening of a commercial route between Europe, Arabia and China. The Chinese were far ahead of their time in technical respect and that is the reason why some sources said, that the hour-glass is a Chinese invention. Other sources mentioned: origin from Persia or Arabia.

On sailors, the hour-glass was used for measuring time. For example: who had to guard. One had to guard, for example, for four hours, which was also called: he has to guard for four hour-glasses. Smaller hour-glasses were used, for example, for measuring the speedness of a sailor. A wooden triangular instrument attached to a rope with knots, was thrown overboard by a sailor. Meanwhile another sailor, who was holding an hour-glass, which was indicating the half-minutes, was counting the number of knots, which was hanging over the railing. Then something or other was calculated in the speedness knots. People were also trying to appoint the duration of a sea voyage (also Columbus was doing this). However, during long voyages mistakes were inevitable, even when a punctual man was busy turning the hour-glass.

The hour-glass is also the symbol of transistory: Father Time with scythe and hour-glass. The hour-glass appears on graves, on "In Memoriam"cards, on medals, etc.

Nowadays, the hour-glass is being used for games or for boiling an egg and in the sauna. One still comes across hour-glasses as a souvenir. In advertising, the hour-glass is regularly being pictured.

My collection of hour-glasses:

On 1 January 2014 my collection consisted of 5700 pieces. Bigger, smaller and several different sizes and different time indicators. I'm in the possession of 2 hour-glasses, which both are doing exactly 24 hours and I also have an hour-glass which is only 11 mm. high and which is just doing 7 seconds.