It is known as clock to the device that makes it possible to specify a time measurement, segmenting it into different units. Sand, for its part, is the name given to the accumulation of particles from rocks and gathered on the shore of a river or an ocean.
A Hourglass it’s a instrument that appeals to the sand to allow the temporal measurement. These clocks measure specific lapses of weather which are initiated when the sand located in the upper vial begins to fall into the lower vial through the force of gravity and that they end when all of the sand has already passed into this second blister.
In the 8th century it seems that it was when the idea and the reality of the hourglass first appeared in Europe, since it is believed that it was a monk named Liutprando who presented it to make use of it in the Cathedral of Chartres, in France.
However, it would not be until the fourteenth century when it became popular and it was already common to use it in many different areas. A good example of this is that it appears represented in various paintings of that time, as would be the case of the painting “Allegory of Good Government” (1338) by Ambrogio Lorenzetti.
The operation of the hourglass is very simple. It is a transparent glass or plastic instrument, with two identical-size ampoules or bulbs that communicate through a small hole in the center of the device. Inside, enough sand is placed to fill half or slightly more than the capacity of a blister. By the action of the gravity, the sand always accumulates in the vial at the bottom: when someone takes the watch and turns it over, the lower vial becomes the upper one and the sand starts to fall through the hole, passing to the blister that was now below.
The hourglass thus measures a period of Fixed time (how long it takes for the sand to pass from one blister to the other). This period can be equivalent to one minute, for example. If what you want is to measure the exact time that elapses between two events or to know the time, the hourglass is of no use.
For a long time, the hourglass became a fundamental piece in many boats, because it helped them to carry out with great precision what were measurements that the sailors had to undertake such as the distance to the west or the east as well as even the length. In this way, they chose to make use of the aforementioned instrument instead of others that they had been using up to that moment and that were much less precise. We are referring, for example, to the hourglass.
Thus, for example, it is known that during Diego de Magallanes’ trip around the world, all the vessels that participated in the expedition had several hourglasses to carry out absolute time control.
Currently, as you can imagine with the advancement of science and the realization of much more modern and functional proposals, hourglasses have stopped being used except, basically, in some board games.