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Clocks and instruments

CLOCKS
All watches from Delite Denmark and Fischer Germany have quartz movements. Most watches use AAA batteries LR06.

CLOCK with glass strike
Originally, ½-hour glasses were used on board the ships. Glas is the maritime term for each of the 8 time measures of ½ hour duration, which the watches at sea consist of, and which are indicated by striking the ship's bell with strikes for every half hour that has elapsed since the start of the watch. The 24 hours of the day thus consist of six 4-hour shifts.
An hour glass is a time meter consisting of two funnel-shaped glass containers turned with their tips towards each other and connected by a narrow opening, through which fine sand flows from one container to the other during half an hour.
A ship's clock with glass strikes marks the number of glasses (half hours) that have elapsed since the start of the watch. For example at 12 noon sounds 8 beats, it means: "The watch is over" - a new one begins and will end eight glasses later, at 16.
One of the advantages of a ship's clock with a glass strike is that you can also hear what time it is on the half hour, which can be helpful if you cannot see the clock.

The clock strikes glass every half hour in a four hour cycle

at 00:30 with a shot (glass)
at 01:00 double stroke
at 01:30 double stroke + one stroke
at 02:00 two double strokes
at 02:30 two double strokes + one stroke
at 03:00 three double strokes
at 03:30 three double strokes + one stroke
at 04:00 four double strokes
and then it starts all over again

THERMOMETER
A thermometer is a measuring instrument for measuring temperature.
The International Temperature Scale (SI unit) is the Kelvin scale, (which is not expressed in degrees, but 'only' XX Kelvin). In Denmark, the Celsius scale is used. In addition, there are, among others, fahrenheit and réaumur. The last three (as well as a few other scales) are all given in 'degrees'.
Thermometers can be constructed in different ways, depending on need and price. There are i.a. in the following types / uses:
Mercury: the old-fashioned 'fever thermometer',
Beckmann thermometer:  cannot measure absolute temperatures, but instead is able to measure very small differences in temperature. It was invented in 1888 by the German chemist Ernst Otto Beckmann (1853-1923)
Alcohol, with blue or red alcohol, outdoor / indoor thermometer,
Bimetal, usually round with pointers, like a frying thermometer,
Galileo - thermometer, the one with the spheres floating in some liquid. Mostly for decoration.
Digital, can basically replace all the above mentioned,
Infrared (IR), which can measure the temperature of surfaces (radiation of heat) without direct contact.

HYGROMETER
The relative humidity is the ratio of the current amount of water vapor to the maximum amount of water vapor that is obtained by condensation, which depends on temperature and pressure. Relative humidity is usually expressed as a percentage with values from 0% to 100%.
The amount of water vapor that is needed before condensation occurs increases with increasing temperature. Therefore, the relative humidity of an air mass will decrease if the air is heated, and correspondingly increase if the air is cooled. With continued cooling, the relative humidity will eventually reach 100% and the water vapor will begin to condense. Usually happens daily when the dew falls in the evening. The temperature to which a given mass of air must be cooled in order for this to happen is called the dew point of the mass of air.

THERMOMETER/HYGROMETER - COMFORT METER
The combination of thermometer and hygrometer is a fantastic thing, because a good temperature is not worth much if the humidity is too high - then it can quickly feel uncomfortable, even if the temperature seems right. You can also call it a comfort meter when it is combined with a thermometer. It is interesting that the temperature drops, even if it doesn't actually get wetter, the humidity increases and out in nature we call it the dew falling when it gets cooler in the evening. In a way, the coolness can wring the water out of the air.

BAROMETER
Barometer (Greek: gravity meter) is a measuring instrument for measuring air pressure.
Until the middle of the 17th century, the pressure due to the weight of the air (see air ocean) was not known, and it was not known that the air had weight at all.
Already from Antiquity, pumps and siphons were used, but it was assumed, like Aristotle, that their effect was due to what was called "Nature's horror of empty space" (lat. horror vacui). 1640 Galileo Galilei saw that a suction pump could not raise water higher than approx. 10 m, and he explained this by assuming that Nature's fear of empty space is limited. In 1643, Galileo's student Evangelista Torricelli took the case significantly further, and he assumed that the same unknown cause that could drive water up to a height of approx. 10 m, would only be able to lift the 13.6 times heavier mercury 1/13 of the 10 m, i.e. about 760 mm. To investigate this, Torricelli filled a glass tube with mercury. It was approx. 1 m long and fused at one end. He held a finger to the open end of the tube as he turned it upside down, and then lowered the open end of the tube into a container of mercury; when he then let go of his finger, the mercury in the glass tube really sank so much that it was almost 760 mm higher in the glass tube than in the open container. Torricelli concluded that the air, due to its weight, exerts a pressure that can be measured by the height to which the air can push mercury up in an empty space.
At the request of Blaise Pascal, in 1648 Perrier carried out a similar experiment on the top of Puy-de-Dôme, where it turned out that the mercury was only pressed up to a height of approx. 80 mm less than at the foot of the mountain. With this it was finally proven that the weight of the air is the cause of the air pressure, and that it is the same pressure that is the cause of the phenomena that had previously been considered as consequences of horror vacui. Torricelli's experimental device was the first barometer, and after him a barometer of the type he had used was often called a Torricelli tube, just as the empty space above the mercury in the glass tube has been named the Torricelli vacuum.
Already Torricelli noticed that the mercury did not always stand at the same height in the barometer, but that the mercury height could vary by a few centimeters, and he noticed that this variation was related to the weather conditions. A high mercury height was most common in good weather and a low height was most common in windy, rainy weather. The great use and spread of the barometer rests on that observation, and from here also comes its Danish, but now obsolete, name, weather glass, which can still be bought here at Nauticum.dk
No matter how fine and accurate a barometer measures, it must be calibrated based on the geographic location. Some of our barometers are manufactured in southern Germany, where the air pressure is slightly lower than on the coast of Denmark, where Nauticum lives. Which basis you use to find the correct current air pressure is a matter of taste, but a good bet is your country's weather map. There you can see the air pressure quite precisely and of course take into account where you live in the country. If you have several barometers, you will find that they can display differently until you get them calibrated. However, the less professional will be more affected by temperatures and humidity.

STORM GLASS and WEATHER GLASS
The storm glass and the weather glass are reliable barometers. Everyone who has one will consult it daily to get the weather forecast for the coming day. Others use it to predict when the fish will bite! Regardless of the application, there is no doubt that the storm glass and weather glass work. To date, however, no one has been able to provide a scientific explanation as to why. Admiral Fitzroy, director of the British Meteorological Institute, believed that it was static electricity from the fields that surround us. A revolutionary thought at the time!

Originally a barometer was called a weather glass and later a storm glass.
Barometer (Greek: gravity meter) is a measuring instrument for measuring air pressure. Until the middle of the 17th century, the pressure due to the weight of the air (see air ocean) was not known, and it was not known that the air had weight at all.

The weather glass is also a barometer, but instead of the crystals of the storm glass, you look at the liquid to see if it rises or falls. If the liquid in the large container falls, there is high pressure, and if the liquid rises, there is low pressure. When the quantity of the liquid changes, a change of weather is coming.

You get the most out of the storm glass by placing the storm glass in a cool place, e.g. in a north-facing window, or in a boat. As the name suggests, one should mainly pay attention to information about stormy weather a day or two ahead. However, a storm glass cannot completely replace the barometer - it can supplement it. Always remember to listen to the weather forecast! The storm glass is a highly valued utility item, and is often used as a gift idea. A piece of genuine Danish craftsmanship.

The crystals in the storm glass show what the weather will be like. Instructions are included with the item.

1. Fern-like crystals form = cold and stormy
2. Fern-like crystals disappear = warmer and improvement in the weather
3. Star crystals fall down = frost, possibly with snow
4. Crystals everywhere in the liquid = prospect of rain
5. The liquid is completely clear = fine and dry weather

The fern crystals stand highest on the side from which the wind comes.

GALELEI THERMOMETER
The Galilei thermometer is actually an old discovery, but still popular due to its beautiful appearance. The thermometer can be a little sluggish and a little pinch with the fingers is good.

Already from Antiquity, pumps and siphons were used, but it was assumed, like Aristotle, that their effect was due to what was called "Nature's horror of empty space" (lat. horror vacui). 1640 Galileo Galilei saw that a suction pump could not raise water higher than approx. 10 m, and he explained this by assuming that Nature's fear of empty space is limited. In 1643, Galileo's student Evangelista Torricelli took the case significantly further, and he assumed that the same unknown cause that could drive water up to a height of approx. 10 m, would only be able to lift the 13.6 times heavier mercury 1/13 of the 10 m, i.e. about 760 mm. To investigate this, Torricelli filled a glass tube with mercury. It was approx. 1 m long and fused at one end. He held a finger to the open end of the tube as he turned it upside down, and then lowered the open end of the tube into a container of mercury; when he then let go of his finger, the mercury in the glass tube really sank so much that it was almost 760 mm higher in the glass tube than in the open container. Torricelli concluded that the air, due to its weight, exerts a pressure that can be measured by the height to which the air can push mercury up in an empty space.

Galileo discovered that the volume of a liquid changes with temperature. As the temperature rises, the volume of the liquid increases, while the glass spheres hardly change. During the expansion, the density of the liquid decreases. The balls' buoyancy = the mass of the displaced amount of liquid. As the temperature increases, the fluid's ability to carry the balls decreases. The balls have a difference of a few milligrams in weight and therefore sink differently depending on the temperature.
The Galileo glass has 4 glass spheres 18, 20, 22 and 24ºC.

At 19ºC, the 18ºC ball can only float exactly. When the temperature exceeds 19ºC it will decrease.
Now the 20ºC sphere will be visible for reading. As the temperature rises further and passes 21ºC the 20ºC sphere will sink and the 22ºC sphere will be visible for reading etc.
Thus, when the temperature is read as 20ºC on the Galilean glass, the temperature will in reality be between 19ºC and 21ºC.

So the temperature is read on the lower of the upper spheres - regardless of whether the glass has 7, 10 or more spheres.
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