Aristotelians believed that air didn’t have weight and therefore couldn’t be the cause of the movement in the level of the surface of the water. If this was so then how could they explain the rise and fall of the water? Even Galileo thought that, although there were miles of air above us, it didn’t weigh down on us. Not withstanding the fact that it was he who dropped various articles from the tower at Pisa to show that gravity affected object of different weight in the same way.

Torricelli doubted that air was weightless and strove to prove that it was barometric pressure that affected the level of the water. It was his contention that it was air pressure and not the attractive force of the vacuum that affected the level of the fluid.

The fact that water would stay at thirty four feet was more reflective of the air’s pushing the water up the tube than it was with the weight of water pushing down and the vacuum it created sucking it back up. Because he saw the that the water would only rise to a certain height he saw that the barometer was in fact an instrument by which measurements could be made, rather than simply as a means to create a vacuum.

Torricelli was briefly a student of Galileo, and it was he who suggested the notion of experimenting with different liquids to see which would stop at different levels. Torricelli experimented with liquids like wine and mercury, discovering that mercury was so heavy that it found its level at a far more user friendly height than any other.

Because mercury is fourteen times more dense than water it stops rising fourteen times lower than water. If air were indeed weightless it would not impact on the height at which any fluid rose to, therefore air has weight.

Now that the experiment could be brought into a laboratory (previously experiments had to be carried out in or around high buildings) it was possible to detect slight changes in the level of the mercury from day to day. Because Torricelli knew that air had weight these changes had to be dependent on changes in weight or pressure. It wasn’t long before trends started to appear: high pressure brought good weather while low pressure bought rain, wind and higher tides.

The problem with mercury barometers was that they were filled with a toxic heavy metal, they were heavy and they couldn’t be moved easily as any spillages or leaks would ruin them.

Today it’s possible to use a Weather Station instead, these are digital devices which can sit on a shelf or desk and give you a plethora of information, including not only air pressure but humidity, interior and exterior temperature and if you have data transmitters in the green house, the garden and a cellar you can monitor them all individually.

Bad Weather Ahead

The seas around the British Isles are divided up into 31 separate sea areas and twenty four hour forecasts are broadcast at 11pm, 5am, 11am and 5pm. The forecast contains warnings of gales, storms and rain as well as visibility and wind direction and force. However, if you don’t know what you’re listening to the information may seem to be confusing at the very least.

For example the meteorologist may say:

“Cromarty, Forth, Tyne. Storm force 10 veering northwesterly, decreasing gale force 9 imminent. Northwest 7 to severe gale 9 decreasing 5 or 6 backing southwest 4 or 5 later. Rough or very rough becoming moderate or rough. Squally showers then fair. Good occasionally poor at first.”

The first part relates to shipping areas where ferries, container ships, fisherman and also aircraft might be, the forecast names them as they appear in a clockwise direction around the British Isles so Cromarty, Forth, Tyne describes a sea area stretching from John O’Groats down the eastern coast of Scotland past the border into England down as far as the southern side of the Tyne estuary. The next part is a storm or gale warning, the numbers are wind speeds based on the Beaufort scale where zero means a flat sea and, inland, smoke would rise directly upwards up to twelve which would be a hurricane, waves would be above fourteen metres, inland trees would be blown over, windows break and structures such as sheds and mobile homes are damaged along with objects being thrown about. Veering means a change in the wind’s direction, veering means that the wind will be changing clockwise as it turns, if it were to change anticlockwise it would be described as ‘backing.’ When winds are above force 8 they are also given their name for emphasis, hence “severe gale 9 decreasing 5 or 6.”

The next portion describes the sea conditions, in this case there is a storm so, as you would expect, conditions are rough, precipitation is also given, although there are high winds are expected not a great deal of rain is so we have “squally showers or fair” not withstanding the fact that the wind will be blowing a great deal of spray. The final section is visibility. If (excluding spray) visibility is expected to be more than 5 nautical miles (9.3km) it is defined as good, moderate describes visibility between 2 and 5 nautical miles, poor there visibility stretches from a kilometre to 2 nautical miles down to fog where visibility is less than one kilometre.

Now, recent studies and reviews of previous work  suggest that maintaining an indoor  Relative Humidity (RH) level between 40-60% can not only relieve cold and flu symptoms, it can actually help kill flu viruses on surfaces and in the air if used with other measures.

Research that studied the correlation between why the influenza season peaks in the winter months when air temperature and RH levels are so low concluded that the survival of influenza germs can be reduced significantly by using humidifiers to create RH levels of at least 40%.  Using mechanically atomised influenza virus samples released as an aerosol to infect chicken eggs or egg membranes, studies consistently show that influenza survives far better at low RH levels.    Although not as extensively studied as the effects of RH on aerosol survival, studies on the effects of RH on influenza survival on hard surfaces also showed a similar correlation.  The data across several studies is remarkably consistent.  Influenza germ survival is greatly reduced in environments with an RH of approximately 40 -60%.

Of course, this only reduces influenza germ survival rates and there is still no cure for the common cold. There are things you can do to alleviate any symptoms and using a humidifier is definitely one of them. Maintaining the right amount of moisture in your home can help to soothe sore throats and allow you to breathe better and sleep more comfortably.   Even when the whole family is healthy, proper humidity levels in the home can relieve other winter symptoms caused by cold, dry winter air, such as a dry nose, a dry throat, and dry eyes.

Works anywhere in the house and using outdoor transmitter gives us an accurate reading of greenhouse temperature all day at a glance.

It has very accurate forecasting.

Gives us a calendar and perfect time of day and constant humidity reading.

We love it and utilize it every day. What did we do without it???

The only negative side is that the outdoor transmitter needs to be sheltered from the elements.

This is my first foray into weather data collection and I searched long and hard to find a suitable unit. I wanted something semi-professional but that didn’t cost a small fortune.

After comparing lots of systems, I plumped for this German built unit. It hasn’t let me down and I am now completely hooked!

You get: One base unit, one outdoor sensor (temperature and humidity), one rainfall sensor and one anemometer (wind sensor).

The first base unit I received did have a small issue with one of the LCD display bars (it wasn’t working) – but my replacement unit is perfect.

Since then, I have been receiving and logging data continuously. Once a week, I connect the unit to my PC (via the supplied USB cable) and upload all the data I have received.

The system comes with a copy of ‘WeatherView’ which is some software for logging and displaying the various data types. It’s dead easy to use and you can view graphs and various displays of all the information you have received. The actual underlying files can be opened by Excel too.

But what I really love about this unit is it’s fantastic flexibility. For example, all the ‘units’ for the measurements can be displayed in multiple ways; mph/kph/ms/knots for wind speed, inches/mm for rainfall, Millibars/inches for pressure etc etc.

You can display the clock in 12 hr/24hr, you can have time and date displayed, time and seconds, time and day, time and city or just the month and day!

You can set alarms for certain wind speeds, alarms for specific rain fall, alarms for temperature etc. You can also have a weekly repeating alarm, a ‘one time only’ alarm and a ‘pre alarm’ for low temperatures!

The system displays the current moon phase and you can manually scroll forward or backward through time to see what the phase is/was on any given day.

The system will display the current sunset time and sunrise time for your location. You can either choose from the dozens of pre-set city locations or you can manually enter your precise longitude and latitude location. Excellent stuff! Again, you can scroll forward or backwards through time and see the sunset/sunrise times update accordingly. A nice touch.

It’s really well thought out and seems to have been designed by intelligent people!

You can have up to five external temperature/humidity sensors (therefore, you could buy an additional four). All details are received and logged and you can view them through different channels on the base unit.

Data logging (within the base unit) can be set to every 5 minutes to every 24hrs.

The unit sits on my bedside table and is my alarm clock (complete with manually configurable snooze duration). It has a gorgeous backlight which you can manually turn on or you can set it to come on automatically when light levels in the room drop.

I love checking my Nexus just before going to bed – seeing what the weather is doing outside and also seeing what the unit predicts the weather will be in 12/24 hours time. It’s a brilliant bit of kit.