A magical meteorological tour at UK Science Museum Archive

A hygrometer at the UK Science Museum Archive. This instrument is about 15cm high, and was made around 1825. Hygrometers measure the moisture in the atmosphere. The cloth covering the bulb on the right would have been made wet and as the water evaporated, the thermometer hanging on the left would have recorded the drop in temperature. Using the evaporative temperature and the temperature recorded by the thermometer in the middle, the observer could then calculate the relative humidity of the air. Image used with permission from the UK Science Museum.

 

by LINDEN ASHCROFT
PhD Student The University of Melbourne
UK Science Museum trip partly funded by ARCCSS

 

Earlier this year I was lucky enough to visit the archives of the UK Science Museum in London. My PhD research at the University of Melbourne is focussed on historical weather records in Australia, and my mission in London was of a grand scale. More accurately, my mission was FOR a grand scale: I was searching for the registers and scales on old meteorological instruments, to determine their accuracy.

The Science Museum is responsible for over 180,000 historical scientific instruments and objects, but only around 10% of the Museum’s collection is on display at any one time. The rest of the instruments are stored at several off site archives, including Blythe House in west London.

Blythe House is a historical object in its own right, as it was originally built in the early 1900s to be the headquarters of the Post Office Savings Bank. Collections from several museums are stored in its 270 rooms, but it was the scientific instruments I was there to see.

Feeling like Indiana Jones but without the hat, I arrived at the archives excited and ready to explore. The curator led me through warren-like corridors and into room after room of old, dusty science memories.

The first room was the largest, and it was a veritable Room of Requirement filled with thousands and thousands of scientific objects. There was glass chemistry equipment, huge telescopes, giant old world globes and, importantly for me, a large collection of old meteorological equipment.

Carefully I examined over 40 large barometers, thermometers, early wind vanes, and hygrometers that dated back to the early 1700s. It was amazing to think of delicate instruments like these making it all the way to Australia.

As we moved through the rooms, examining older and more fragile instruments, it was clear that the range of meteorological equipment used in the 1800s varied wildly.

 

The scale of a marine barometer made in the mid-1800s in the UK. The complete instrument was around 80cm long, and the scales (pictured) were located at the top. The observer (often a sailor at sea) would read the temperature on the left and then the pressure on the right, adjusting the small sliding scale to get a pressure reading to the nearest 100th of an inch. Note the different temperatures marked on the right hand side of the thermometer. Image used with permission from the UK Science Museum.

 

Some instruments were intricate works of art, designed to hang on the walls of well-to-do houses. Others were simple and easy to read, for mariners and fishermen who needed to check the daily weather before heading out to sea. These instruments had low-resolution scales, and were not built for scientific observations.

Many other instruments however were designed for accuracy, and had scales to the nearest 10th of a degree Fahrenheit, or 100th of an inch of mercury. One thermometer I saw had the temperature of a number of different places and animals, including the temperature of a swarm of bees, the temperature of ‘domestic quadrupeds’, the temperature at which tins melts, along with the temperature of the hot water pump in the town of Bath.

The variety of instruments I inspected at Blythe House now gives me a good idea of the equipment used to record some of the earliest weather observations in Australia in the late 1700s and early 1800s.

Understanding the accuracy of the scales, the fragility of the instruments, and any biases that these scales may have will help me to determine how reliable the early observations are. I can then get a better understanding of how useful these observations could be in reconstructing our past climate.

Many thanks to the Centre of Excellence for Climate System Science for partially supporting this trip, and to Becky Storr at Blythe House for all of her patience and assistance on this adventure.

Linden Ashcroft is a PhD student at the University of Melbourne’s School of Earth Sciences. Her work is on early instrumental weather records in southeastern Australia, and what these records can tell us about the impact of climate features (such as El Nino—Southern Oscillation) on long-term southeastern Australia climate.

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