There have been many, many famous Yorkshire men and women who made an impact on the world.

There are far fewer who actually changed it. James Cook, famously the only Yorkshire captain to tour Australia without playing in a single test match, was one. John Harrison, the watchmaker whose precision chronometers made navigation on explorations like Cook's possible was another.

But what about the Yorkshireman who should be remembered every time you pop a fizzy drink can or unscrew the top of a pop bottle?

His name was Joseph Priestley and he came from Fieldhead at Birstall, where he born in 1733 and where, at the moment, his life is being recalled in a series of exhibitions and talks.

He is best remembered as the scientist who discovered oxygen and, by experiment and deduction, showed that water was a combination of oxygen and hydrogen. He did this at about the same time that the eccentric and painfully shy Englishman Henry Cavendish, and the French 'Founder of Modern Chemistry' Antoine Lavoisier were coming to the same conclusion.

Lavoisier, though he had the greater reputation, generously acknowledged that Priestley had done the major work first on the subject.

Priestley went on to do work with other gases, including one which had been a mystery for years - for as long, in fact, as humans had been brewing beer or making bread.

It was the gas which made bread rise, and which yeast produced when ale was fermenting in the brewery.

Priestley, curious about this stuff, went to a brewery in Leeds and began experiments with the blanket of heavy, odourless gas which lay above the froth in the brewing vats.

He found that a candle lowered into it went out.

He found that small animals lowered into it died (although if you did the same things with oxygen, the candle burned brighter and the animal became more lively).

Whatever it was, it wasn't ordinary air and, because the chemical words and formulae needed were still being invented by Lavoisier, it was a while before it became known as carbon dioxide.

But Priestley, an inveterate experimenter, soon made another discovery about his new gas. It dissolved in cold water.

He proved this by pouring water from one glass to another and back, dozens of times, just above the surface of the beer. After a while bubbles began to form on the side of the glass and, when the water was tasted, it fizzed upon the tongue.

This was not, of course, new. Water in limestone areas had been bubbling out of the ground in springs since time immemorial, and often it was naturally gassy. But because it wasn't too common, it was also naturally expensive.

What Priestley had done was manufacture carbonated water; or, as it became known, soda water (although it didn't contain soda in any form)

In those days anything new was reckoned to be healthy. Electricity passed through the human body was once supposed to be good for most ailments. Deadly radiation was also regarded as beneficial.

So Priestley's discovery was soon being touted as the new health drink (despite the fact that beer had just as many burps to the bottle as soda water).

Priestley could have made a fortune but he was not a popular man in England. He espoused the cause of the French Revolution and had been on the side of the 'rebels' in the American War of Independence. Such radical opinions were not welcome among the patriotic, the xenophobic or the plain stupid, and in 1794, finding himself cold-shouldered for his opinions, Priestley sailed for the new America, where he died in 1804.

And where, to this day, nobody talks about pop - they call it soda...

How a hungry PC beat the system...

Ello 'ello 'ello! Our piece on police boxes last week stirred a few memories. It rattled a few skeletons, as well.

Former Inspector Maurice Ackroyd, who used to be Community Relations Officer with the old Bradford force, writes recalling the days when beat bobbies had their mid-shift meal on day duty in the cellar at City Hall where there was a room with tables and benches, a kettle and a large open fire.

Officers were provided with canvas satchels to carry their sandwich boxes.

There was also a police canteen in Chapel Lane, between Norfolk Street and Bridge Street.,

At night, bobbies had a number of places to eat - by arrangement with the owners. Busbys in Manningham Lane, the waterworks depot in Belmont Street and night watchman's offices in various mills were designated, as were the police boxes.

But Maurice recalls that the electric stove in the police box was often slow in bringing a kettle to the boil, so a bit of subterfuge was needed. A smart bobby would nip in early to put the kettle on.

'This had to be done without attracting the sergeant's attention' says Maurice. 'One of the most important items in the box, as far as the system was concerned, was the register, a book which was ruled in columns headed 'date', 'time in', 'time out', 'reason for visit' and 'signature'

'Unauthorised visits were strictly forbidden'.

There were 106 red police boxes in Bradford. Some had room enough for one officer, others were larger, and the one at Lidget Green was a sub-divisional station.

Maurice recalls the story of an inspector who was examining the register at one box and was appalled to see, in the 'reason for visit' column, the words 'sheltering from rain'.

He arranged for the bobby in question to be hauled before him for a right royal rollocking.

What, demanded the inspector, was the reason for this entry?

The accused explained that it was his day off at the time.

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.