The correspondence following NCE's article on bridge corrosion caused by human urine reminded me that this problem is not confined to the construction industry.
I can recall a plane crash in northern Canada that was attributed to lumberjacks not being very careful when they used the toilets at the rear of the aircraft.
The result was that the airframe structure became corroded and eventually fractured.
Don Westcott, Don Westcott Associates, 9 Kent Court, Queen's Drive, West Acton, London W3 0HS
Oxford restored to former glory
In response to S Fisher's letter (NCE 3 February) we would point out that the essential business of Oxford lies in its history; its colleges, churches and institutions.
In the months since cars have had limited access and buses have been rerouted much of the beauty of the city has been restored.
We may have to shop for food, DIY and furnishing in other towns but we are no longer choking the atmosphere in this rare and grand area of British heritage.
Alan (M) and Mary Reed, alanmaryreed@compuserve. com.