The Summer 2002 issue of the Bar News had an item in the Verbatim column which quoted a question asked during the Esso class action. The question was “What is the coefficient of the expansion of brass”. Some in court were mystified by the question; some who read the account of it in the Bar News were mystified by it. (The question itself was relevant (tangentially at least) to the mechanism by which a hot water service might fail if allowed to cool completely and then undergo reheating.)
Still, it was interesting that many readers did not recognise the question as a quote from a famous cross-examination in a famous case.
Alfred Arthur Rouse was a commercial traveller. He was a vainglorious man who seems to have been irresistibly charming to some women: he maintained wives and mistresses around the countryside, and visited them in the course of his journeys around the countryside as representative of Messrs Martins, garters and braces. Each was apparently unaware of the existence of anyone else in Rouse’s life. If nothing else, his complex social life may explain some of his curious conduct when events began to unravel.
At about 2 o’clock in the morning of 6 November 1930, two young men – Brown and Bailey – were walking home from their Guy Fawkes night revels near Hardingstone, near Northampton. A well-dressed man carrying an attaché case climbed out of a ditch in front of them, walked past them without a word and turned uncertainly from Hardinsgtone Lane into the Northampton Road. Bailey then noticed a glow some 400 yards away and asked what it was. The man with the attaché case said “It looks as if someone has had a bonfire down there”. Brown and Bailey later positively identified Rouse as the man with the attaché case. As Brown said during re-examination: “When you go home at that time in the morning you do not usually see well-dressed men getting out of the ditch.”
Brown and Bailey ran towards the “bonfire”; Rouse made his way to the main road and ultimately hitched a lift to London. When Brown and Bailey got to the fire, they found it was a Morris Minor which was blazing fiercely. The number plate was clearly visible: MU 1468. It was Rouse’s car. They called the police. When the fire had been put out, a charred body was found in the front seat of the car. In addition, police found an empty jerry-can. On closer examination of the wreck, it was discovered that the petrol cap was on, but loose, the top of the carburettor was missing, and that a junction in the petrol line was loose. The junction was in a position that petrol in the fuel line would drip into the foot-well of the car.
Rouse hitched a lift to London. He told the driver that he had been waiting for a colleague to pick him up in his Bentley. He did not mention that his own car had just burst into flames. Whilst in London, he told a stranger at a coffee-stall that his car (which he described as a Wolseley Hornet) had been stolen. He then caught a coach to Wales. During the trip, he told the coach driver that his car had been stolen. Later that day he reached Gellygaer where Ivy Jenkins lived with her family. Rouse was having an affair with Ivy. Rouse told Ivy’s father that his car had been stolen the day before. Shortly, a colleague of William Jenkins came to the house, and said that there was a photograph in the paper of a car which had burnt the previous day. Seeing the photograph, in which the numberplate was very clear, Rouse said it was not his car. Later still that day, Ivy’s sister told Rouse that there was a photograph of his car in the paper: she showed him the article, in which he was named as the owner. He asked her if he could take the article, put it in his pocket and left the house.
When Rouse returned to Hammersmith by coach, Detective Sergeant Skelly met him. Rouse said “Very well, I am glad it is all over. I was going to Scotland Yard about it. I am responsible”.
The trial before Justice Talbot began on 26 January 1931. Norman Birkett KC and Richard Elwes appeared for the prosecution. Rouse was defended by D.L. Finnemore. The Crown could not suggest a motive for the alleged murder. Neither could they identify the body, so nothing could be suggested about the deceased which might explain an otherwise senseless killing. The principal forensic dispute concerned the way in which the fire started. Finnemore tried to establish the possibility that the fire started accidentally. He sought to suggest that the junction nut might have been loosened by the passenger’s foot, but the experts flatly rejected the possibility. It was against that background that Arthur Isaacs was called by the defence on the fifth day of the trial. He gave evidence that he was “an engineer and fire assessor with very vast experience as regards fires in motor cars”. He advanced the theory that the junction in the fuel line had become loose in the course of the fire, as a result of the fire itself. He gave his evidence with great confidence.
The cross-examination began as follows:
What is the coefficient of the expansion of brass? — I beg your pardon
Did you not catch the question? — I did not quite hear you
What is the coefficient of the expansion of brass? — I am afraid I cannot answer that question off-hand
What is it? If you do not know, say so. What is the coefficient of the expansion of brass? What do I mean by the term? — You want to know what is the expansion of the metal under heat?
I asked you: What is the coefficient of the expansion of brass? Do you know what it means?— Put that way, probably I do not.
You are an engineer? — I dare say I am.
Let me understand what you are. You are not a doctor? — No
Not a crime investigator? — No
Nor an amateur detective? — No
But an engineer? — Yes
What is the coefficient of the expansion of brass? You do not know? — No; not put that way.
(The coefficient of thermal expansion of any substance is the measure of the extent to which its size changes as its temperature changes. All substances change their volume as their temperature changes. The change is usually linear, although water is an exception: the coefficient of thermal expansion of water alters as the temperature approaches zero degrees Celsius.)
Birkett was criticized for these questions. It was said that the questions were unfair. It may seem a bit adventurous to expect a witness, however expert, to have the correct number at the top of their mind. Birkett later said that, if the witness had known the answer, he would have then asked the coefficient of expansion of aluminium (of which the carburettor body was made) and would then have moved on to other matters. On any view it perfectly legitimate for him to expect that the witness would understand the concept which was fundamental to his evidence.
Callaway JA has suggested, extra-curially, that the key question was unfair in other ways. It is true that the question would have been more precise if it had asked for the linear coefficient of thermal expansion. Nevertheless, most genuine expert witnesses would assume those details, and would ask for clarification if in doubt. Clearly, Mr Isaacs would not have been helped by the greater precision. A more telling point made by Callaway JA is that the question should have identified the precise composition of the brass. Brass is an alloy of copper and zinc, but the proportions are not fixed. Since copper and zinc respectively have different coefficients of thermal expansion, the question as framed has no single answer. If Mr Isaacs had been a genuine expert, he could have devastated Birkett with a different response to the first question:
What is the coefficient of the expansion of brass? — I assume you are asking for the linear coefficient of thermal expansion, but can you tell me the precise proportion of the constituents of the alloy?
It would be impressive indeed if Birkett had been able to respond accurately.
Rouse was found guilty of murder. His appeal was heard on 23 February 1931. Sir Patrick Hastings led Finnemore on the appeal. The appeal failed. Rouse was hanged at Bedford gaol on 10 March 1931.