Some of my (busman’s) holiday reading was about the 1931 “blazing car” murder trial.

I would be surprised if many recognised the case name, but R v Rouse is the source of an often-quoted example of an expert who was completely discombobulated by a curly first cross-examination question, in this case: “what is the coefficient of the expansion of brass?”

The effect on the expert’s evidence was such that the jury was later instructed to consider the truth of his opinions “irrespectively of whether he appeared rather foolish” in giving them!

Background

Albert Rouse suffered serious injuries from his service in World War One. Following his return and his recovery from his wounds, he worked as a commercial traveller for a company selling braces.

In late 1930 Rouse took out a £1,000 life insurance policy naming his wife as beneficiary, and attempted to fake his own death by setting his car on fire.

He visited a lover (one of several, it transpired) immediately after the fire.

She identified the burnt-out car as his from a newspaper photograph, and contacted the police.  He was swiftly arrested, and charged with the murder of the unidentified man whose body was found in the car.

The circumstances were newsworthy in themselves, but the case attracted even more public attention following newspaper reports that Rouse had several children via at least three bigamous marriages, and that he had described his lovers as a “harem” and “an expensive game.”  It appeared that his plan to fake his death was an attempt to secure a ‘fresh start,’ free from obligations to financially support his children.

Rouse told the police that his car caught fire when he had stopped to answer a call of nature.  He said that he asked his passenger – a hitchhiker, whose identity he did not know – to fill the petrol tank from a jerry can, and speculated that the hitchhiker’s cigar had ignited petrol fumes, causing the fire.  He told police that he had tried and failed to rescue the passenger – somehow now trapped inside the car – and had then panicked, and fled.

A forensic examination identified a loose joint on a pipe between the fuel tank and the carburettor.  The prosecution case was that Rouse, apparently a handy amateur mechanic, had loosened the nut on the union joint to speed the flow of petrol.  The defence argued that the union nut was loosened by the fierce heat from the fire, and that no human agency was involved.

The Expert Evidence

Expert evidence was provided about the position of the body in the car – whether the body been placed in the car; the cause of the fire; and the loosening of the union nut, which is the focus here.

The expert whose confidence was so shattered by Birkett, Mr Isaacs, was not an expert as is normally engaged – rather, he was one of two “public spirited volunteers”[1] who came forward following newspaper reports of the evidence provided by the prosecution expert, Colonel Buckle.[2]  Buckle was an electrical engineer by training with extensive experience in fire investigation, who testified that the union nut was a “full turn loose,”[3] and that it was inherently unlikely to have become loose, accidentally.

Isaacs gave evidence contradicting the opinion of Colonel Buckle: that in his practical experience as an insurance fire investigator “it is invariably found at all fires that have been very intense that [such] nuts are loose.”[4]

The famous challenge to Isaac’s credentials is as follows:[5]

Birkett: “What is the coefficient of the expansion of brass?”

Isaacs: “I beg your pardon?”

Birkett: “ Did you not catch the question?”

Isaacs: “I did not quite hear you.”

Birkett: “What is the coefficient of the expansion of brass?”

Isaacs: “I am afraid I cannot answer that question off hand.”

Birkett: “If you do not know, say so. What is the coefficient of the expansion of brass? What do I mean by the term?”

Isaacs: “You want to know what is the expansion of the metal under heat?”

Birkett: “I asked you what is the coefficient of the expansion of brass? Do you know what it means?”

Isaacs: “Put it that way, probably I do not.”

Birkett: “you are an engineer?”

Isaacs: “I daresay I am.”

Birkett: “Let me understand what you are. You are not a doctor?”

Isaacs: “No.”

Birkett: “Nor a crime investigator?”

Isaacs: “No.”

Birkett: “Nor an amateur detective?”

Isaacs: “No.”

Birkett: “But an engineer?”

Isaacs: “Yes.”

Birkett: “What is the coefficient of the expansion of brass? You do not know?”

Isaacs: “No; Not put that way”

The question was unplanned – in “The Art of Advocacy” Birkett said:[6]

…whether it was inspiration or what it was I don’t know, but my first question in the cross-examination of the man certainly wasn’t in the brief. I said, “Tell me, sir, what is the coefficient of the expansion of brass?” And he didn’t know. I am not sure that I did, but he couldn’t ask me questions and I could ask him, and he didn’t know. And from that moment, of course, it was easy.

The other volunteer, Mr Cotton, was a colleague of Isaac’s, and he gave similar evidence.  Birkett asked him a similar question, which he dealt with more confidently:[7]

Birkett: “You know the coefficient of the expansion of metal?”

Cotton: “I am afraid I cannot answer that question.”

Birkett: “They are in any little diary that an engineer has. Have you got an engineer’s diary?”

Cotton: “Yes.”

Birkett: “Does it contain all the coefficients of expansion??”

Cotton: “Yes, But I do not study them.”

It is not clear whether the coefficient of the expansion of brass was in important issue.  Birkett’s acknowledgement that he did not himself know the answer to the question that he asked, suggests that it was not, and he did not raise the matter of the loose union nut in his closing speech.

In summing up Justice Talbot said:

I do not think anybody would say that Mr Isaacs made a very brilliant appearance in the witness box, but you may think, and probably will think, that that was mostly because he did not confine himself, as he more prudently would have done, to what he knew…but it does not mean that he is not telling me the truth about his experience. That is a matter which you might weigh quite irrespectively of whether he appeared rather foolish when he was tackled [about] the cause of this phenomenon.

Outcome

Rouse was found guilty.  That verdict was confirmed on appeal (which rejected extensive new evidence about the tendency of union nuts to loosen by themselves), and he was executed.  Prior to his execution he wrote a letter to a newspaper in which he said:[8]

Then I got out of the car, taking my attaché case, the can of petrol, and the mallet with me. I walked about 10 yards in front of the car and opened the can, using the mallet to do so. I threw the mallet away and made a trail of petrol to the car. I took the mallet away with one purpose in view. Also I poured petrol over the man and loosened the petrol union joint and took off the top of the carburettor. I put the petrol can back in the back of the car.

I ran to the beginning of the petrol trial and put a match to it. The flame rushed to the car which caught fire at once. Petrol was leaking from the bottom of the car. That was the petrol I had poured over the man and the petrol that was dripping from the union joint and carburettor.

The fire was very quick and the whole thing was a mess of flames in a few seconds.

His victim remains unidentified.[9]

Comment

Neither Isaacs nor Button (nor those providing new evidence for the appeal) were able to provide a scientific reason to explain the practical experience to which they testified.

Birkett dealt with Isaac’s evidence quickly and effectively – but it appears that he was dealing with a problematic opinion advanced by an inexperienced and under-prepared expert (if that), which may equally have been dealt with by a more orthodox cross-examination.

Notes:

[1] “The Trial Of Albert Arthur Rouse,” Helena Normanton, page xxxi.

[2] Normanton, page 241.

[3] Normanton, page 60.

[4] Normanton, page 241.

[5] Contemporary reporting from each of The Times and “The Trial Of Albert Arthur Rouse” Sydney Tremayne (at page 290); records a slightly different exchange to that recorded in Normanton at page 244 and shown here.

[6] 1048 The Canadian Bar Review 1947, (www.cbr.cba.org/index.php/cbr/article/view/1346).

[7] Normanton, page 253.  Tremayne (page 296) does not record the question being put to Cotton, but The Times does.

[8] Normanton, Appendix II, page 297.

[9] See https://www.bbc.com/news/uk-england-northamptonshire-33426167.