THE ENGINEER AS WITNESS 43 



thus stated : " A witness may refresh his memory by referring 

 to any writing made by himself at the time of the transaction 

 about which he is being examined, or at any subsequent time, 

 if the Court considers it was then fresh in his memory, or even 

 if made by another person, if read within such time by the 

 witness, and if, when he read it, he knew it to be correct " 

 (Yearly Practice, 1908, p. 474). So the engineer called as an 

 expert to report as to the condition of the foundations of a 

 bridge would be entitled to refresh his memory by reference 

 to notes made by him or his assistant at the time. Indeed, if 

 it were not so, the task of giving evidence in reliance upon 

 the frailties of human memory would be hard indeed. An 

 expert may also refresh his memory by reference to profes- 

 sional treatises upon the subjects under discussion. It should 

 be remembered, however, that where any written memorandum 

 or treatise is used to refresh the memory, the witness must- be 

 prepared to produce it for inspection to the other side, who 

 are entitled to cross-examine him upon it. Some degree of 

 caution should therefore be used in making a reference to a 

 text-book. It may be out of date, and the author may have 

 embodied a different view of some particular theory in a 

 later edition. 



11. Cross-examination. The man who is prepared to give 

 evidence must be ready to withstand cross-examination. He 

 can best qualify himself for this ordeal by giving close atten- 

 tion to the case which has been, or which may be, put forward 

 by the other side. It is not enough that he should be able to 

 show that his own view is right, he must be prepared to show 

 that the other views are wrong ; and, if it is a jury case, he 

 must be able to explain himself in such a way that a juror 

 can understand him. It is true, of course, that many of the 

 judges are familiar with technical matters. Some, indeed, 

 have a considerable knowledge of scientific principles. Never- 

 theless, the expert witness should remember that he may have 

 to convince the mind of the layman. 



12. Previous statements of witness. A witness may be 

 cross-examined as to any previous statement made by him 

 relative to the subject-matter of the cause, and inconsistent 

 with his present testimony ; and if he either denies or does 

 not admit it, proof may be given that he did make it (Common 



