In the matter of expert service in the courts I am disposed to speak
guardedly. I see no reason why an engineer should not willingly go upon
the witness stand to give expert testimony if he has made proper
preparation and has an honest conviction that his testimony can be given
with a conscientious regard for the obligations of his oath as a witness.
It is his duty and his privilege to defend his opinions, for the man
without opinions which he is prepared to defend is worthless as a witness
and cannot properly be called an expert. But the conscientious engineer
has no right to appear as a partisan of anything except what he believes
to be the truth. If he finds himself parrying the questions of the
cross-examination with a view to concealing the truth, if he realizes
that he is a partisan of the side which retains him, and feels a
temptation to earn his fee by falsehood, concealment, or evasion, he can
be sure that he is in a position in which no man of honor has a right to
be. The abuses of expert testimony in civil and criminal suits are many
and grave; its uses are perhaps exaggerated, and the witness stand is not
an inviting field for the young engineer seeking a satisfactory career.

How far an engineer can properly use for his own advantage information
gained in the discharge of duties of a confidential nature, is a question
at once delicate and difficult. He cannot help knowing what he has
learned, and his knowledge is his capital. He must be governed in this
matter by the considerations which influence men of honor in the ordinary
relations of life. Stock and real estate operations, on confidential
information which belongs to one's principals, are usually in violation
of the simplest rules of professional honor. The manager who advises his
brokers by telegraph and his principals by mail cannot, I think, claim to
have a very delicate sense of right and wrong. He can judge his own
conduct by the standard he would apply in judging like infidelity on the
part of those employed by him.