controlled by one or more than one employee, a device whereby, in
circumstances similar to those present in this case, the current, that
is, the motive power, would be disconnected immediately and
automatically. The Supreme Court was in error in affirming the
setting aside of the jury's verdict. The jury took the view that the
injury was not' the result of inevitable accident. Unless scientific
theories of experts are based on fact, their evidence is not of much
assistance to the court. The various forms of safety device have
not been adequately tested by the respondent. It cannot be con-
cluded, or even inferred, from the evidence that the installation
of safety devices would impose undue strain upon the drivers, or
impair efficiency, or increase the risk of accidents. The inference
must be to the contrary. The jury's rider shows that they fully
considered and appreciated the evidence. The opinion of the jury
as expressed in the rider was that the respondent was negligent
in not installing a safety device, but, having regard to the great
number and extent of its operations and the probability of mishaps,
the respondent was justified in taking the financial risk involved in
being found negligent in some cases, probably a few. A somewhat
similar rider was considered by the court in Ward v. Roy W.
Sandford Ltd. (1). On the evidence the jury was justified in arriving
at its verdict, and the Supreme Court was in error in affirming the
setting aside of that verdict (Williams v. Commissioner for Road
Transport and Tramways (N.S.W.) (2); Fitzpatrick v. Walter B.
Cooper Pty. Ltd. (3) ).