Abstract :
P. P. Ashworth: From a consideration of the line diagrams in this paper and in other papers presented, it would seem advisable for the Institute to adopt a set of standard symbols to be used by authors in these diagrams. This would make for clarity and simplicity. In Fig. 15 of Mr. Kelley´s paper the key to symbols is not given, thus detracting materially from the value of the diagram.
