[This discussion applies also to the papers by MR. J. D. WATSON (p. 449),MR. JAMES CRABTREE (p. 453),MR. G. BERTRAM KERSHAW (p. 456),MR. J. E. PURVIS and MR. E. H. BLACK (p. 466),and PROF. E. A. LETTS and MR. CHARLES W. ADDY (p. 472).]

[This discussion applies also to the papers by MR. J. D. WATSON (p. 449),MR. JAMES CRABTREE (p. 453),MR. G. BERTRAM KERSHAW (p. 456),MR. J. E. PURVIS and MR. E. H. BLACK (p. 466),and PROF. E. A. LETTS and MR. CHARLES W. ADDY (p. 472).]