ABSTRACT
In his prefatory remarks to the following paper, read at a meeting of this Society, Mr. Hutton says his aim ‘was above all to be practical, but it was impossible in the limits originally prescribed to include therein everything connected with the subject. Some points which some may consider of importance may have been omitted; it is thought, however, that the main points taken up are sufficient to suggest what further work should be done by an auditor”:—
