It was agreed that "lay assistants" were allowable, but only in cases of necessity.
The act had always been accounted allowable in the school, if circumstances should call for it: indeed, the first three teachers had found such circumstances.
As has been remarked above, the terror of postbaptismal sin and the fact that only one restoration was allowable influenced many as late as the 4th century to remain catechumens all their lives, and, like Constantine, to receive baptism on the deathbed alone.
Given a certain allowable heat transmission, the principal points to be considered in connexion with insulation are, first cost, durability, weight and space occupied, the two last named being specially important factors on board ship. No exact rules can be laid down, as the conditions vary so greatly; and though experiments have been made to determine the actual heat conduction of various materials per unit of surface, thickness and temperature difference, the experience of actual practice is at present the only accepted guide.
It is a well-ascertained fact that the insulator, gutta-percha, is, when kept under water, practically imperishable, so that it is only the original strength of the sheathing wires and the deterioration allowable in them that have to be considered.