TRAYS.--The most unsuitable and damage-causing part of the vast majority of machines, without doubt, is the tray. On nearly all machines the tray is wider than the effective portion of the rolls, so that any excess of lubricant may drop into it. On others, not only is the tray wider than the rolls, but its edge either is in contact with the shaft of a roll or just a small distance away. The edge of the tray is thus favourably situated for acting as a "wipe," and the lubricant is transferred to the inside of the tray. Considering that the effective portion of rolls is about two-thirds of their length, it must be unnecessary to have trays wider than the length of the rolls. For the preparation of fine crepe trays are quite superfluous, and their place can be taken by a narrow piece of board if required. If the bed of the machines has been covered with glazed tiles, even a piece of board is not necessary. Where trays have been removed from the fine-crepe rolls on a number of estates, a marked decrease in the number of spoiled pieces of rubber has resulted. It must be recorded that the foregoing paragraph appeared in our 1913 publication. After a lapse of over seven years, the remarks remain as true as when originally written. One of us is continually meeting with cases in which the defects are plainly attributable to the cause indicated above, and the fault often lies with the management of estates. On most machines the trays are not fixtures, and could be removed if desired. ARRANGEMENT OF MACHINES.--In considering the future arrangement of machines, the first care should be to see that machines and windows are to be found together.[16] Of all the factory operations, rolling of rubber should be given the maximum light. At the same time it would not be advisable always to choose a southern aspect, unless outside shades were supplied. The best position for setting up machines, therefore, is along a wall having a number of windows. This is extremely convenient also from the view of power transmission, and gives the maximum free floor space to the factory. In setting up machines, foresight must be displayed, otherwise one may find, when future extensions are made, that the extra machines may obstruct an entry or exit. [16] Windows imply the existence of walls. Such is the conventional design of factories. It may be pointed out that walls are not necessary. The roof may be supported on pillars between which expanded metal of large size may be placed. This fulfils all requirements and gives the maximum of light and air. Many new factories have been erected to such a design.