[Illustration: A "BATTERY" OF SHEETING TANKS (PATALING ESTATE). DILUTION TANKS, RAISED, ON THE LEFT.] On the other hand, too low a standard also brings trouble in its train. The coagulum is too porous, will not stand handling, and the resultant sheet is too thin unless an abnormal thickness of coagulum is prepared. Furthermore, over-dilution means an increase in the number of tanks required for any original volume of latex. This involves an increase in floor area, and perhaps in the size of the building. The soft sheets, when rolled, may spread to such a width as to cause the edges to be squeezed under the cheek-blocks of the machines, etc. For all practical purposes, whether sheets are prepared in pans or in tanks, it has been found that the optimum results are obtained by the adoption of a standard approximating and not exceeding 1-1/2 lbs. dry rubber per gallon. Primarily this standard has a direct connection and interdependence with the distance between the partitions (or between the slots) in coagulating tanks. The distance found most practicable is 1-1/2 inches. This thickness of coagulum, when prepared from latex not exceeding a standard of 1-1/2 lbs. dry rubber per gallon, is found to yield a very satisfactory sheet in all respects. It will be seen that we have two possible main factors of variation: (_a_) Distance between partitions, causing visible differences in thickness of coagulum. (_b_) Dry rubber content of latex, causing differences in the density (_e.g._, hardness or softness) of the coagulum. The effect of variation in (_a_) will be clear. Even when latex of a standard of 1-1/2 lbs. per gallon is employed the resulting sheet may be either too thin or too thick. Similarly, as already argued, the use of too low or too high a standard of dilution (when the factor of distance between partitions is not allowed to vary) is capable of causing much difficulty. While this is correct, broadly, it is found in the experience of some estates that their requirements are satisfied by a slightly lower standard than 1-1/2 lbs. per gallon. Thus it is not uncommon to note the adoption of a standard equivalent to 1 lb. 4 ozs. or 1 lb. 6 ozs. dry rubber per gallon. Experience dictates, however, that for the recognised standard measurements of modern tanks the practical limits of satisfactory density of latex lie between 1-1/4 lbs. and 1-1/2 lbs. per gallon.