On some estates a great deal of the frothing is avoided by placing in position at the receiving end of the tank a perforated partition. This partition may be made of wood, or of stout zinc (or aluminium) carrying ten circular holes to the inch. Through this the latex percolates, while the froth is retained on a small area. The froth is removed prior to the addition of the acid. After stirring in the acid solution most estates again skim the surface of the latex; but if the stirring has been performed properly there should be little froth. This, when it collapses, in any case will appear only on the upper edge of the strip of coagulum, and after rolling should not be visible. It would appear, therefore, that the second skimming is not necessary. STYLE OF SHEET.--Within the last few years the custom of making plain sheet--_i.e._, sheet having a plain surface--has gradually given place to the preparation of ribbed sheet--_i.e._, sheet having a pattern marked on the surface. It would probably be correct to say that plain (smooth) sheet is now only prepared by natives or by some estates just come into bearing. Even in the latter case there is no reason why smooth sheet should be made, as hand machines are sold which will do all the work required. It will be evident to anyone acquainted with rubber preparation that in the matter of actual quality of rubber the question of smoothness or a pattern can have no bearing on the result. One advantage claimed for ribbed sheet which may entirely justify the preference exhibited by consumers, relates to the question of packing. When rubber arrives at home it is frequently found to be in an almost solid block, due to the pressure of the sheets superimposed in the case. The smoother the surfaces of the rubber in contact the greater the adhesion and the denser will be the mass, and consequently the greater the difficulty in separating individual pieces. Under such circumstances it is plain that the difficulty is diminished if the sheets have a raised pattern on them. It is noted also that the liability to mildew-growth is greater the smoother the surfaces of the rubber. On these grounds the "marking" of sheet rubber is to be commended. These reasons apart, it is really astonishing the difference made in the appearance of the sheets by impressing upon them a ribbed pattern, and it is highly probable that the market value of the rubber is slightly increased. It is not our duty to attempt to reason why this simple operation should increase the market value of sheet rubber; it is sufficient to recognise that it is so, and that money may be thrown away by neglecting to cater for the taste of the market. Of the patterns impressed upon sheet rubber there is a variety, but the general style is that known as the "spirally close-cut ribbing."