Considering that a mixing made from a fixed quantity of certain ingredients is not generally used for percentages ranging more than 15 per cent., and that different mixings are required all the way up to 150 or 200 per cent., whilst at the same time not more than two or three manufacturers may use exactly similar mixings even for the same degree of weighting, it will readily be seen that the mixings employed in the cotton trade are innumerable. This difference has been caused by the jealous care taken by a sizer to preserve to himself the recipe of his own mixing, and rightly so. Thus, new mixings have had to be adopted by new firms, the correct quantity of each ingredient having to be fixed by repeated experiments; and as the true properties of each substance have not been, and are not yet, well understood among manufacturers according to scientific investigation, the differences of opinion, and consequent differences of recipes, are very great. Nor is it to the ingredients that these opinions are confined, but to the order of putting each into the beck, the times of fermenting and boiling, and many other details. It is somewhat difficult to satisfactorily determine beforehand the amount of weight which can be obtained from a mixing. An instrument, really a hydrometer, but often, from the name of its inventor, dubbed a “Twaddle,” is sometimes used; but unless a fixed temperature is always taken, these instruments are not reliable, as a mixing twaddles differently at different heats. Indeed, from the varying results obtained, a twaddle cannot be said to be of much practical use in sizing. A better system, perhaps, is to take the proportion of solid or semi-solid matters in a mixing as against the weight of water, and compare it with the ratio of another mixing which is known to give a certain percentage. Thus, if one mixing of 3lb. of solid matter to a gallon (10lb.) of water gives 25 per cent., then a mixing with 6lb. solids to the gallon may roughly be said to put in 50 per cent. Heavy liquids, such as zinc and solution of magnesium chloride, will have to be reckoned partially as liquids, in consequence of the evaporation which will take place on drying at the cylinders; and the softeners, from their inability to retain liquids as well as the starches, will not be calculated as having the same weighting power. Magnesium may be reckoned as having one-third of its weight in solids, and zinc at one-half. _For Light Sizing._--Taking a pure size, say 8 to 10 per cent., farina and wax or tallow is generally used as being the cheapest, and at the same time most suitable mixing. The ingredients are generally combined in the same beck that they are boiled in; for 10 per cent. the following may be used: 200lb. farina, 20lb. wax, 200 gallons water. By the addition of clay, the same may be made serviceable up to 25 per cent.