TO CHANGE FROM TWADDLE SCALE TO SPE CIFIC GRAVITY, OR FROM GRAVITY TO TWADDLE SCALE. In order to change degrees Twaddle into specific gravity, multiply by 5, add 1000, and divide by 1000. Example: Change 168° Twaddle into specific gravity. 168 X 840 1,000 1,000) 1.840 1.84 Spec. Grav. To change specific gravity into degrees Twaddle, multiply by 1000, subtract 1000, and divide by 5. Example: Change 1.84 specific gravity into degrees Twaddle. 1.84 X 1,000 1,840 1,000 5) 840 168° Tw. The degrees of Twaddle's hydrometer are easily turned into specific gravity numbers-a quality which makes it preferable to any other hydrometer in use. The rule is to multiply the indicated degree by 5, and add 1000 to the product; for example, 9 degrees Twaddle equals specific gravity 1045; 25 degrees Twaddle equals specific gravity 1125; 100 degrees Twaddle equals specific gravity 1500; and so on. To bring specific gravity numbers to degrees of Twaddle, subtract 1000, and divide the remainder by 5; for example: specific gravity 1000 degrees equals 20 degrees Twaddle. If the sample is too viscous to determine the density directly, a weighed portion of it can be first diluted with a weighed quantity of water, or a weighed portion can be dissolved and diluted to a known volume with water. In the first instance the per cent. of total solids is to be calculated by the following formula: WS Per cent. of solids in the undiluted material S per cent. of solids in the diluted material. = W= weight of the sample taken for dilution. W If the dilution was made to a definite volume, the following formula is to be used: Per cent. of solids in the undiluted material = V volume of the diluted solution. D S W = specific gravity of the diluted solution. weight of the sample taken for dilution. To reduce a liquid to a desired specific gravity: Let v equal the volume of the first liquid. Let B equal the Beaumé of the first liquid. VDS W Let b equal the Beaumé of the second or reducing liquid. Let a equal the Beaumé required. Let z equal the volume of the reducing liquid. av-vB z= b-a SULPHURIC ACID. The Manufacturing Chemists' Association have adopted the following figures as representing the per cent. of H„SO, in an oil of vitriol. Since colorists rarely or never need to look up an acid |