Twaddell hydrometer

Twaddell Hydrometer. This hydrometer, which is used only for liquids heavier than water, has a scale such that when the reading is multiplied by 5 and added to 1000 the resulting number is the specific gravity with reference to water as 1000. To convert specific gravity at 60°/60°F to Twaddell degrees, take the decimal portion of the specific gravity value and multiply it by 200 thus a specific gravity of 1.032 = 0.032 X 200 = 6.4° Tw. See also special table for conversion to density and Baume scale. 

Twaddell Hydrometer n Form of technical hydrometer used for measuring the specific gravity of liquids. It does not give a direct reading, but the specific gravity is calculated from the following simple equation ... 

This table gives the relation between density (c.g.s.) and degrees on the Baume and Twaddell scales. The Twaddell scale is never used for densities less than unity. See also Sec. 2.1.2.1, Hydrometers. 

In this table there is opposite a list of different densities, the quantity of dry acid per oent., either diy or monohydrated. To bring the degrees of T Waddell s hydrometer to those of the real specific gravity, it is only necessary to multiply the first by five, and add one thousand thus, supposiug a sample of vitriol to stand t50° on TWaddell s hydrometer, multiply this 150° by 5s, and one has 750° to this add 1000°, and the specific gravity 1 750° is obtained. Now, to ascertain the amount of real sulphuric acid in this sample, it is only necessary to run through the table and hud the density 1-750°, or the nearest approach to it which in this ease is 1 746°, It will be found then that the sample would contain eiglity-three per cent, of the monohydrated acid, or 67 68 per cent, of dry acid. 

Twaddell s hydrometer is used in England for liquids heavier than water. Its degrees are converted into speoi fio gravities by multiplying them by 5, adding 1,000, and dividing the sum by 1,000, Thus —... 

Close examination of these equations, shows that accurate calibration of the hydrometer with several different liquids allows a precise graduation of the immersed height directly in specific gravity units, or hydrometer scales (e.g., Baum, Twaddell, API, etc.). 

This is a hydrometer used for meeisuring density (specific gravity) of industrial liquids which are greater than one. Measures of specific gravity between 1 and 2 are divided into 200 equal parts, and each division is 1 degree. The specific gravity of a solution equals the number of degrees on the Twaddell scale multiplied by 5 and divided by 1,000. The Twaddell is named for its inventor. 

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