Lactodensimeter

LACTODENSIMETER, a special hydrometer for determining the specific gravity of milk. The instrument was proposed by Quevenne (Fig. 1) and improved by Soxhlet, Müller, Gerber, Bischoff, and others by incorporating a thermometer and making certain modifications to its form. The most rational modification of the instrument is the Quevenne-Müller lactodensimeter (Fig. 2), which consists of a hollow glass body, at the lower end of which there is a heavy mercury ball, and at the upper end a narrow glass tube equipped with a scale with divisions from 14 to 42, corresponding to the specific gravity of milk from 1.014 to 1.042. The tube at the top terminates with a thermometer scale indicating the temperature of the milk during examination. To determine the specific gravity of milk, it is thoroughly mixed, poured into a glass cylinder, and the L. is immersed in it. The division to which the instrument is submerged indicates the specific gravity of the milk; simultaneously, the temperature of the milk is also noted, which should be equal to 15°. If the temperature of the milk is above 15°, then for each degree above 15°, 0.2 should be added to the reading of the L., and if the temperature is below 15°, then for each degree below 15°, 0.2 should be subtracted from the reading of the L. In addition to the divisions indicating the specific gravity of milk, there are also two colored scales on the stem of the L.: yellow for whole milk and blue for skimmed milk. These scales are intended for determining the amount of water added to milk if it, judging by the specific gravity and percentage fat content, has been falsified by dilution with water. Thus, the division to which the L. is submerged in milk indicates on the central scale the specific gravity of the milk, and on the side (colored) scales the degree of dilution of milk with water, if it has been falsified.

N. Ignatov. Lit.—see lit. to art. Lactobutyrometer.