A Stalagmometer is an instrument used to determine surface tension using the drop weight or drop number method. Viscosity is measured using viscometers (such as Ostwald viscometer). Specific conductance is measured by a conductivity meter.

Stokes' law states: $v = \frac{2 r^2 (\rho_f - \rho_p) g}{9 \eta}$ (or $\frac{g d^2 (\rho_p - \rho_f)}{18 \eta}$), where $v$ is the creaming velocity, $r$ is radius, $d$ is diameter, $\rho_p$ and $\rho_f$ are densities of plasma and fat, $g$ is acceleration due to gravity, and $\eta$ is the dynamic viscosity of the liquid continuous phase (milk plasma). Thus, velocity $v$ is inversely proportional to the viscosity of plasma ($\eta$).

Specific gravity is calculated from Corrected Lactometer Reading (CLR) by the formula: $\text{Specific Gravity} = 1 + \frac{\text{CLR}}{1000}$. For $\text{CLR} = 28$, $\text{Specific Gravity} = 1 + \frac{28}{1000} = 1.028$.

Physical basis of the Recknagel phenomenon in milk:

• Assertion (A) is true: When freshly drawn milk is cooled and held at refrigeration temperatures, its specific gravity (density) undergoes a slow, continuous increase over several hours (by roughly $0.001\text{ to }0.0015\text{ g/ml}$). This spontaneous rise in observed density on aging at low temperature is classically defined as the Recknagel phenomenon.
• Reason (R) is false: The true scientific mechanism of the Recknagel phenomenon is twofold: (i) the gradual, progressive solid-state crystallization of milk fat globules from liquid to dense crystalline form accompanied by significant volume shrinkage, and (ii) the slow hydration and swelling of casein micelles. It is NOT caused by the loss of entrapped air or gas (gases actually become more soluble at lower temperatures).