Since a given amount of milk sugar increases the density of a milk more than the same quantity of casein, it is evident that the formula would not apply to those instances in which the ratio between these two ingredients is greatly disturbed, as for instance, the whey.
The formula of Hehner and Richmond, in its latest form, is expressed as follows:
| T = 0.2625 | G | + 1.2F, |
| D |
in which T represents the total solids, G the reading of the quévenne lactometer, D the specific gravity, and F the fat.
Example.—Let the reading of the lactometer be 31, corresponding to D 1.031, and the percentage of fat be three and five-tenths, what is the percentage of the total solids?
Substituting these values in the formulas we have
| T = 0.2625 | 31 | + 1.2 × 3.5 = 12.09. |
| 1.031 |
To simplify the calculations, Richmond’s formula may be written
| T = | G | + | 6F | + 0.14. |
| 4 | 5 |
Calculated by this shortened formula from the above data T = 12.09, the same as given in the larger formula.