FoodNet

A manual of home-making

1919

Page 88

Presented as published in 1919. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
ture in grams to the Sid)ntame degrees cubic centv- | cenligrade nuUer ^ Ice , 0,92 Kerosc'tic. . . 2(1 0 78 to 0.82 Lard..... 0,92 Linseed oil . 20 0,92 to 0,93 Milk 20 1.028 to 1.032 Olive oil 20 0 91 Sea water . 15 1 023 to 1.025 Sirup, maplt* 17.5 1 32 to 1.34 Tiillow. 0.91 to 0.97 TurpentiDe . 20 0 86 to 0.87 * The deneity of maple sirup varies from L32 with 35 per cent of writer to 1.34 with 32 per cent of A'ater. The hydrometer to be chosen for household use will depend on the purpose for w^hich it is intended, the degree of accuracy required, and to some extent on the personal preference of the user. The specific gravity hydrometer is recommended for most purposes. For use in making simps, preserves, and the like, an instru- ment indicating specific gravity in tenns of water at 60° F., or one reading in Baom^ degrees will lie fo«nd convenient. The hydrometer should have a range of about 1.00 to 1.50 in specific gravity or 1 to 50 in Baum^ degrees, and should be so graduated that the readings can be conveniently made. Use of the kijdromeier. In using the hydrometer, a portion of the liquid whose specific gravity is to be measured should be placed in a glass cylinder of such a size that the hydrometer when placed in the cylinder will be free to move up and down without coming in contact with the walls of the vessel. The liquid should be well stirred. For specially accurate work, the temperature of the liquid should be observ^ed by means of a thermometer placed directly io the hquid ; when the temper- mm J ise A MANUAL OF HOME-MAKING 4 ature has become fairly constant, the readnigs on the hydrom- eter may be taken. The eye should be placed on a level with the surface of the liquid and the line where this surface appears to cut the stem of the hydrometer should 1x3 taken a-s the i-eading of the hy- drometer. In ca*se the liquid is not sufficiently transparent to allow the scale of file hydrometer to i>e read through tlie liquid, the read- ing cannot be made as indicated almve. It is then necessary to read as accurately as possible a!>ove the surface of the liquid. If the readiop:8 in a dark-colored liquid are always marie in the same way, the resulting error will not be great, and successive readings will be comparable. Influence of tempe}'Qture. When the temperature of a liquid changes^ its specific gravity also changes and the indication of a hydrometer in the liquid will, therefore, differ at different temf^erat ures. All hydrometers should \m marked with the temperature at wiiich they are intended to lie correct. In actual practice, however, it is not always necessary that the hydrometer be used at its standard temperature, but if readings are to be compared, they must all Ije made at the same temperature. For example, it may be found by exiwrience that a certain sirup has the proper consistency wlien cool, if the read- ing on the hydrometer is 1 .36 at WP F. The standaril tempera* ture of the instrument may be GO^ F., but if experience has shown that a certain reading of the hydrometer at some other temperature gives satisfactory results, it is not necessary to wait for the liquid to cool to the standard temperature of the instrument. KITCHEN MEAStHES