Since the meter can only register when water is passing
through, should the hands move wlien all outlets are closed,
water is l>einR wasted tbrough some leak. This can be most
easily detected by oliserving the cirele marked **one foot/* re-
ferred to above as being provided for purposes of test.
DENSITY OP LIQUIDS
A knowicdge of the density or specific gravity of a liquid is
usually of vahie in the household only as an index of some other
physical property or quality of the liquid. For example, in the
preparation of sirups, jellies, and other food products of similar
nature^ a measurement of specific gravity is a eonveiiicnt means
of determining when the process of evaporation or ** boiling
down'* has been carried far enough. Also, the quality or fat-
content of milk may be detennined by measuring its specific
gravity.
Specific gravity is the ratio of the weight of any volume of a
substance to the weight of an equal volume of w^atcr. Milk has
a specific gravity of 1.03, since the weight of any volume of
milk is 3 per cent more than that of an equal volume of water.
The densities given in Table IV are stated in grams to the cubic
centimeter, and are numerically the same as specific gravity in
terms of water at 4° C. as unity.
Determination of speeific grainty.
The specific gravity of a hquitl may be most readily deter-
mined l)y means of a small glass instrument known as the hy-
drometer. This instrument floats in the liquid to be examined
and the specific gravity of the liquid is determined by noting the
154
A MANUAL OF HOME-MAKING
point on the stem to which the instrument sinks in the liquid. !
Since a floating body ^^i^k8 in a liquid to such a point that the
weight of the liquid displaced by the body is equal to the weight
of the body, the hydrometer, when provided with a suitable
8cale» indicates directly the specific giavity of the liquid.
Classes of hydrometers,
Hydrometei-s in general use may be divided into three claasea
with reference to their indication: 1. Specific gravity hydrom-*
eters; 2. per cent hydrometers; 3. arbitrary' scale hydrometers.
Specific gravity hydrometers indicate the ratio of the weight
of a given volume of the substance to the weight of the same vol-
ume of some standaici substance. The standard sii Instance is
umjally water at a tiefiuite temperatute.
Per cent hydroiiiefcrs indicate the percentage of a substance,
either by weight, or Ijv vohitne, in a mixture or solution of the
substance in water.
Arbitrary scale h^Tlrometers indicate the concentration or
strength of a substance in tenns of some arbitrarily defined scale.
Lactometers and Baum^5 hydrometers are examples of this class.
TABLE IV. — DENfliTiEs op Somk Household Materials
I
Sub$iance
Air, dry .
Air (of 50 per cfint humidity)
Brine (5 parts by weight of salt m 100 parts of
of brine) ......,* _ . . _ ,
Brinr- {25 parts by weight of salt in 100 part?
brine)
Butter
CiiJfT vinegar
Cream * (18 per cent butter fat)
Cream (40 per cent butter fat)
riasnliiio
Tempera-
ture in
degrees
centigrade
20 m*
20
15
15
20
20
20
Denjfity in h
Qrams U^ the H
o.ooiaoifl
o.ooi:
o.oouds
1.035
1.191
0 86 to 0,87
1 0!3 to 1,015
1 01
0 99
n 70 to 0,74
* Minimum buttx^fat content for cream (defitiition of Bureau
ietry).
hoVSEHOLb ^tSASVRE^fENTS AND THEIR USE 155
TABLE IV.— Coii/inuerf
Tevipera-
Deji&ity in
Page 87
Presented as published in 1919. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
A modernized reading is not available for this page yet. You are seeing the original text.
Since the meter can only register when water is passing
through, should the hands move wlien all outlets are closed,
water is l>einR wasted tbrough some leak. This can be most
easily detected by oliserving the cirele marked **one foot/* re-
ferred to above as being provided for purposes of test.
DENSITY OP LIQUIDS
A knowicdge of the density or specific gravity of a liquid is
usually of vahie in the household only as an index of some other
physical property or quality of the liquid. For example, in the
preparation of sirups, jellies, and other food products of similar
nature^ a measurement of specific gravity is a eonveiiicnt means
of determining when the process of evaporation or ** boiling
down'* has been carried far enough. Also, the quality or fat-
content of milk may be detennined by measuring its specific
gravity.
Specific gravity is the ratio of the weight of any volume of a
substance to the weight of an equal volume of w^atcr. Milk has
a specific gravity of 1.03, since the weight of any volume of
milk is 3 per cent more than that of an equal volume of water.
The densities given in Table IV are stated in grams to the cubic
centimeter, and are numerically the same as specific gravity in
terms of water at 4° C. as unity.
Determination of speeific grainty.
The specific gravity of a hquitl may be most readily deter-
mined l)y means of a small glass instrument known as the hy-
drometer. This instrument floats in the liquid to be examined
and the specific gravity of the liquid is determined by noting the
154
A MANUAL OF HOME-MAKING
point on the stem to which the instrument sinks in the liquid. !
Since a floating body ^^i^k8 in a liquid to such a point that the
weight of the liquid displaced by the body is equal to the weight
of the body, the hydrometer, when provided with a suitable
8cale» indicates directly the specific giavity of the liquid.
Classes of hydrometers,
Hydrometei-s in general use may be divided into three claasea
with reference to their indication: 1. Specific gravity hydrom-*
eters; 2. per cent hydrometers; 3. arbitrary' scale hydrometers.
Specific gravity hydrometers indicate the ratio of the weight
of a given volume of the substance to the weight of the same vol-
ume of some standaici substance. The standard sii Instance is
umjally water at a tiefiuite temperatute.
Per cent hydroiiiefcrs indicate the percentage of a substance,
either by weight, or Ijv vohitne, in a mixture or solution of the
substance in water.
Arbitrary scale h^Tlrometers indicate the concentration or
strength of a substance in tenns of some arbitrarily defined scale.
Lactometers and Baum^5 hydrometers are examples of this class.
TABLE IV. — DENfliTiEs op Somk Household Materials
I
Sub$iance
Air, dry .
Air (of 50 per cfint humidity)
Brine (5 parts by weight of salt m 100 parts of
of brine) ......,* _ . . _ ,
Brinr- {25 parts by weight of salt in 100 part?
brine)
Butter
CiiJfT vinegar
Cream * (18 per cent butter fat)
Cream (40 per cent butter fat)
riasnliiio
Tempera-
ture in
degrees
centigrade
20 m*
20
15
15
20
20
20
Denjfity in h
Qrams U^ the H
o.ooiaoifl
o.ooi:
o.oouds
1.035
1.191
0 86 to 0,87
1 0!3 to 1,015
1 01
0 99
n 70 to 0,74
* Minimum buttx^fat content for cream (defitiition of Bureau
ietry).
hoVSEHOLb ^tSASVRE^fENTS AND THEIR USE 155
TABLE IV.— Coii/inuerf
Tevipera-
Deji&ity in