consuming one pound of beans per day, and taking meat only on "high
days and holidays."

[Illustration: FIG. 26.--The bomb calorimeter from which the fuel
value of food can be estimated.]

The fuel value of a food is determined by means of the _bomb
calorimeter_ (Fig. 26). The food substance is put into a chamber _A_
and ignited, and the heat of the burning substance raises the
temperature of the water in the surrounding vessel. If 1000 grams of
water are in the vessel, and the temperature of the water is raised 2°
C., the number of calories produced by the substance would be 2000,
and the fuel value would be 2000 calories.[A] From this the fuel value
of one quart or one pound of the substance can be determined, and the
food substance will be said to furnish the body with that number of
heat units, providing all of the pound of food were properly digested.

[Footnote A: As applied to food, the calorie is greater than that used
in the ordinary laboratory work, being the amount of heat necessary to
raise the temperature of 1000 grams of water 1° C., rather than 1 gram
1° C.]

TABLE SHOWING THE NUMBER OF CALORIES FURNISHED BY
ONE POUND OF VARIOUS FOODS
----------------------------------------------------
|FOOD |CALORIES|FOOD |CALORIES|
----------------------------------------------------
|Leg of lean mutton | 790|Carrots | 210|
----------------------------------------------------
|Rib of beef | 1150|Lettuce | 90|