There are three different thermometers in use - Fahrenheit's, Centigrade and Reaumur's - each differing from the other with reference to the number of degrees between the freezing and boiling points of water. In Fahrenheit's, zero is placed at 32 degrees below the freezing point, while in the others zero marks the freezing point.

The boiling point in Fahrenheit's is placed at 202 degrees; in Centigrade at 100, and in Reaumur's at 80.

The degrees between the freezing and boiling points in the instruments are, therefore, respectively 180, 100 and 80.

The following diagram will explain the variance: -

Fahrenheit

.......0.

32

77

122

167

212

Centigrade

.......17.77

0

25

50

75

100

Reaumur

.........................14.22

0

20

40

60

80

When a thermometer, in the process of vulcanizing, gives trouble by the column of mercury becoming divided, the divided portion remaining in the top of the tube, the best method is to unscrew the thermometer and turn it upside down, and make the mercury in the bulb unite with the mercury in the tube, so that it may coalesce perfectly. This is a better method than striking the thermometer sharply in the hollow of the left hand, and thereby risking the breaking of the thin glass tube.

Temperature

The Clinical Thermometer is employed as a valuable means of diagnosis and prognosis. It is valued because the vital processes can only be normally and perfectly performed at the temperature of 98.50, and just in proportion as it varies from this, either above or below, they are changed or entirely arrested. This standard of temperature, 98.50, of the healthy body, is subject to slight variations during the day. A temperature of 1050 is usually considered dangerous and 1070 is generally fatal; any rise above the normal indicates fever, and a decrease indicates shock or collapse. Although observations show that the normal heat, which is the most essential condition of life, may be considerably altered by a number of circumstances, yet the variations in health are generally temporary and within narrow limits, whereas those which arise from disease are persistent during the continuance of the abnormal condition. Both increase and decrease of temperature have to be considered, for while an increase of four to six degrees may be maintained for a month, and not endanger life, a decrease of but one degree, if maintained for a considerable time, will result in death. The temperature in fevers is highest in the evening and lowest in the morning. But in the fever resulting from difficult dentition the temperature is highest in the morning and lowest in the evening. The increase in temperature of the body is usually proportionate to the frequency of the pulse, one degree corresponding to an increase of ten beats per minute. Thus -

With a temperature of 980, we have a pulsation of 60.

"

"

99°.

"

"

70.

"

"

1000,

"

"

80.

"

"

1010,

"

"

90.

"

"

1020,

"

"

100.

"

"

1030,

"

"

110.

"

"

1040,

"

"

120.