Vintage Brochure - The Barometer and Thermometer - 1923

The Barometer

Next to the mariner's compass and chart, the barometer is the most important aid to navigation ever invented. Many persons know that a barometer is an instrument for recording changes in the weather, and the student of physics is taught that this is done by measuring the weight or pressure of the atmosphere.

A rising barometer denotes the approach of good weather; a falling barometer, the reverse. A sudden fall warns the mariner to be on the lookout for a severe storm. The barometer was invented during the Seventeenth Century by Torricelli.

The ship's barometer, which is kept in the chart room, is very different from the original device. It traces a barometric chart, recording the atmospheric pressure throughout the voyage.

Reading the Thermometer

Except in England, the Fahrenheit scale is seldom used in Europe in reading the thermometer. On the continent the Centigrade and the Réaumur are followed in various countries.

To convert Centigrade into Fahrenheit, subtract ten degrees from the given temperature, subtract from the remainder one-tenth of itself, double the last remainder, and add fifty degrees to the product.

To change Réaumur into Fahrenheit multiply by nine, divide by four, and add 32.

 

The following scale will show the main equivalents:

Réaumur	Fahrenheit	Centigrade
32	104	40
19	76	34
10	55	13
0	32	0
-4	23	-5
-14	0	-18