Fahrenheit scale

“ The only way to compare the proportional temperatures of bodies, whether on the earth or in space, is therefore by means of a scale beginning at this natural zero, instead of those scales founded on the artificial zero of the freezing point of water, or, as in Fahrenheit's, 32° below it. Only by using the natural zero and measuring continuously from it can we estimate temperatures in relative proportion to the amount of heat received. ”

“ The string must be attached, of course, to the top of the thermometer scale.
When travelling on the Continent it is sometimes desirable to be able to read the thermometers which are graduated in a different manner to that of Fahrenheit. In France the Centigrade scale is preferred, and in many parts of Germany Reaumur's graduation. The difference of the graduation is seen at a glance.
The number of degrees, therefore, between boiling and freezing is 100 in the Centigrade, 80 in Reaumur, and (212-32, that is) 180 in Fahrenheit. ”

“ In the Réaumur scale, still largely used in Russia and Germany, the freezing-point is marked zero, and the space between this and boiling-point is divided into 80 degrees. To reduce it to Fahrenheit, multiply by 21⁄4 and add 32; to Centigrade, increase the number by one-fourth of itself. Thus: F = 9⁄5 C + 32 = 9⁄4 R + 32; C = 5⁄9 (F - 32) = 5⁄4 R; R = 4⁄9 (F - 32) = 4⁄5 C.—Maximum thermometer, one that registers the maximum temperature to which it is exposed; Minimum thermometer, one that registers the minimum temperature to which it is exposed. [Gr. thermē, heat, metron, a measure.] ”

“ The Absolute scale, long familiar to physicists, has recently come into somewhat limited use in meteorology. It starts at the “absolute zero”—the temperature of a body totally devoid of heat. This temperature has been nearly attained in laboratory experiments with liquid helium. One advantage that the Absolute scale possesses over the others is that it has no below-zero readings. Such readings are a source of occasional errors when temperature is recorded on the Fahrenheit or the Centigrade scale. ”

“ The Florentine thermometers had one fixed point, that of freezing water, and contained either spirits or mercury. In 1724 Fahrenheit, in Danzig, fixed three points on the scale of the mercurial thermometer, viz. the cold produced by ice and sal-ammoniac which he called 0°, freezing water or 32°, and the heat of the human blood which he assumed to be 96°. This thermometric scale, having 180° between freezing and boiling water, and that of Celsius, with 100°, are the only ones in scientific use to-day. ”

“ The central heat of our globe is a reality that cannot be disputed, and after digging beyond a depth of twenty feet the thermometer gradually rises at the rate of one degree of Fahrenheit's scale for every fifteen yards. ”

“ For the most part he lived in England and Holland, devoting himself to the study of physics and making a living, apparently, by the manufacture of meteorological instruments. He was the author of important improvements in the construction of thermometers, and he introduced the thermometric scale known by his name and still extensively used in Great Britain and the United States (see Thermometry) . ”

“ The lower section contains the trace of the barometer, the horizontal lines being the heights in [Pg_148] metres and feet that correspond to the barometric pressure with a temperature of 32° Fahrenheit; in the middle section is the trace of the hygrometer on a scale of relative humidity in percentages, and in the upper section is the trace of the thermometer on a scale of temperatures in Fahrenheit and Centigrade degrees. ”

“ Whenever the thermometer is mentioned, it is to be understood of a large mercurial one, graduated according to Fahrenheit's scale, kept in a proper place within doors (either in a wooden building or a thatched hut, with a southern aspect) except when I describe the sun rays, the intensity of which was measured by a smaller instrument of the same kind, hung out of doors, at some distance from the walls of the houses ”

“ Fahrenheit is given credit for the discovery that water freezes always at the same temperature. With these facts he devised a scale for thermometers in 1714.
THERMOMETER RECORDS A temperature of 111° below zero has been recorded at an altitude of 48,700 feet in the United States.
The highest record in the United States Weather Bureau was taken in Death Valley, Cal., on June 30, July 1 and 2, 1891, when the thermometer reached 122° F. Death Valley is also given credit for the highest known monthly temperature, which was 102° F. in the month of July. ”

“ The thermometer (I have made some observations) falls in winter to 4 degrees Centigrade at the outside, which gives us 24 degrees Reaumur as the maximum, or otherwise 54 degrees Fahrenheit (English scale) , not more. And, as a matter of fact, we are sheltered from the north winds by the forest of Argueil on the one side, from the west winds by the St. ”

“ Explain the heaving of oats, clover, wheat.
6. Do all liquids expand on freezing? Try melted paraffin.
THE THERMOMETER
Besides the ordinary thermometer the school should possess a chemical thermometer graduated from 0° Fahrenheit to 212°.
1. Our sensations vary so much under different circumstances and in different individuals that they cannot be depended on. Find examples of this and show the need of a measuring instrument.
2. The pupils can learn, by examination of the common wall instrument, the parts of the thermometer—tube, bulb, liquid (alcohol or mercury) , and scale. ”

“ In the course of more than half a century the temperature of the earth at the depth of 90 feet, in the cellars of the Observatory at Paris, has never been above or below 53° of Fahrenheit’s thermometer, which is only 2° above the mean annual temperature at Paris. This zone, unaffected by the sun’s rays from above, or by the internal heat from below, serves as an origin whence the effects of the external heat are estimated on one side, and the internal temperature of the globe on the other. ”

“ The reason why temperature diminishes as we ascend, is partly owing to the greater loss of heat by radiation through the thinner envelope of the upper strata, and partly owing to the greater absorption of the heat given off from the earth by the lower and denser strata. In general, it may be said that there is a diminution of 1° Fahrenheit for each three hundred and thirty feet that we rise vertically, but, this rate varies greatly at different heights, places, and times. ”

“ It is now known that this is an arbitrary point, far above the lowest temperature in the polar regions and several hundred degrees above the greatest cold produced by artificial methods. In the Reaumer thermometer, generally used in Germany, and the Centigrade thermometer, commonly used in France and by scientists of all nations, zero marks the freezing point of distilled water at the sea level, or under an atmospheric pressure of 14.73 pounds to the square inch. To reduce Fahrenheit to Centigrade, subtract 32 and multiply by 100/180, or 5/9. ”

“ Governor Ellis in the year 1758 had observed, that a man could live in air of a greater heat than that of his body; and that the body, in this situation, continues its own cold; and the abbé Chappe d’Auteroche had written that the Russians used their baths heated to 60 deg. of Reaumur’s thermometer, about 160 of Fahrenheit’s. With a view to add further evidence to these extraordinary facts, and to ascertain the real effects of such great degrees of heat on the human body, Dr. Fordyce tried various experiments in heated chambers without chimneys, and from whence the external air was excluded. ”

“ It is obviously and utterly impossible that in addition to the ordinary accumulation of heat at the surface of the earth “as the day advanced”—that is, during the forenoon, warm currents should ascend, unobserved by Gay-Lussac during an ascent of 12,000 feet—not affecting in the least so large an intervening body of the atmosphere or his thermometer, and in such immense volumes as to increase the warmth of a stratum of 4,000 feet in depth, an average of 3° of Fahrenheit, and to the extent of 6° at the center. ”

“ When the common rack and manger are preferred, the rack staves should be straight, and brought nearly down to the manger, and this may easily be done without the necessity of a hay loft, and the manger may be made deep and wide as I have described it.
The heat of a stable should be graduated by a thermometer, always kept there for the purpose. Our feelings are but a feeble guide to our judgment in measuring temperature. It would be well that the stable heat should seldom reach, but never exceed, 50 degrees of Fahrenheit in winter, or 65 in summer. ”

“ The decrease of the mean heat of the globe during a period of 2000 years has not therefore, taking the extremest limits, diminished as much as 1/306th of a degree of Fahrenheit.42—Humboldt’s Cosmos, vol. i.
NICE MEASUREMENT OF HEAT.
A delicate thermometer, placed on the ground, will be affected by the passage of a single cloud across a clear sky; and if a succession of clouds pass over, with intervals of clear sky between them, such an instrument has been observed to fluctuate accordingly, rising with each passing mass of vapour, and falling again when the radiation becomes unrestrained. ”

“ For example, a piece of ice out of doors is at 10°F. when the air is at this temperature. It follows then, that when ice has been cooled below the freezing [Pg 165] temperature that heat is required to warm the ice up to its melting point; or in other words that ice at its melting temperature possesses some heat. The temperature at which absolutely no heat exists is called absolute zero. There has been devised an absolute scale of temperature. This scale is based upon the centigrade scale, i.e., with 100° between the two fixed points ”

“ After the temperature has attained a maximum, there will be, with a decrease of heat, a slight contraction of mercury in the tube—as well as of that in the bulb—and hence doubts have arisen as to the accuracy of the registration; but calculation shows, and critical trial has proved, that the greatest daily range of temperature will not produce an error large enough to be appreciable on the scale. ”

“ Cotemporary observations, made at Monticello and Williamsburgh, proved the variations in the weight of air to be simultaneous and corresponding in these two places.
Our changes from heat to cold, and cold to heat, are very sudden and great. The mercury in Fahrenheit's thermometer has been known to descend from 92° to 47° in thirteen hours ”

“ It contracts in cooling down to 40 degrees of Fahrenheit’s thermometer; in cooling further it expands, and when cooled to 32 degrees, it freezes. Hence, the greatest density of the fluid is at 40 degrees, and water of this temperature, or near it, will lie at the bottom with cooler water or with ice floating above it. However much the surface be cooled, water colder than 40 cannot descend to displace water warmer than itself. Hence we can never have ice formed at the bottom of deep water. ”

“ When existing instruments are compared with this standard, it is found that a scale based on the assumption that the volume of a gas free to expand, or the pressure of a confined gas, increases directly as the temperature is in close agreement with the thermodynamic scale. ”

“ The slowest decrease? Is there any regularity in these rates of temperature decrease either on one map or in the whole series of maps?
The term temperature gradient is used by meteorologists to describe the direction and rate of temperature decrease which we have been studying.
If we are to compare these rates of temperature change, we must have some definite scale of measurement. Thus, for example, in speaking of the wind velocity we say the velocity of the wind is so many miles per hour; in describing the grade of a railroad we say it is so many feet in a mile. ”

“ Any one who shows over ninety-nine degrees Fahrenheit is examined further for corroborative symptoms. The temperature of every one of the steerage is taken and the glass thermometer is not always cleaned as it is passed from mouth to mouth here in these crowded regions! ”

“ The thermometer runs very high in this country, and it is not at all rare for it to indicate one hundred and twenty-five or one hundred and thirty degrees Fahrenheit. One traveler has a record of one hundred and thirty-nine degrees in the shade and one hundred and seventy-two in the sun. I am told that in South Melbourne the thermometer once made an official record of one hundred and eleven degrees in the shade and one hundred and seventy-nine degrees in the sun. ”

“ At Sennaar, from 70° to 78° in Fahrenheit's thermometer is cool; from 79° to 92° temperate; at 92° begins warm. Although the degree of the thermometer marks a greater heat than is felt by the body of us strangers, it seems to me that the sensations of the natives bear still a less proportion to that degree than ours. On the 2d of August, while I was lying perfectly enervated on a carpet, in a room deluged with water, at twelve o'clock, the thermometer at 116°, I saw several black labourers pulling down a house, working with great vigour, without any symptoms of being at all incommoded. ”

“ Fahrenheit was a manufacturer of all sorts of physical apparatus, and it has been thought probable that he had some special facilities for dividing his thermometer tubes into 180 parts. Mercury is most commonly used as the liquid in thermometers, because it readily indicates changes of temperature, and because over most of the world the winter cold is not sufficient to freeze it. ”