Henry Carrington Bolton

“ I. The Open Air-Thermometer of Galileo.
Discoveries and inventions are sometimes the product of the genius or of the intelligent industry of a single person and leave his hand in a perfect state, as was the case with the barometer invented by Torricelli, but more often the seed of the invention is planted by one, cultivated by others, and the fruit is gathered only after slow growth by some one who ignores the original sower. ”

“ He observed that thermometer stems were not sufficiently even and cylindrical, being often widest near the bulb, and said this was a source of inaccuracy.
Boyle felt the need of a standard permitting comparison of effects shown by different thermometers, and expressed it thus: "We are greatly at a loss for a standard whereby to measure cold. The common instruments show us no more than the relative coldness of the air, but leave us in the dark as to the positive degree thereof; whence we cannot communicate the idea of any such degree to another person. ”

“ Réaumur, who next sought to improve the thermometer, was one of the most popular savants in France; his position in the world of science as well as in that of society, was far more conspicuous than that of the humble artisan Fahrenheit, and his aristocratic station is evidenced by his full name: René Antoine Ferchault, Seigneur de Réaumur, des Angles et de la Bermondière. He early became a member of the French Academy of Sciences, and for more than fifty years assiduously cultivated the sciences ”

“ Heat makes air and water subtle and light; cold, as the opposite of heat, makes them smaller and presses them together and condenses all the air that the heat had made to rise, as may be clearly shown when a glass retort is hung with the mouth in a bucket of water and fire is placed under the belly. We shall then see that as soon as the air in the glass begins to get hot, that air rises out of the mouth of the retort, and the water gets full of bubbles, and this continues so long as the air gets hotter ”

“ In Galileo's extant writings there is only one reference to the thermometer and this corresponds in time with the letters of his friend Sagredo. In this fragment Galileo tries to explain the principle of the thermometer; he says that "when the air in the bulb contracts through cold, the wine in the stem rises to take the place of the void thus formed, and when the air is warmed it is rarefied and takes up more space so that it drives out and presses down the wine; "from this," says Galileo, "it follows that cold is nothing but absence of heat." ”

“ The historians of physics seem to have overlooked another passage of still greater interest which I discovered in the copy of Sanctorius at Washington. Translated it reads thus: "We determine the temperature by means of our glass instrument; we ascertain the high and the low (points) after this manner: we apply snow to the bulb of the glass instrument that the water may ascend to the highest point, then we approach the flame of a candle that the water may descend to the lowest point." ”

“ It would be well to have a universal and determinate standard for heat and cold, securing a definite proportion between the capacity of the bulb and the tube, and then taking for the commencement the degree of cold at which water begins to freeze, or better the temperature of boiling water, so that without sending a thermometer to a distance, one could communicate the degrees of heat or of cold found in experiments and record them for the use of posterity. ”

“ So that whenever observations of a thermometer are made by any curious person to signify the degree of heat in the air or other thing they cannot be understood, unless by those who have by them thermometers of the same make and adjustment. ”

“ Five instruments for measuring heat were described by the academy:
I. The first is described as a long tube having a spherical bulb and closed with "Hermes' seal" at the flame of a lamp. The tube is filled with "spirit of wine up to a certain mark on the neck, so that the simple cold of snow or ice externally applied may not be able to condense it below the 20 degrees of the tube, nor on the contrary the greatest vigor of the sun's rays at midsummer to rarefy it above 80 degrees." ”

“ Nelli in his life of Galileo cites the following passage: "At last we have among us an instrument by which with a bulb we measure the withdrawal of heat from all the external parts of the body and of the air; by which we discover, very surely, how much more or how much less, daily, we differ from the normal [temperature] ." ”

“ Nothing can illustrate more cogently the imperfections of the best instruments then in scientific hands, and the character of those in ordinary use can be imagined; nothing can better demonstrate the immense advance made by Fahrenheit, and even those who deprecate the wide use of his illogical scale must pay tribute to the value of his services in developing reliable thermometers. ”

“ Of this the "Saggi" say: "We can lay down no certain rule to make it practice, often trials being the only way to effect it; by increasing and diminishing the size of the bulb or the bore of the cane, or the quality of the liquor, till at length it hits it right."
IV. The fourth thermometer had a very long tube bent in the form of a spiral, made "rather for fancy and curiosity to see the liquor run the decimals of degrees by the only impulse of a warm breath than for any accurate deduction." This instrument is styled a "very ticklish thermometer." ”

“ I do not think, however, that the degrees named will ever be exceeded in any fever.
"The scales of such thermometers as are used for determining the boiling-points of liquids begin also at 0° and run up to 600°, for at about this temperature mercury begins to boil. To increase the sensitiveness of thermometers they are made with cylinders instead of spheres, so that a larger surface will be more quickly affected."
Fahrenheit then gives a full account of his method of filling thermometers with liquids, a practical feature not necessary to detail in this place. ”

“ It is still more sensitive if one warms the bulb with his breath, as if one wished to speak a word into its ear to command the water to descend.
"The reason of this motion is that the air heated in the tube rarefies and dilates and wishes to have more room, and therefore presses upon the water and makes it descend. ”

“ Thermometers for a special and limited use were manufactured about 1727 by John Fowler, Swithin's alley, near the Royal Exchange, London; these were adapted to the cultivation of hot-house plants, being graduated to indicate degrees most "kindly" to given plants. The instruments varied in length from 18 inches to 4 feet, and the stems were marked from freezing-point of water to 90° a temperature equal to that of warm water capable of being endured by the hand held still, certainly a very vague standard but perhaps sufficiently accurate for vegetable life. ”

“ Dalencé describes the Italian thermoscope as having a bulb the size of a pigeon egg and a tube as big as a quill pen; he suggests the use of a mixture of three parts of water with one of aqua fortis to prevent the liquid freezing, and a flattened bulb to permit heat, or cold, more readily to penetrate the centre of the liquid. ”

“ Again, the origin of a prime invention is sometimes obscured by the failure of the discoverer to claim definitely the product of his inspiration owing to the fact that he himself failed to appreciate its high importance and its utility. The task of sketching the origin of the thermometer is fraught with similar difficulties ”

“ Amontons constructed the first veritable air-thermometer which was not at the same time a barometer; it consisted of a narrow glass tube four feet long, open above, ending below in a large bulb connected by a U-shaped bend; in this bulb air was confined by a column of mercury so adjusted that when the apparatus was immersed in boiling water, the barometer standing at 28 inches, the mercury in the tube stood 45 inches above the level in the bulb, thus making the pressure of the heated air 73 inches. ”

“ The Jesuit Franciscus de Lanis, in a work dated 1670, named Fludd as the original inventor, and Clemente, in his life of Galileo, 1793, has the contemptible effrontery to claim that Galileo in 1603 used an instrument made by Fludd. The facts are that about the year 1603 Fludd visited many countries of Europe, including Italy, where he may well have seen the Galileo thermoscope known to savants in Padua. ”

“ From this experiment and computation Newton drew up the following scale of degrees of heat.
Biot, commenting on Newton's paper, notes that it contains three important discoveries: (1) a method of making thermometers comparable by determining the extreme terms of their graduation from the phenomena of constant temperature; (2) the determination of the law of cooling in solid bodies at moderate temperatures; (3) observation of the constancy of temperature in fusion and ebullition. ”

“ Shortly after Réaumur's publication Joseph Nicolas de l'Isle, professor of astronomy in St. Petersburg, devised a thermometer on the same principles, but adopted as the point of departure the temperature of boiling water, calling it zero, and adjusting the scale so that the freezing-point of water equaled 150 degrees. ”

“ To make use of it, I put it in the sun, and sometimes in the hands of a fever patient, having filled it quite full of water except the neck; the heat expanding the water makes it ascend by a greater or less amount according to the great or little heat."
This evidently describes a water thermometer, or thermoscope, and so far embodied a new principle, yet it was still influenced by the pressure of the air. The instrument did not attract much attention. ”

“ The third point is at 96°; the alcohol expands to this height when the thermometer is placed in the mouth, or the arm-pit, of a healthy man and held there until it acquires the temperature of the body. If, however, the temperature of a person suffering from fever, or some other disease, is to be taken another thermometer must be used having a scale lengthened to 128° or 132°. Whether these degrees are high enough for the hottest fevers I have not examined ”

“ Surely that winter was remarkably mild in frozen Iceland, for zero is often exceeded in countries not regarded as arctic; yet Boerhaave remarks that "nature never produced a cold beyond zero." The Meteorological Yearbook for Denmark shows that the temperature fell in March 1888, at Stykkisholm, Iceland, to −8.5° F.
There is another element of uncertainty in Fahrenheit's scale. Both Musschenbroek and Boerhaave state that the bulb of Fahrenheit's thermometer contains 11,124 parts of mercury at zero and that when the bulb is placed in melting ice the metal expands 32 of these parts ”

“ Christian Huyghens, in 1665, and Dalencé, in 1668, are also credited with the invention of mercury thermometers. In the same year that Dalencé's book appeared, Edmund Halley, the eminent English mathematician and astronomer, was studying experimentally the relative expansion of water, alcohol and mercury, and he stated that mercury would make a good thermometrical liquid if its coefficient of expansion was greater ”

“ In studying the origin and tracing the history of certain discoveries of scientific and practical value one is often perplexed by encountering several claimants for priority, this is partly due to the circumstance that "coincidence of independent thought is often the cause of two or more persons reaching the same result" about the same time; and partly to the effort of each nation to secure for its own people credit and renown. ”

“ His apparatus resembled closely Galileo's, being a glass globe attached to a long narrow tube partially filled with water, which stood in a small open vessel of water; when the air in the globe is warmed the water in the tube sinks, and on cooling it rises. ”

“ The instrument figured in Fludd's book represents the usual inverted air thermoscope in a basin of water, the stem being divided into fourteen degrees, of which seven are below and seven above a central line named "sphaera aequalitis," a curious forerunner of our modern zero with plus and minus degrees. ”

“ I have now completed the task undertaken, viz., to sketch impartially the history of the evolution of the thermometer from its first beginnings in Italy, through its crude early forms down to the three standards now commonly used in all civilized lands. It is interesting to note: First, that no nation makes popular use of the thermometer designed by its own citizen. ”

“ And yet it is easy to show that the Hollander had no part in the invention and never claimed it, and that the error originated in the misinterpretation of a simple experiment described by Drebbel in a treatise on the "Elements."
Cornelius Drebbel, born in Alkmaar, Holland, 1572, was as alchemist who claimed to have discovered perpetual motion, and acquired sufficient reputation for learning to be invited to the court of James II, King of England ”