Title: Manufacturer and builder / Volume 2, Issue 7

Publisher: Western and Company

Publication Date: July 1870

City: New York

Pages: 386 page images in vol.

Who Invented the Thermometer?

The invention of the thermometer is generally ascribed to the Dutch philosopher Cornelius Drebbel, who was born at Alkmar, in Holland, in 1572, and died in London in 1634. According to a description given by Dalencé, in his Traité des Baromètres, Thermomètres et Notiomètres, (Amsterdam, 1688) it consisted essentially of a glass tube, having a bulb A blown on one end and being open at the other. With the open end it was immersed vertically into a reservoir B, which was filled either with water or a solution of copper in aqua fortis. The air in the bulb A was subjected to the influence of heat, until the liquid ascended to about the middle of the tube H. The variations of temperature, which, of course, would make themselves apparent either by a rise or fall of the liquid column, were indicated upon an arbitrary scale affixed to the tube. History informs us that Drebbel was held in high esteem at the various courts of Europe. His scientific attainments procured him the favor of the most potent rulers of Europe. He presented to Jacob I., of England, a glass ball in which, it is stated, “the perpetuum mobile was carried out by the aid of the four elements.” We read, also, that he could imitate rain, thunder, and lightning, produce an intense cold, and dry up a fountain in an instant. This wonderful man was once, also, considered the inventor of the telescope and microscope; it is, however, now proved that they were not his work, and it will be seen that his claims in regard to the invention of the thermometer are perhaps questionable. Drebbel has written several essays on subjects of natural philosophy, which were first published in Dutch, and subsequently in Latin. A German translation appeared in Erfurt, in 1624, three years after the Latin translation, and a French one in Paris, in 1672. In none of these, however, is the least description of any instrument for the measurement of temperature to be found, which must appear strange, as a great number of experiments conducted by him are related in a somewhat circumstantial manner. All that could lead, at first sight, to look upon him as the inventor of the thermometer is the following sentence:

“If water,” he says, “is heated in a retort, winds will be seen escaping through the orifice, which will ascend as bubbles through the water in the reservoir. If the fire is withdrawn, so that the retort can cool off the water in the reservoir will ascend into it with such a vehemence that it breaks, if of glass.”

Undoubtedly, the apparatus described here presents some similarity to the one illustrated by Dalencé, but it must be noticed that this experiment served to Drebbel merely to explain the morning and evening winds, of which he remarks that they originated by the differences of temperature that are observable between sea and land. Libri, the author of the History of the Mathematical Sciences in Italy, claims the priority of the invention for Galileo. “This great philosopher,” are his words, “having observed that the air expands by heat and contracts by cold, invented a very simple instrument, designed to indicate the changes of temperature.” After describing an instrument like that of which an illustration is given above, he states that Galileo, in 1603, showed such a one to Father Castelli, and that Sagredo, in Venice, in a letter dated 1613, gives an account of observations conducted with the same. —Yet Libri asserts himself, that the works of Galileo contain no description of an apparatus for measuring temperatures, and as published documents are the only decisive proofs in a case like this, the claims for Galileo must also be withdrawn.

The “vitrum calendare,” described by Francis Bacon, in 1619, in his Novum Organum, is a thermoscope, like the former. Bacon neither mentions the name of the inventor, nor does he assign it to himself.

Sanctorius mentions, in his collected works, (Venice, 1660) an instrument invented by him, about 1600, by which the temperature of the human body could be determined. Still, no description of the same is given. It is well known that the first thermometers were filled with water, which, however, was soon replaced by a solution of copper in nitric acid. The construction also was changed. The one as here illustrated originated with Wolf. Subsequently the copper solution was replaced by spirits of wine by the Florentine academicians. It was taken of such a strength that it would explode gunpowder when inflamed. They divided the instrument arbitrarily, as before. The first employment of mercury in thermometers, according to Gehler, took place in the year 1714, (B. Silliman gives the year 1720,) and is probably due to Fahrenheit. However, the writer of this ventures to express the opinion that the same must have been known before. Kaestner, a German physicist, speaks of an instrument invented by Becher, in 1656, by which an image of the Emperor Ferdinand III., painted on glass, presented itself at sunshine, but was hidden by clouds on gloomy days. It is stated that this apparatus moved automatically. Works of this kind can yet often he seen. The figures are moved by means of a cord attached to a body floating upon the mercury in a thermometer, the metal rising by expansion and falling by contraction. We read generally in books—so, for instance, in B. Silliman’s Natutural Philosophy—that the early thermometers indicated temperatures by the expansion of air; this, however, was not the case, for the air in the bulb was constantly filled with vapors of the water in the stem, which follows another law of expansion than dry air, thus making such an instrument necessarily very imperfect. Varignion calls them, more properly, manometers, as they indicated the densities of the inclosed air, and its changes in volume by an increase or decrease of temperature. Yet, there being no freed points on the scale, these instruments were not comparable between each other. The first standard point adopted was undoubtedly that of the freezing point of water. In his above-mentioned work, Dalencé writes the following on the graduation of the first thermometer: “The freezing point was indicated upon a small slip of paper. In summer, the bulb of the instrument was smeared over with some butter. When it melted, the point to which the water rose was again marked, and the space between divided into two equal parts. This mark was to indicate a temperature that was neither cold nor warm. Each of the two intervals was then subdivided into ten equal degrees, five of these degrees were marked upward from the point where butter melted, and five downward from the zero point; thins fifteen degrees for the cold and fifteen degrees for the heat were obtained.”

This was the first thermoscope with fixed points— a thermometer. Dalencé does not assign the invention to himself; and we are left in the dark as to who the inventor really was.