Carl Barus Quotes (1856-1935)

“Of the Planck molecular oscillators... If operating continuously under the established electromagnetic laws they lead to the impossible distributions of energy in the spectrum investigated by Rayleigh and Jeans. But if emitting only, when their energy content is a whole number of energy elements, a case thus involving the entropy probability of Boltzmann, Wien's law and the numerical data referred to are deducible with astounding precision.”

“The presiding officer of this [Physics] section was Prof. Carl Barus, who fills the chair of Physics in Brown University. His inaugural address was on "Long Range Temperature and Pressure Variables in Physics." He began by giving a history of the various attempts to provide suitable apparatus for high-temperature measurement. Fusion first played an important part in the manufacture of thermoscopes, and later those instruments based on specific heat showed an advantage over the fusion instruments. The gas thermometer was referred to as the only fruitful method of absolute pyrometry. The speaker dwelt at length on high-temperature work, the first thorough-going instance of which was by Prinsep in 1829. Then the experiments down to 1887 were considered in detail, and the conclusion reached that the data furnished by the Reichsanstalt will eventually be standard. ...Turning to the applications of pyrometry, he referred to the variation of metallic ebullition with pressure. Results already attained show an effect of pressure regularly more marked as the normal boiling point is higher. Igneous fusion was considered in its relation to pressure and with regard to the solidity of the earth, and the inference was drawn that the interior solidity of the earth, now generally admitted, is due only to superincumbent pressure, withholding fusion. The question of heat conduction was next taken up, and the results deduced by various writers as to the age of the earth discussed. High pressure measurement was lengthily dealt with. Passing from this subject, the entropy of liquids was considered. ...The paper ended with a reference to isothermals and several kindred subjects.”

“In the decade between 1882 and 1892 contributions to gas thermometry and the measurement of high temperatures are few and unimportant, but work was begun in those years on both sides of the Atlantic which, for the experimental skill and persistence with which the experimental difficulties and limitations were pursued and successively overcome, surpasses any effort which has been made either before or since that time. These were the investigations of Barus at the U.S. Geological Survey in Washington and of [Ludwig] Holborn and his colleagues at the Reichsanstalt in Charlottenburg. Barus (1889) recognized as no observer who preceded him had done, the superlative importance of a uniform temperature distribution about the gas thermometer bulb for purposes of high-temperature measurement, and he took the most extraordinary precautions to maintain it. A temperature of 1000° C or more is not attained without very steep temperature gradients in the region immediately surrounding the zone of highest temperature. It is therefore a problem of great difficulty to introduce a bulb of from 10 to 20 cm. in its largest dimension into this hot zone without leaving some portion of it projecting out into a region 200° or 300° lower in temperature. Burning mixtures of gas and air for heating purposes also contributed to the irregularity and uncertainity of the temperature distribution about the bulb. Barus sought to avoid this by a method of great ingenuity, but also of great technical difficulty. He inclosed his bulb within a rapidly revolving muffle which by its motion protected every portion of the bulb from direct exposure to a particularly hot or a particularly cold portion of the adjacent furnace. This complicated furnace structure and consequently inaccessible position of the bulb made it impossible to introduce into the region about the bulb the substances whose temperature constants were to be measured and compelled him to use thermo-elements which were first calibrated by exposure in the furnace with the bulb and then used independently to measure other desired temperatures. The thermo-element has continued in general use in this intermediary rôle since that time. In the preparation and use of thermo-elements Barus also made much more extensive and elaborate studies than any one who has followed him. ...It is an unfortunate accident that history has failed to record Barus's name along with that of Le Chatelier in the development of the thermo-element for purposes of high-temperature measurement. It hardly admits of question that Barus contributed incomparably more to our knowledge of the thermo-electric properties of the different metals and their use than his distinguished French contemporary, but the 10 per cent iridium alloy which he finally selected proved to be less serviceable than the 10 per cent rhodium alloy developed by Le Chatelier... And so we find the Le Chatelier platin-rhodium thermo-element in use to-day the world over, while the magnificent pioneer work of Barus remains but little known.”

“[T]he author, whose work on nuclei is well known, describes a number of investigations carried out with his fog-chamber apparatus. The apparatus having been sufficiently improved, it was used for various experiments, including the growth of persistent nuclei, the production of water nuclei by evaporation, the results obtained when X-rays are allowed to strike the fog-chamber from different distances, the effect due to radium, &c. Other problems dealt with in the book are the distribution of colloidal nuclei and of ions in media other than air-water, the simultaneous variation of the nucleation and the ionization of the atmosphere of Providence, and the variations of the colloidal nucleation of dust-free air in course of time.”

“When the history of the progress of physics in the United States during the late nineteenth and early twentieth century is written, the name of Carl Barus will occupy an important place.”

“Carl Barus loved music, and composed about fifty compositions, among them a March to Pembrok Hall... and an Ode to the Steam Shovel, inspired by the daily noise outside his laboratory and was presented by him to President Faunce.”