On Captain Parry’s and Lieutenant Foster’s experiments on the velocity of sound

• Published in: Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1833
• Subjects: Arctic; Beck; Parry; Laplace
• Online Access: http://dx.doi.org/10.1098/rspl.1815.0335; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1815.0335

In this paper the author institutes a comparison between the results of the experiments on the velocity of sound made by Captain Parry and Lieutenant Foster in the arctic regions, and those deduced from the theoretical formula of Laplace. At the temperature of —17°·72 of Fahrenheit, and with a barometric pressure of 29·936 inches, the mean result of all the observations gave a velocity of 1036°·19 feet per second. With the same data, this velocity, by calculation according to the formula of Laplace, would be 1017·72; differing from the observed velocity by 17·47 feet only. Similar comparisons of particular observations, which are selected as being made under favourable circumstances, with the deductions from theory, are made by the author with but little variation in the results. From the whole investigation, he draws the conclusion, that in very high latitudes, where the cold is very intense, the data on which the calculations are founded are more uncertain than at ordinary temperatures; thus confirming the opinion of Laplace, who says, in speaking of these differences, “qu’elles paraissent être dans les limites des petites erreurs dont cette experience, et les élémens du calcul, dont j’ai fait usage, sont encore susceptibles.” The author shows by an elaborate calculation, that the influence of moisture in the atmosphere on the velocity of sound must at these two temperatures be quite trifling, not amounting in any case to more than a few inches in a second; and that this element may therefore be safely neglected in the computation. He next proceeds to compare the experiments of the northern navigators with those of Dr. Van Beck and himself, and also those of other observers, adverting to their general agreement; which, he observes, is sufficiently satisfactory to warrant the conclusion, that whatever difference may still be found to exist between computation and observation, is rather to be ascribed to some imperfection in the theoretical formula, than to any fault or negligence in the observers. He concludes ...