Treatise on Heat

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAP. III. THE DILATATION OF GASES. By the experiments of Lavoisier and Laplace, mentioned in the last chapter, it appears, that metals'dilate uniformly with the increase of temperature between the limits of 32 and 212 of the common thermometer. This uniformity of expansion is still more conspicuous, and extends through a much wider range of temperature in the case of bodies which exist in the gaseous or aeriform state. Indeed, there is a uniform character about the expansion of these, not only when each gas is considered separately, but when gases the most different in other qualities are compared together; which leads to the adoption of their expansibility as a standard of comparison for determining the expansibility of all other bodies. About the same period in the year 1801, Mr. Dalton, at Manchester, and M. Gay Lussac, at Paris, instituted a series of experiments on gaseous bodies, which led them to the conclusion, that the dilatation of air proceeds with perfect uniformity in reference to the mercurial thermometer, between the temperatures of melting ice and boiling water. But what was still more remarkable, they ascertained, that all gases whatever, and all vapours raised from liquids by heat, as well as all mixtures of gases and vapours, were subject to exactly the same quantity of expansion between these limits. Mr. Dalton found that 1000 solid inches of air, raised from the temperature of melting ice to that of bdiling water, increased their bulk to 1325 solid inches According to M. Gay Lussac they increased their bulk to 1375 solid inches. The latter determination hasbeen proved by subsequent experiments to be the more correct. It appears, therefore, that for an increase of temperature from 32 to 212 amounting to 180, the increase of volume is 375 part...