THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. XLII. — Some New Measurements with' the Gas Ther- 

 mometer ; by Arthur L. Day and J. K. Clement. 



First Paper. 



Many of the serious problems of rock formation are depend- 

 ent upon the exact measurement of temperatures, in the 

 region lying between 400° and 1600° C. It is, therefore, not 

 surprising that a considerable portion of the energy of inves- 

 tigators in this branch of geophysics (see in particular Barns, 

 Bulletins of the IT. S. Geological Survey, No. 54) has had to 

 be expended upon the methods and mechanism of high tem- 

 perature measurement. This situation not only still exists, 

 but the increasing perfection in other lines of geophysical 

 analysis has created a demand for considerably higher accuracy 

 in the temperature determinations, if snch shall prove attain- 

 able. This has been the chief incentive for the present long, 

 difficult and still incomplete investigation of the gas ther- 

 mometer. 



A discussion of gas thermometry in its more general aspects 

 is not contemplated in the present article. This has been done 

 from time to time by others,* and its underlying assumptions 

 found to be sound and adequate. There is, therefore, no need 

 to go over this ground again. On the other hand, there is no 

 denying the fact that a great deal still remains to be done upon 

 the experimental side before the steadily advancing require- 

 ments of both science and industry in the matter of a trust- 



* See in particular the several papers of Chappuis, published in the Tra- 

 vaux et Memoires du Bureau International des Poids et Mesures and the 

 Eapports presentes aux Congres International de Physique ; Carl Barus, 

 Les Progres de la Pyrometrie, Eapports presentes aux Congres International 

 de Physique, vol. i, page 148 ; E. Buckingham, Bulletins of the Bureau of 

 Standards, vol. iii, p. 237. 



Am. Jour. Sci. — Fourth Series, Vol. XXVI, No. 155. — November, 1908. 

 29 



