S. B. Williams — Lavoisier and Laplace's Method. 181 



As will be noted, the essential difference between this 

 arrangement and that of Lavoisier and Laplace is that the 

 steam-jacket and rod are here arranged in a vertical position. 

 A small rubber band at o holds the tube, A, lightly against 

 the Y opening at Y. By means of corks in the ends of the 

 tube, particularly the lower one, the steam-jacket is supported 

 on the rod, R, which in turn rests on its end in a depression in 

 K. This insures that the lower end of the rod will always 



Fig. 2. 



cz 



remain in a fixed position without the necessity of clamping it, 

 and prevents the tube from creeping due to its own expansion, 

 In some five or six devices for measuring the linear coefficients 

 in which the steam-jacket rested in a horizontal position in Y's, 

 as in figure 3, I have found that the tube creeping carried the 

 bar along with it; this is usually overlooked by the student 

 and the results obtained are very discordant. 



K is a thin strip of brass with a small depression in which 

 the lower end of the rod rests. In one type of expansion 



