AND RATIO OF THEIR ATOMIC WKUillTS. 



35 



During the (leteniiinutioii of the pressure of the gas in the globe a, Fig. 11, 

 the cylinder containing it stood at- tlie eentre of tlie taid< _/'_/', so that a sufficient 

 thickness of ice could lie [)laced on every side of tlie globe. But foi'the subsequent 

 use of the apparatus this globe had to be neai' the side of the tank. The cylinder 

 h b was therefore held free from the tank while the latter was moved into its 

 new position, when the globe full of hydrogen was again su})[)oited by resting the 

 containing cylinder on the bottom of the tank. The differential manometer was not 

 disturbed. 



•2'2. OXYOEX I!Y SEOONP MWriloD. DKSICC.VrOIiS FOR IIOLDTWO GLOBES. 



The globes used for weighing oxygen in this series of determinations were 

 kept, during the whole course of an experiment, in desiccators, one of whicli is 

 shown in Fig. 13. A copper vessel 

 has a flange and cover at a, and a glass 

 plate secured to a flange at //. At the 

 centre of this plate is a fitting into 

 which may be screwed a socket carry- 

 ino- the glass tube c. The whole is 

 water-tight. 



The counterpoise <l simply rests 

 on a [)aii e, excejit when the cover is 

 removed and the counterpoise sus- 

 pended to the balance. The globe /, 

 however, must be firmly held in order 

 that the key of its stopcock may 

 be manipulated. It is accordingly 

 grasped by the clamp shown in Fig. 

 14. The Jaws a, a are moved in opposite directions by the right-hand and left- 

 hand screws on the shaft h. A key which turns this shaft can be removed and 



the opening stopped with a cork. When the globe is held 

 by this clamp, a handle f/, Fig. 1?., can be pushed forward 

 so as to turn the key of the stopcock. When this handle 

 is withdi'awn and the globe is suspended from the balance, 

 the jaws are made to release the globe which then hangs 

 r, f . n- perfectly free. The glass tube c. Fig. 13, is removed during 



Fig. 14. — Clamp for holding I J ° 



globe while in the desiccator. the Wci'^hin*'". 



When it is desired to exhaust a globe in its desiccator, it is secured by the 

 clamp, a ground joint is fitted in place, as in Fig. 6, and the desiccator is set near 



Fig. 13. — Desiccator for containing -ind manipulating globes 

 during filling, weighing, and exhaustion. 



